MadModder
Gallery, Projects and General => Project Logs => Topic started by: Darren on April 17, 2009, 07:20:25 PM
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Inspired by Mickn in his post in the introductions section, and by Ralph flashing off his garage door motors I purchased a car windscreen motor.
This one came from Ebay priced at £5.00, it's Saab 900 GM 9-3 Front Windscreen Wiper Motor
Here you can see I've opened it up to have a look inside. I'm using one of my bench power supplies to test it.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1710.jpg)
After fully stripping it down to look it over it was obvious that it was well built. All the wiring was a hefty gauge as you would expect with low voltage devices. (low voltage = high current for a given power, so wires need to be beefy) The insulation also looked to be in good order.
I tried voltages from 0-30V DC, the 12v motor is quite happy from 1.5V to 30V, I left it running for about 20 min continuous at 30V and no problems were detected. This is well over what it would be expected to do on a mill. At 1.5V it did seem to still have plenty of power, I certainly couldn't stop it by hand but the real test will have to be on the mill.
BTW, it's real slow at 1,5V and 30V would give a nice quick tram to shift the table over.
I'm lucky, I have all the power control I would need it the unit you see above. That's a 0-30V at 20A supply. I can barely carry it, I'm not sure that I can any more ::)
Oh the motor runs at 4A at 12V, I'll test the current draw at other voltages tomorrow as we need to know this if building a power supply (PS) from scratch.
Mick, how did you sort the variable speed? Did you use a pot as a shunt? If so what value?
The motor has three wires, this I assumed meant three brushes. I had a look inside and sure enough there they were. Two opposite each other, the main two, and one offset. I assume this was some sort of second speed control. But for the life of me I couldn't get it to do anything no matter how I connected it. I'll try again tomorrow as I've just had another idea. It could be useful.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1709.jpg)
Also on this unit fitted to the large plastic wheel is a copper plate, this is some sort of counter trigger, maybe speed or maybe just a counter. There are sprung contacts on the cover plate that connect to this disc. Maybe someone can think of a use?
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A little Googling and it seems the copper "counter" plate is for an auto park mechanism. Ie stops the motor is the correct position.
But we could poss do something else with it.
The three wires are for two speeds, One is earth and two are lives. one for fast and one for slow. But I could only get one to work. I'll try again tomorrow.
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Right then, I have now got both speeds working, you don't want 30V, ignore what I said before as that was on the slow speed.
Fast speed is much faster and 12V is prob too much. At around 6V you can switch between the two speeds and this seems to be a good compromise if you don't want to make a variable voltage circuit. maybe a 6V bike charger will do?
I need to get my rpm tester out tomorrow and see what it is really turning at.
later... :thumbup:
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Darren, I suggest looking for the circuit diagram of the donor vehicle. That would give an indication of how the three wires were used and hopefully would give the value of any resistors etc, I assume they are related to speed control.
If you are going to use a pot as the speed control it would need to be a high wattage, low resistance kind, I would suggest pulsing the motor for speed control. But if a simple pot control is required use it with a pass transistor, 2N3055 maybe?
One possibility would be a low voltage lighting or old electric blanket transformer (not a switch mode power supply kind). They will give you AC but that motor (if it has a magnet in it) will require DC, easily provied by just one diode which will give half wave rectification. In electrical terms that would be a very 'rough' output but ideal for motor use. Then use a light dimmer to supply the transformer.
Wiper motors are great in that they can be set to do one revolution then stop, that opens up interesting possibilities.
But really, there are more ways of doing this than skinning a cat.
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Hi John,
I've got a circuit I made up some time ago using a 2n3055 controlled by a Lm317 I think, but it may be some other chip.
I'm thinking that whilst I can do this there must be something simpler for the other chaps. What about just putting a pot in series with the motor. We are not looking for finesse power supplies here and whilst the pot may be wasteful energy wise we are using the mains and not a battery. So less important in this scenario.
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BTW, I've got transformers coming out of my ears here, along with variacs, transistors etc etc.
I can make nice power supplies from low voltage to 4.3KV at 5amps. Used for some big valves !!
But forget all that, sometimes it's hard to make something simple. Bit like what Bogs said about once you start doing something precise it's difficult to just knock something up.
What you think about the series pot, I've never tried it, I'll see if I have something suitable tomorrow.
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Or like you said,
Use a dimmer switch to a 12V transformer followed by a rectifier, (never tried a single diode, but half wave should be fine) That should do it?
Dimmer switches are easy to find, as are 12V transformers.
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Re the pot, 12V at 4A is 48 watts so to run your motor on that supply would need a 48 watt pot! That would look like one of those old resistance coil things they once used to control stage lighting!
Do you have any nicrome wire? Perhaps the heater from an old clothes dryer? As an experiment just stretch a single wire, a foot or so, between two nails in a bit of wood and use a couple of battery clips to put more or less in series with the motor, that will give you a feel for what a pot control would be like.
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Half wave means higher voltage for the same amount of power, more easily overcomes inertia etc at low speeds (I think).
Not all dimmers are the same but I think that would be worth a try.
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Yes, quite right, low voltage = high current, hence using a dimmer on the 240V side. Far far lower current there.
BTW, I wasn't thinking of using a pot on it's own but in series with a resistor to take the load.
I do have nichrome wire, in the form of some very large ceramic tubes as variable resistors, but these are not very practical :lol:
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Yea, but a pot in series with a resistor is just a pot with less than full travel! Whenever you use a resistor, pot, or something like a transistor in voltage follower mode you have to dissapate a lot of heat so the components have to be big.
I think the easiest for those who dont want to mess with electronics would be the lamp dimmer, low voltage tranny and the rectification diode. Providing of course that it works! I have not tried it! ::)
What is the requirement for a mill feed anyway? A steady slow, controllable, speed?
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But we don't need the full pot control as we are looking for about a 3-5V variation and the amperage then drop considerably
Duh, sorry John, my mistake, just realised, using a series resistor the voltage will certainly drop but the current won't alter :bang: :bang:
I do have some CB radio power supplies that use a 2n3055 output. I'm just thinking remove the voltage setting resistor and replace it with a pot.
That might be a very cheap and easy option. These power supplies can be picked up for a fiver or so. A pot is pennies.
This way you even have a tidy case to put it all in.
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Then use a DPDT switch for forward/reverse, a couple of micro switches to limit bed travel, these could even be adjustable with the mill bed stops.
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Hi Darren,
You guys certainly know more about electronics than I do.My speed control was via a small dc control unit from Maplins
Panel Mounted Speed Regulator Module
Order Code: RN41U
This I use on the horizontal table feed. Its fed by one the yellow 12volt supply leads from my old PSU to the windscreenwiper motor. Another 12volt lead supplies the vertical slide. This is purely up and down and saves winding and does not need regulating its on the fast terminals in the other windscreen wiper motor.Sorry I cant be more technical
Mick
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Thanks Mick, that clarifies things a bit...
The Maplin module can be found here http://www.maplin.co.uk/Module.aspx?ModuleNo=30310&TabID=1&C=SO&U=strat15&doy=search
It's £15.00 + P&P and it's rated at 3amps with a 5A peak. Whilst it would work fine at lower speeds (the current draw drops significantly) it might be on the edge at 12V and deff higher. Just bear this in mind if you decide to use this and keep those speeds down a touch.
ATX power supplies look good at 30A for a 500W unit, more than enough to power 3 motors at the same time !!! Not that you would want to... :ddb:
With 3, 5 and 12V outputs the choice is mind boggling. I'm assuming you can series connect them?? I'd have to try this to be sure.
But this could give you 3,5,8,12,15,17, 20V speeds on a rotary switch without using a variable power control.
If the unit will let you reverse connect (it might not) there is potential for 2, 3, 5, 7, 8, 9, 12, 15, 17, & 20V Three extra speeds. That would cover all speeds you would ever need. Don't forget the motor also has two speeds as well.
All without any complicated circuitry.
Not sure if I have an ATX power supply unit spare.
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Can I ask if anyone is finding this interesting as i seem to be rambling on a bit here....as usual... :ddb:
If you want me to carry on I'll knock something up and do a "how to" post to clean the thread up a bit.. :thumbup:
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please carry on , I am waiting to see the end result
dave
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OK, I found a CB transformer power supply and an ATX supply.
I decided to start with the CB unit as this is about the simplest "proper" way to do this that I can think of for those that are not proficient with electronics. This is mainly because most of it is already done and you only have to make a small change to the circuit.
By proper I'm referring to a regulated supply, that is one that will not fluctuate in voltage even if the mains does. It will also keep the electricity supply company happy by not introducing noise into the mains supply.
The power unit
Oops, I seem to have lost a picture, you know what they look like I'm sure. If not have a look on Ebay. You will need one that is rated for 5A or more. That way we know the circuit will be the right sort.
Here it is opened up, nothing much inside. Just a small transformer and a circuit board.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1712.jpg)
The bit you need to look for is the voltage setting device. This will be a resistor or a zenier diode (auburn coloured glass)
You can see it here pointing vertically.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1713.jpg)
Closer view
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1714.jpg)
We need to disconnect this and take it out. Replace with a variable resistor of about 5 - 10K value. I used a 10K as it is what I had to hand.
You can see two wires soldered to the board, these are connected to the variable resistor (pot). Doesn't matter which way round the wires go. On the pot connect these two wires to the middle and one outer connection. Again doesn't matter which outer connection you use. One connector on the pot will have nothing connected to it. we don't need to use this.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1715.jpg)
The clip leads are connected to the original power output of the unit and connected to the motor.
That's it...all we need now is a reversing switch, I'll do this later and fit it back into the case.
Here is a video, not very clear, sorry, but you will get the idea. Notice when I unclip one cable and the motor speeds up, we could add a push switch here for quick transverse of the mill bed. Hold your finger on to power, let go to revert back to the pot setting speed.
The digital meter is showing the Amperage, not voltage. I found that on the motor the high speed used much lest current (amperage) than the slow speed. I really don't think we need to be bothered with the slow speed.
Hope you enjoy the video, it's rough...... :ddb:
I will fit it all in the case later....
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/th_MOV00063.jpg) (http://s401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/?action=view¤t=MOV00063.flv)
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Now time to put it all back in the case,
This is the reverse switch, it's a DPDT center off. ( Double Pole, Double Throw, Center OFF ) Meaning it switches both positive and negative with three lever positions. on-off-on.
Note the black and yellow wires and how they are connected. The center is the feed from the power supply and the two outer positions both go to the output terminals/motor. Only one side works at a time.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1717.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1723.jpg)
Drilling the hole for the direction switch, another was drilled for the speed control pot.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1719.jpg)
From above, the whole internals where moved back and extended wires made up for the LED on/off light.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1724.jpg)
And finally here it is with it's lid on.
The only thing I would like to add is a momentary switch for the rapid tram control. That way the desired speed setting can be left alone.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1725.jpg)
Hopefully this vid will demonstrate it working....
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/th_MOV00064.jpg) (http://s401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/?action=view¤t=MOV00064.flv)
There, a simple but very versatile power supply from very inexpensive parts, or the junk pile in my case...... :)
Now then, fitting the motor to the mill.....or lathe or rumbler.....now there's a thought......!!!
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Great job and a very informative write up :thumbup:
Cant wait to see it working on your mill.
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Good work Darren :thumbup: :thumbup:
Like I said, more ways than skinning the old moggie! :bow:
However, are you happy with the resistance replacing the zenor? The zenor is a constant voltage reference, how about this variation?
(http://farm4.static.flickr.com/3303/3453094491_8fafb13230.jpg?v=0)
The red lines are the new bits. This will retain the voltage regulation whereas just putting the pot in place of the zenor converted your voltage regulated circuit into a variable resistance circuit where the pass transistor amplified the function of the pot.
[Thats all assuming of course I understand what I am talking about!]
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I don't think that would work John, you are keeping the 12V zener and paralleling a resistance to it. This would only serve to lower the output voltage as it's the reference to the transistor. You might not be able to get 12V output.
The zener is only a reference device, most of these circuits use a resistor instead. But the zener is more stable than a resistor and you can get them in many voltages. 12V zeners just happen to be handy to the manufactures of the circuits as they are always accurate. Resistors rarely are.
I think if you look at the semiconductors PDF files they will show a resistor and not a zener. The pot is just a variable resistor as you know. Therefore it varies the reference voltage to the transistor.
At the end of the day it's only a simple amplifier circuit.
I use this sort of set-up on my audio valves heaters where quality is paramount. The last thing we need here is noise getting into the circuit to be amplified along with the audio signal.
For this sort of use for powering machinery it's pure overkill. But it also happens to be convenient :thumbup:
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John, I should have said, on this circuit the zener was not regulating the output transistor but instead the smaller transistor before it.
I've no idea which one it is, didn't look, and the output transistor is a BD142, similar to the 2n3055 but rated at 15A not 35. More than good enough in this application.
I've been playing with the ATX power supply this evening. Interesting, never really considered them before.
You can't add or subtract the voltages as the protection circuit kicks in and switches the whole unit down,
So really stuck with 3,5, and 12V outputs all with good heavy current capabilities. The 3V can only be used with the slow speed circuit on the wiper motor. For some reason it won't work with the high speed. I don't know why there should be more than enough current as it's stated as 14A.
And on my unit the 12V is only 10V. I don't know if this is typical?
It works, and is probably good enough for powering the mill bed.
If anyone wants me to demonstrate please shout up. You lot are so quiet on this thread I'm wondering if the world has come to an end whilst I've been locked in the cellar :lol:
I do hope someone has benefited, cos I didn't really need one, but it will be used now its been made :ddb:
If anyone is still confused speak up.... :thumbup:
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Darren,
Don't be worried, we all have our own specialities, mine ISN'T wiggly amps and electric string, and also, I've got my feeds sorted already.
You just might be way above most of us, and we are just sitting back waiting for the punchline.
Bogs
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Darren, if the 'top' to the zenor goes to the base of a small transistor you may find the collector of that transistor is connected to the base of the big transistor, this is a Darlington pair configuration and the small transistor is amplifying the base current for the big transistor and allows the use of a smaller wattage zenor.
The zenor conducts while the top end is equal or above its zenor point the end result being that the top of the zenor is kept at a constant voltage. Connecting the pot as I showed is a voltage divider across the zenor, so, wind the pot contact to the top and the full zenor regulated voltage is applied to the following circuit, in this case the base of the smaller transistor in the Darlington pair, the pot in that position is the same as the original circuit disregarding whatever current there is through the pot (which should not be much). Wind the pot down a little and you are tapping off a voltage less than the zenor voltage which means less voltage on the base of the Darlington pair. If you want a voltage higher than the original then change the zenor for a higher voltage one, or you can add a diode to the zenor (in series) or a string of diodes each one increasing the voltage by about .6V.
My own bench power supply (which I made back in the '70's) has 32 diodes carefully soldered in series around a 32 position switch which provides a voltage from about 1.2V to 20V which is applied to the bases of four parelleled 2N3055s, in those days the switch was much easier to find than an integrated regulator! Though technically very crude such a circuit is simple in concept and is relatively 'smoke tight'.
The ATX power supply wont let you series the different voltages because they all share a common earth, the best you could do would be to take one of the positive voltage and 'add' it to one of the negative voltages but in most cases the negative voltages will not handle much current so it is not worth much for our purposes. If you are really keen there are dozens on pages on the web showing how to modify and make use of these power supplies. But to drive an electric motor I doubt it is worth the bother.
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Darren, if the 'top' to the zenor goes to the base of a small transistor you may find the collector of that transistor is connected to the base of the big transistor, this is a Darlington pair configuration and the small transistor is amplifying the base current for the big transistor and allows the use of a smaller wattage zenor.
I'd have to draw the circuit out, but the emitter of the 1st transistor should go to the base of the 2nd transistor as shown in this diagram for a Darlington pair.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/darling.gif)
The two collectors should be common? That's how they increase the current capabilities in the order of 10,000.
Unless I'm missing something?
This is the schematic you are proposing....I think? Would that be correct?
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/PowerSupplycopy.jpg)
And this is what I have done, replaced the zenner with a variable resistor.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/PowerSupply2copy.jpg)
Sorry but I still can't see how the zener helps? You have it in series with the pot with both ends tied to ground. At one end the voltage/current will flow through the zener (high speed) and at the other it will flow through the pot (low speed).
But the high speed will be limited to 12V by the zener, whereas they way I have it I can go to the full 20V of the transformer.
Unless I'm misunderstanding the schematic you are proposing, entirely possible...!
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Darren, your schematics are exactly as I was thinking. One advantage of leaving the zener in the circuit is that you wind up with a regulated output.
More significantly however consider what happens in your circuit if you set the pot to near the top of its travel, set up there you have the full supply voltage over a small segment of the pot, high voltage over low resistance means hight current and quite possibly a little puff of smoke escaping from the pot as it suddenly burns out!
Of course you dont have to keep the zener but I suggest you have the pot in the configuration as per my schematic that way you wont be stressing the pot.
I think the pot should be a few Kohms and be aware that pots come in different 'tapers', linear and log(aka audio), I think a linear would be best for this job but might be harder to find.
Sorry for my mistake regarding the configuration of a Darlington, your diagram is correct and shows how the gain of the first transistor multiplies the gain of the second.
[Well, those are my thoughts anyway! :coffee:]
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how about this variation?
(http://farm4.static.flickr.com/3303/3453094491_8fafb13230.jpg?v=0)
Zenner is upside down
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how about this variation?
(http://farm4.static.flickr.com/3303/3453094491_8fafb13230.jpg?v=0)
Zenner is upside down
Antipodean Zener?
[Indeed that Zener is shown upside down assuming it is a positive supply circuit.]
:bow: :bow:
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"Antipodian Zenner?:beer: :beer: :beer:
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Who wants to see a video of my mill with power feed operating the table.... :ddb: :ddb: :ddb:
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Oh Oh Oh Oh, I do I do. :ddb: :ddb:
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OK John, I see where you are coming from now,
Re the connection of the pot, yes I accept what you are saying, although I have several similar power supplies used for my Hifi to power large valve filaments.
In twenty years I have yet to see one let the magic out (smoke) The theory is sound though.
We have no need for a regulated supply here, after all we are only powering a motor, nothing critical. So the zenner is really overkill in this application whilst at the same time it becomes a limiting component. I'm more concerned with back EMF when switching the motor off. Normally one would use a reverse diode, but difficult here because we have a reverse polarity switch. I need to think some more on this. However, it may not really be a problem. More "correct" theory.
Simple is always best :thumbup:
If I were to really want a proper regulated supply I would probably use a 317 as a variable voltage device to reference a 2n3055. Or as I have done in the past a pair of 2n's if the current demand warrants it. Sometimes it does. Valves with heaters at 10V/10A can be pretty demanding to build a supply for, esp when you have four of them to supply.
Remember, we don't want to feed them AC and this is where the problem starts.
However,
This thread was not intended to be an in depth electronic topic. It was about making a simple variable power supply for those with no real electronic experience.
I believe I have shown what can amount to not only the simplest method to achieve this, but the cheapest as well. These are important factors as this is not an electronics forum. Guys here mostly chop metal, not solder.
This thread was deliberately never intended to become technical, that really scares peeps from trying altogether. Quite honestly we have discussed things that didn't belong in this topic.
If anyone other than John and I are still reading this, what I have proposed is really quite simple and cheap. Ignore all the other stuff, none of it applies to what we need here.
I have now powered the mill with this power supply and motor. I was going to show you but my phone battery went flat. I'll take a video tomorrow.
BTW, nothing too exciting as I'm holding the motor by hand, but I have made a nice linkage in delrin.... :thumbup:
You should be able to make this supply for about a fiver, tenner at the most if you are unlucky.
If anyone decides to go down this path, there is always help available. Even if I have to do it for you !! :dremel:
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Darren :beer:
Just to summarise my position, a tranny, rectifier, pot, transistor is about as simple as you could get, if you need more current add a big transistor in a Darlington configuration, if you need lots more current add a bunch as 'pass transistors' (I have four 2N3055s in my old power supply). If thats all too daunting the aforementioned lamp dimmer before the tranny and rectifier must be the easiest of all.
Good work, lets see that video!!! :ddb:
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Hi :wave:
I seem to be a few days late to this party :(
I couldn't have helped with the electrictrickery but I sure would have had the pom poms out cheering you on darren :ddb: ...... Ok, that's just wrong! (Pom poms.... I would never.... Honest! :lol:)
I've got some reading to do to catch up with all this .... I'll have some stuff to figure out too as all my stuff is rated 24V!
Very good post Darren, and all other technical contributers :thumbup:
Bring on the vid'!!! :D
Ralph.
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Way to go Darren :thumbup: :thumbup:
I'm having problem following what you're doing, but thats my fault not having any background at all in electronics.
Can't wait to see your mill working under power
Stew
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Some photo's for now.... :wave:
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1727.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1729.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1728.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1730.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1734.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1735.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1736.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1738.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1740.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1741.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1742.jpg)
I'll take the video later and post.... :thumbup:
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Sorry to take so long to get this up...life got in the way today..... :ddb:
Bear in mind it has no frame yet to hold it in place, and I was balancing the camera with one hand, holding the motor with the other whilst wondering where my third hand was to control the speed and switches....fun, fun, fun...
But hey, it works and more will come of it :ddb: :ddb: :ddb:
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/th_MOV00066.jpg) (http://s401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/?action=view¤t=MOV00066.flv)
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Nice job :thumbup:
I would have never thought of coming out of the rear of the gearbox :bow:
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That looks good so far! :thumbup:
Will you be able to turn the feed by hand with the motor attached when setting up etc?
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Thanks Jason,
I'm afraid I can't take the credit for that idea, as much as I'd like to.... :clap:
Nope, the credit goes to Marc "The Tinkerer" From Australia http://home.swiftdsl.com.au/~thetinkerer/projects/projects.html :thumbup:
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That looks good so far! :thumbup:
Will you be able to turn the feed by hand with the motor attached when setting up etc?
Thanks John, yes no problem there, I can think of three ways to achieve this quite easily. I'll have to decide which one I'm going to go with...
Ralph, one hand wheel can be got around, 24V motor would still work with this supply. In fact it might work better than the one I have.
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Prototype proven Darren, super job.
On the home run now. :ddb: :ddb: :ddb:
John
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Well done that Man :clap: :clap: :clap:
Stew
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I'm having problem following what you're doing, but thats my fault not having any background at all in electronics.
Can't wait to see your mill working under power
Stew
Stew/Ralph
If you want to take the easy way out have a look at this, if you want it then snap it up I have not seen many on Ebay.
It's suitable for 12/24V.
You will only need a 12V or 18V transformer to go with it, they are easy to find, Ralph has some....I might be able to sort one out as well. I'd have to go hunting....
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=260392906819
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This would do as well
http://cgi.ebay.co.uk/12V-15A-PWM-DC-Motor-Speed-Control-Regulate-RC-Model_W0QQitemZ350182394836QQcmdZViewItemQQptZUK_Cars_Parts_Vehicles_Terminals_Cabling_ET?hash=item350182394836&_trksid=p3286.c0.m14&_trkparms=72%3A1683|66%3A2|65%3A12|39%3A1|240%3A1318
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Darren
Thanks for the ebay links I've put a watch on the first one we've got to be carful, don't want to be bidding against Ralph :doh:
I may go for the Euro one from Irland its got a buy it now, about 20 squid with postage.
Stew
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Which one is that Stew, I can't see one from Ireland?
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:doh: I got that wrong its Shangie
Unless ther's a Shangie in County Clare :lol:
Stew
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Oh I see, it's in China :thumbup:
You will need a transformer as I said before and a rectifier to go with it.
Rectifier turns AC voltage from the transformer to DC which the module needs.
Now that is going to set you back :lol: :lol: :lol:
http://cgi.ebay.co.uk/8A-Bridge-rectifier-100v-x-1-ROHS_W0QQitemZ270314229523QQcmdZViewItemQQptZUK_BOI_Electrical_Components_Supplies_ET?hash=item270314229523&_trksid=p3286.c0.m14&_trkparms=66%3A2|65%3A15|39%3A1|240%3A1318
Don't buy any old rectifier, let me see what you are looking at before you buy... :thumbup:
You want probably 6A minimum, bigger is better but no need to go silly. The one I linked is fine and easy to mount.
I'll show you how to connect it later. Easy I promise... :thumbup:
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That Shangie site also sells these would they be any good
http://cgi.ebay.co.uk/2X-12V-200RPM-Gear-Box-Motors-for-Cars-Boats-Robots-New_W0QQitemZ180346950349QQcmdZViewItemQQptZUK_BOI_Industrial_Automation_Control_ET?hash=item180346950349&_trksid=p4634.c0.m14.l1262
Stew
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I really don't know the answer to that, motors are not my thing really. But they look to be very small to me? Far smaller than a windscreen motor. Tiny in comparison.
I'll have to check what rpm mine is running at, 200 sounds a bit high to start with?
I paid a fiver for my windscreen motor.
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Darren, You're right, one handed opperation will have to be gotten around!
I was thinking possible belt drive? But that's all to be decided.... Need some time in my shop first!! ::)
Stew.... Why would you want to buy those motors when I have a whole load here? With transformers and all sorts of circuitry! I'm sure they would run just fine at 12V too? 2-3 of these motors were never even fitted!!! They were out of boxes with parts missing!
It's up to you, I will get over there soon and bring a selection of bits with me.... I've still got 5 sets (motor and transformer) in my shop going for free.....
If it helps I could charge for them!!?? I remember the one about the free couch, 2 days, sign on it "free, just take it" and no takers, put £40 sign on it, stolen in 20 min's!!! :lol:
The one I linked is fine and easy to mount
Really!!
I'm going to have to scour the circuit boards for a rectifier too.... Knew there would be all sorts of fun bits I'd have to find for this idea!
I'm very impressed with the way yours works in the vid' Darren, It has inspired me to get it done and useable on my machine :thumbup:
Now.... To E-blag wars!!!! :lol:
Ralph.
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Darren,
Nice speed control of the motor there. Be interesting to see how you finish it off.
Bernd
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I'm glad SOMEONE is having better luck with adding power feed. My mill flat out refuses to allow it to happen. My garage is a graveyard of useless motors, fried power supplies (added a new one to the pile today), and other assorted crap attesting to my many failures. I finally tossed the whole lot of other parts I had into the trash and am just going to keep cranking the #@$%^& handle. :bang: :bang: :bang:
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Did I ever tell you about the THREE power feeds on my mill. It came with the X axis one in the package, and because I was a good boy and paid up front before taking delivery, they threw in the Y & Z axis feeds, fitted by them, as FREEBIES (plus a load more stuff and a rather large discount as well).
I did have to buy the power supply for the extra two though, that was a 40 squid 110volt site transformer. But I thought it was a rather good deal at the time.
:lol: :lol: :lol: :lol:
(http://i202.photobucket.com/albums/aa102/bogstandard_photos/workshop66.jpg)
:ddb: :ddb: :ddb: :ddb:
I don't normally do it, but that is tool gloat.
I just couldn't help myself, as I knew you lot needed cheering up a bit.
Bogs
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Hmmmmmmmmmm..... something really odd happening here...... :scratch:
Bogs, is that not at least the third picture of that particular corner of your shop you have shown us, the corner beside the door where the fire extinguisher and the alarm panel are mounted? :scratch:
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Ah yes but, this is the first time I think you have seen the mill all by itself, showing it's THREE power feeds in all their glory. I can show you close ups if you are interested.
Oh, I forgot to add, even though not shown with the full layout on this shot, it now has FOUR axis DRO. X, Y and Z x 2. Plus of course, as we all should have, true variable speed from 0 to 2000 RPM, with FULL torque from the slowest to highest.
I'm now going very light headed, I am starting to feel like a true machine polisher. :lol: :lol: :lol:
Bogs
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Yeah but, but, but....mine cost me a fiver......
Oh OK, I'd rather have yours..... :lol: :lol: :lol:
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I'm glad SOMEONE is having better luck with adding power feed. My mill flat out refuses to allow it to happen. My garage is a graveyard of useless motors, fried power supplies (added a new one to the pile today), and other assorted crap attesting to my many failures. I finally tossed the whole lot of other parts I had into the trash and am just going to keep cranking the #@$%^& handle. :bang: :bang: :bang:
What have you been using for the power supply and motors?
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You know John, looking at that picture of your mill, I can't help thinking that it looks like it's gonna wake up and walk off.
Well, you did give it all that power, serves you right :lol: :lol: :lol:
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I was going to make a comment, but am afraid Bogs would "drive" that mill up were the sun never shines. :lol:
With all that power it would easy to do for him. :lol:
Bernd
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It was just a bit of light hearted relief lads, everything was getting just too damned serious.
You see, everyone's got LOL's in their posts now. :lol: :lol: :lol:
Bogs
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I'm glad SOMEONE is having better luck with adding power feed. My mill flat out refuses to allow it to happen. My garage is a graveyard of useless motors, fried power supplies (added a new one to the pile today), and other assorted crap attesting to my many failures. I finally tossed the whole lot of other parts I had into the trash and am just going to keep cranking the #@$%^& handle. :bang: :bang: :bang:
What have you been using for the power supply and motors?
I have a lovely 170 volt DC gearmotor that I cannot find a proper controller for. That thing has enough torque to twist your arm off...makes a nice paperweight. The motor I have been pinning my hopes on lately is from a 14.4 volt cordless drill. It is everything I need, plenty of torque, 0-600 RPM reversable, adjustable clutch, and small to boot. I can run it full bore using a 12v 6 amp battery charger and it does a fabulous job getting the table back and forth. The speed control is (was) built into the trigger, and it didn't have fine enough control. I broke down today and ordered this:
http://www.electronickits.com/kit/complete/motor/k166.htm
It eliminates the need for adding on a separate reversing switch, it uses a bi-directional pot for speed and direction control. One knob does it all. :thumbup: I will add a 12 volt muffin fan to the enclosure to keep everything cool and use the battery charger for a dedicated power supply. It is wired for long duty use, fused, and has 3amp amd 6 amp ranges in both 6 and 12 volt. I should have plenty of speed range with it.
I can't give up on it now...that would not be very madmodder of me would it?
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Stew.... Why would you want to buy those motors when I have a whole load here? With transformers and all sorts of circuitry! I'm sure they would run just fine at 12V too? 2-3 of these motors were never even fitted!!! They were out of boxes with parts missing!
It's up to you, I will get over there soon and bring a selection of bits with me.... I've still got 5 sets (motor and transformer) in my shop going for free.....
Hi Ralph I just posted those motors up for the Chaps who for distance reasons can't take up you're kind offer.
Thanks again :thumbup:
Hi Darren, Beleive it or not but I'm begining to understand whats required to do this job :zap: keep up the good posts. :thumbup:
Stew
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That's good to know Stew,
You don't need to understand it now, but picking up a few bits will certainly help later when you have it all in front of you :thumbup:
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Bit more on this tonight..... :ddb:
Thinking about Ralphs predicament in only having one handle I decided to do some re-thinking. Besides I belive the whole set-up will be more stable with the changes I have made tonight.
I ditched the delrin coupler and turned a new one from alloy.
I wanted a good fit so I used my bore gauges for a change to size the bore as I was going along. In fact it turned out so exact than when I tried the freshly machined and still warm coupler on the shaft, the cold shaft cooled it and I had quite a job to get it off again !!!
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1743.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1750.jpg)
This will be fixed to the mill shaft with an 8mm grub screw
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1762.jpg)
Next I decided that I needed a mounting plate for the motor, I decided to use a piece of MDF for the mockup and see how it goes. This could then be the template for the real thing later.
Note the pointy spotters for marking the hole locations on the MDF
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1753.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1752.jpg)
I didn't take any pic's of making the board, but you'll see it later.
Now I needed a way to mount the motor board to the mill. So off with the leadscrew bearing block, marked it up for drilling and tapping to 10mm.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1754.jpg)
Sometimes things just ain't big enough, so you have to improvise :dremel:
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1756.jpg)
A pair of tubes
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1785.jpg)
Ends threaded to 10mm
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1759.jpg)
Studs fitted to the leadscrew bearing block
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1758.jpg)
And two tubes fitted.
Two inserts made with 6mm threaded ends
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1760.jpg)
These slide inside the tubes and are a snug fit
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1761.jpg)
Motor board fitted onto the sliders
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1786.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1787.jpg)
Slide the motor onto the gear wheel to engage
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1790.jpg)
Slide back to dis-engage
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1791.jpg)
Simple pimple :)
And this nut stops it falling off, motor board slides to the nut when dis-engaged.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1789.jpg)
Another view
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1792.jpg)
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Some videos,
Hopefully these will show just how well this set-up works,
Ralph, the motor moves, not the motor shaft. The shaft is fixed to the mill. You can use the other end to make a fitting to fix a handwheel to and it will work fine.. :thumbup:
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/th_MOV00068.jpg) (http://s401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/?action=view¤t=MOV00068.flv)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/th_MOV00067.jpg) (http://s401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/?action=view¤t=MOV00067.flv)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/th_MOV00069.jpg) (http://s401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/?action=view¤t=MOV00069.flv)
And this is the finish, the line was my mistake, I stopped the feed halfway though for some reason only know to myself. Just wish I knew what the password was :doh:
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1784.jpg)
The whole set-up is very rigid and secure. The idea is to fit a hand lever to move the motor and finish off with a proper cover to make it all nice and tidy.
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I forgot to say, That piece of ally is 3.5" long, the mill took 22min to pass over it, so almost 6.5 min per inch....
That seems slow enough to me, but then I've nothing to compare it to?
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Websterz,
I'm not sure I'd want to power a mill bed with a 170 DC motor, if something went wrong it's prob got enough power to do some real permanent damage.
Be better to have a motor with less power and have it stall or even burn out.
But, it would make a nice variable main motor, umm, now that would be nice.....send it to me, I'll make a power supply for it !!!
The drill motor is too fast, you won't be able to slow it down enough without it stalling unless you use gearing. Even the wiper motor is only just managing the real slow speeds. I have a feeling it would be better to gear it even though it is already geared. That way the motor speed can be doubled making it smoother running etc.
I'll see how it goes first though, others report they work fine and maybe I'm running it too slow anyway.
PS, you could build a power supply for that motor... :thumbup:
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Nice work Darren.
I'll bet you that MDF stays permanent. :lol: :lol:
Bernd
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Websterz,
I'm not sure I'd want to power a mill bed with a 170 DC motor, if something went wrong it's prob got enough power to do some real permanent damage.
Be better to have a motor with less power and have it stall or even burn out.
But, it would make a nice variable main motor, umm, now that would be nice.....send it to me, I'll make a power supply for it !!!
The drill motor is too fast, you won't be able to slow it down enough without it stalling unless you use gearing. Even the wiper motor is only just managing the real slow speeds. I have a feeling it would be better to gear it even though it is already geared. That way the motor speed can be doubled making it smoother running etc.
I'll see how it goes first though, others report they work fine and maybe I'm running it too slow anyway.
PS, you could build a power supply for that motor... :thumbup:
I tested the drill before disassembling it and my tach said I could sustain a low end of 20 RPM. With the finer feed control offered by the new controller I suspect that it will go at least that slow. If not I have a lovely selection of gears available. I can do as much as a 1:20 reduction just with what I have on hand.
hmmm...main drive motor eh... :proj:
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Nice work Darren :thumbup: I've been a little busy thinking on this stuff myself tonight..... Came up with a slightly different approach, not even close to finished yet!
I have found some of these on the circuit boards though.... 4 to be exact.
(http://i289.photobucket.com/albums/ll221/dividedhead/Random%20stuff/DSC03222.jpg)
Can you see them.... Black squares with the top right corner missing.... 4 legs and the little pictures on them like the flat square one you showed..... Stew, David.... we're sorted guys :thumbup:
This is where I'm upto in my "on the fly" design.... Just a few sketches on paper at the mo for the engage/disengage bit that Darren has sorted..... My motors are slightly different and mounting out of the back of the gear would be a bit harder (no spigot from the rear of the gears!)
Now this was marked out in true heath robinson stylee and I'm not apologising for it, it's functional and it works, it's just the way I do it ::)
Clamp the mill bearing onto the plate, draw around it to show if it moves and drill the holes through the existing ones, once marked remove the bearing plate and re-fit to the mill, clamp up the marked plate and continue to drill and bore all the holes you need into the plate.... fitted like a glove!
(http://i289.photobucket.com/albums/ll221/dividedhead/Random%20stuff/DSC03238.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/Random%20stuff/DSC03241.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/Random%20stuff/DSC03242.jpg)
New bolts to be purchased and a few bits to be cut away from the aluminium mounting plate (the bit with the squiggle on it) for the hand wheel to re-fit
That's it for now..... A (very) C-o-C of the intended design..... Sorry, it's late an I just scrawled it for you to see .
(http://i289.photobucket.com/albums/ll221/dividedhead/Random%20stuff/img075.jpg)
When the lever (far right) is moved to the right it will disengage the spline drive from the motor spline and pull the belt (might use a chain yet?) to the right by only 10mm or there about, not putting too much strain on the belt as it will be free wheeling on it's bearings when the hand wheel is rotated.
Right, I suppose I'd best get some sleep now ehh!!
Ralph.
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I don't pay attention to a thread for 1 day and it explodes! Looking good there Darren. I am impressed.
Eric
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Some very inovative cat skinning going on here. That is what it is all about, different methods ending up doing the same thing.
Well done to all.
Darren, I think your only problem is your flycutter shape and sharpening. The feed and speed you were going at should have had that ali plate like a sheet of polished chrome.
So a major good result for the feed, but could improve a bit on tool grinding. 9.5 out of 10.
Bogs
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I was thinking the same thing John,
Although the finish is much better than I was getting by hand it still could be improved upon. I too believe the tool grinding needs some more thought...I will work on it.
There are some other improvements that could be made to the circuitry...later when I've figured it out.
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John,
I've tried searching for that picture you put up with your flycutter shape, but I can't find it?
Do you know where it was? Or maybe put it here too when you get a moment :thumbup:
-
Here you are Darren.
http://madmodder.net/index.php?topic=850.0
John
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Thanks John,
I had another go and reshaped the tool bit a little to look like this
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1796.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1797.jpg)
The result was indeed a bit better, still getting some lines as you can see. Two bits of alloy, different finishes, I assume one is softer than the other.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1800.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1802.jpg)
Just practice and fettling now I guess. :)
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Looks pretty good to me Darren!!
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And me, if I was getting that standard I would be very chufed
:headbang: :headbang: :headbang: :headbang:
:clap: :clap: :clap:
:thumbup: :thumbup:
:wave:
Stew
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Ah yes, thanks chaps, it's not bad
But then I've seen Bogs flycutting, now that IS a finish...... :clap:
And he wasn't even trying...... :bow:
Mine is almost there, just a touch more to go, I believe it's in the tool grinding....practice, practice, practice.. :ddb: :ddb: :ddb:
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Looks pretty good from here Darren, I bet that looks real good in person? Photo's always make it look different to real life! (well I always look about 4 inches small!? :lol: )
I'll be more than happy to get rid of those damn deep lines you get when your hand goes over the top of the wheel rotation!!!
1 line every 10mm or so..... Does my nut in :bang: It takes forever to file, lap and polish the damn things out!
Looking forward to getting this thing made :thumbup:
Ralph.
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I think I'm trying too hard :scratch:
I had a look at some utube videos and everyone seems to be setting the feed much faster than I am, like a train in comparison.
So I reshaped the toolbit and this time honed it with a diamond stone.
This is the result, bit of tiny brass, sorry it's so small...that's a 1mm drill bit to give an idea of size.
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1836.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1839.jpg)
I noticed tonight how much the whole mill is vibrating (fly cutter is not balanced ). The mill is not bolted down and it's also on a flimsy table.
So I think I'll leave it at that for now till I remount the whole machine.
Ralph, if you come over Sat you can see it in action :thumbup:
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Darren,
I have many years of experience in sharpening cutters and setting feeds and speeds. What you are achieving here are your first tentative steps into precision machining.
Give it a little more time and experience, and all of a sudden, you will find that good finishes appear without even trying. I am not boasting at all, but that is the honest truth. From the time since you have realised you can do good work, rather than bodgit jobs, you are making remarkable progress, and that is no BS.
John
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Thanks John,
All this effort is an attempt to try some methods for building your engine. It may look like I've sidetracked, but not really. Just trying a few things before going for the real thing :thumbup:
Thanks for the compliment, from yourself it carries some weight... :bugeye:
I've said this before, I have struggled for some time with machining. Some pointers from all the guys here has really made it start to happen. I just watched and listened.
Monkey see...... :)
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Ralph, if you come over Sat you can see it in action :thumbup:
Yes I will and erm... Yes I will :)
That brass looks very good finish indeed.... Looks very nearly good enough to polish!? .... I really want a finish like that :ddb:
Soon, with a little help ehh Darren? nudge, nudge, wink, wink :thumbup: :wave:
I noticed tonight how much the whole mill is vibrating (fly cutter is not balanced ). The mill is not bolted down and it's also on a flimsy table.
I have some bits that might help a little with this? I'll bring some with me and see..... Without looking at the whole ass'y it's hard to know if it'll work? .... But it might and that would be good :D
We will see about it tomorrow :thumbup:
Ralph.
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Ralph, the finish on the brass is exceptional, if I could do ally the same I would be very happy indeed... :ddb:
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Well... I've since been to Darrens dungeon of cool stuff..... Oh yes, it's full of cool stuff :bugeye: :thumbup:
I've seen that brass and the finish is truely exceptional.... It'd polish without flatting :ddb:
We had the aluminium coming out pretty darn good too :)
I've got some bits n pieces from Darren to aid in my power feed, so I'll be posting the results here if that's ok? It'll keep it all together :thumbup:
I've got a lot of work to do, but it should be fun and will definately be worth it :zap: :borg:
More on all this later :wave:
Ralph.
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Right, After a quick private natter to Darren we decided that keeping all the power feed mod's together sounds good.... That said......
I've been a little busy :dremel:
You've already seen the plate I started to make (if not... it's further back in this thread!)
Well here is the continuation of that....
Motor mounting, first the 11.5mm hole for the spigot shaft to enter through, then the 3 mounting holes ..... Yes I know I'm a bad lad for the Heath Robinson way of marking and eyeballing, but it works for me most of the time!! As it did here. (I marked the hole points using the original motor mounting plate from the garage door op')
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03265.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03266.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03267.jpg)
Then I robbed another part from the garage door op' the spigot drive doofor thingy (technically accurate I think you'll find!?)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03269.jpg)
And two chain drive sprockets...
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03271.jpg)
I cut the plate next to allow me to get the hand wheel on whilst I worked out the placement of the rest of the parts..
Hacksaw and drill.... Then clean up with the mill and finally a file to remove all 90degree edges.
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03273.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03275.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03277.jpg)
I then turned my attention to the sprockets... Drilled out the centre of the smaller one and loctited a 10mm stainless bar into it, machined the end to accept the spigot drive doofor thingy and loctited that on to the end of the sprocket.
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03280.jpg)
The larger sprocket was bored out to accept the handwheel hub.
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03281.jpg)
and then the dial was re-sized to allow fitting of the whole ass'y.
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03283.jpg)
This is what we're left with...
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03285.jpg)
Then a bearing for the shart to allow pulling of the freely rotating shaft
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03287.jpg)
And finally for last night...
Engaged...
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03288.jpg)
Dis-engaged...
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03289.jpg)
:)
Bit of a monster post, but I had a lot to show :thumbup:
Next time, a chain and a little release mechanism for the spigot drive doofor thingy!
Ralph.
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Nice job Darren
:thumbup: :thumbup:
I can see what you were explaining about the handle on your mill making things awkward.
On the face of it it will be easyer on my mill.
Stew
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Her's a question
:scratch:
As my machine has an handle at one end and the facilties for a drive at the other would it harm if I had the motor permeantly engauged ?.
Stew
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Her's a question
:scratch:
As my machine has an handle at one end and the facilties for a drive at the other would it harm if I had the motor permeantly engauged ?.
Stew
Heavily geared motors Stew.... Most unlikely to work! try turning it with a nut on the end of the shaft.... Should make it really clear!! :thumbup:
Darren,
Much easier on your mill!
I'll get it done, even if I have to re-design the drive!! :thumbup:
Ralph.
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Stew, don't try to turn the shaft by hand, you might strip the teeth off the big gear.
Unlikely by hand, but you could probably do it with a hand wheel attached, like on the mill. :thumbup:
Hence the disconnectin thingi bob wotsit
One gear is a worm wheel
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OK Thanks for putting me straight Chaps
I'm not planning on doing anything just yet, Johns got some toothed belt drives for me to look at that may do the job.
Stew
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If they are permanent magnet motors you'll create a current trying to turn the shaft. Might not be good for your electronics. Could cause voltage spikes. Plus the faster you try to turn the motor the more resistance.
For an experiment take a DC permanent magnet motor and tie the two leads together. You'll feel the resistance of trying to generate a current.
Bernd
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That's the back EMF I was talking about before.
I decided that it wouldn't be a problem in this situation for two reasons.
a: These types of motors stop dead when the power is switched off.
b: By using a center off switch we have disconnected them from the power supply completely when the switch is off.
Point to note about permanent magnet motors, they make very in-efficient generators, you really have to spin em fast to be of any use.
Better to use a field coil type motor I believe. 3 phase types can be very good.
-
Well.... This should be interesting to some of you?
Since it was a bank holiday today I decided to have a go in the shop.... Not good weather and a day for free :)
So we left it needing a bit of a lever for the engage/disengage.... Well here's what I've been upto...
Bore a short adapter for holding a flanged bearing.
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03296.jpg)
Make a rear part to the bearing housing then cut a slot in it and cross drill, tap one half M5 and drill 5mm clearance through the oter half.
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03298.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03301.jpg)
(plasticcy aluminium!!)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03302.jpg)
Cross drill then shape and size (to 12mm) a mild steel bar
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03304.jpg)
Cut the 8mm slot in the bar (made over length since I was making this up as I went along!)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03309.jpg)
Narrow the bar for the slot on the bearing holder to fit.
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03311.jpg)
Make the mounting for the lever..
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03307.jpg)
Mount the lever pivot mounting
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03312.jpg)
Cut and turn down the driveshaft to take the bearing (tapped M4 into the centre to hold the bearing on, not shown)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03313.jpg)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03314.jpg)
A quick and rough assembly of all parts... (Handle not cut to length and the allen bolts are to be replaced with purpose made 5mm bars threaded only where needed)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03315.jpg)
Finally a couple of short vid's. Using the CB power supply donated by Darren (not yet modified) just to check it all works....
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/th_MOV03319.jpg) (http://s289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/?action=view¤t=MOV03319.flv)
Got to swap the split link round... it's too deep on one side and occasionally catches the post! (the other side is the same depth as the rest of the chain)
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/th_MOV03318.jpg) (http://s289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/?action=view¤t=MOV03318.flv)
Hope that shows this will work :thumbup:
Ralph :borg:
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Yup! I believe that shows it will work most definitely. Very good.
Eric
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Thank you Eric :thumbup:
Just the electric trickery to figure out now..... I'm going back through the post to see what Darren wrote :coffee:
Ralph.
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I think that is really something you have done there Ralph. :clap:
With the gearing you should be able to keep the motor turning faster and therefore smoother.
One thing to watch, my power supply has given up the ghost. It seems that although they are capable of producing up to 24V the components inside are not.
Something I overlooked was the voltage rating of the caps, mine are rated at 16V and whilst I've been running at mostly 5V or so the occasional burst of higher has cooked them.
No problem, I'll swap em out, but just be careful with yours and have a look at the cap ratings.... :thumbup:
-
Thanks Darren :)
I'll investigate the electrics thursday or so..... Should be interesting :zap:
Ralph.
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Nicly Done Ralph
:clap: :clap: :clap:
I'm taking all this in for when I do my mill.
Stew
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Cheers Stew :thumbup:
Yours shouldn't be half as complex as this one.... you guys and your two handled luxury ::)
Pool tonight :) Better win this week!!! :bang:
Ralph.
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Super work Ralph!!!
-
David, Much appreciated :thumbup:
You can have a go at your veriety of mill' as soon as we figure out some workings and send you the motor parts :dremel:
FYI....(just because I mentioned it above) Personally lost my pool match :( But the team won :D
Ralph.
-
Ralph, how did you make the curves on this piece?
(http://i289.photobucket.com/albums/ll221/dividedhead/machine%20mods/Milling%20machine/DSC03311.jpg)
-
I spent yesterday repairing my power supply, back up and running now :)
Also I dug out another unit and modded it for the purpose of making a donation to a needy cause. Spent several hours on it only to watch an op-amp fall off... :bugeye:
All the legs had rusted through, 8 of em. I have found a source for some new ones but at 8 quid each and a min order of ten it's a no go. Shame, it was a really nice power supply at 8 amps.
I'm going to have another dig around today to see what I may be able to find.
-
Ralph, how did you make the curves on this piece?
Eye hand coordination :dremel: :) (Did the same kind of thing on my camera mounting http://madmodder.net/index.php?topic=285.0)
Normal end mill (top of pic) and controling the wheels.... Not that easy... I quite often get confused right at the end and drive the cutter the wrong way :doh:
Plan is, very small movements till you know which way your going!!
Worked quite well this time though.... Didn't need them.... It's a way larger slot than needed, but it looked better with them :headbang:
What's the op-amp look like, numbers etc... I have many circuit boards here with bits on.... Is there nothing suitable on the boards I left with you?
Got to be able to find one for less than 8 notes??
Ralph.
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I see, in that case well done.... :clap:
Don't worry about the op-amp, I've decided to start fresh and build a circuit from scratch using all new parts.
I've built the circuit, well two of them, and have been testing them for the last couple of hours. I had one with two motors running to make sure it could handle the pressure.
worked fine I'm glad to say. :)
I'm actually building them for my valve amp and wanted something small and tidy. But they will work the motors just as well, in fact they have been :ddb:
Low part count, easy circuit as most of it is in the chip and even that only has 3 connections.
Bits you have as follows....
one rectifier, two caps, one transformer
Bits you don't have
one 1k lin pot, one chip LM1084 rated at 5 amps,
You will need something to mount it on and some wire, which you may have...
There really is nothing to it if you are interested I can give more details. It will run 12 & 24V motors.
Mine need to run at 10A each for the valves, so I'm sticking a 2N3055 on the end, well a pair of them in fact. You can do the same, it's simple enough and would help the LM1084 to run cool instead of hot. But it can take it. Besides it has it's own build in protecting circuit so you can't damage it anyway.
If that all sounds too much, don't worry I can show you step by step if need be, I can always build another one and do a post a day for each component with pictures :lol:
When you have done it once you'll find all sorts of things you want to power and make some more...... :ddb: :ddb: :ddb:
-
Congratulations.... You've just talked yourself into a mini how to post about making this circuit :thumbup: :zap:
I'll be eager to read it by lets say Friday evening :lol:
Well ok, when ever.... But I am interested... As I'm sure David (TS) and Stew are :thumbup:
If you link to the parts etc that would be good too :thumbup:
Ralph. :ddb:
-
Ralph,
You forgot the bit about making them and posting them to everyone. :lol:
-
oh ek....... :lol:
Well if anyone really gets stuck I will, hows that?
But I want to see you try first...does that sound fair....... :ddb:
-
Fair Enough.
Stew
-
Here you go, all the info you could ever need in this pic
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1997.jpg)
:lol: :lol: :lol: :lol:
Messy bugger arn't I :lol:
It's powering two motors there as I write this post, prob been running 3 hrs now.
Ok, this is it, all that's needed is to connect the transformer and pot and it's done
(http://i401.photobucket.com/albums/pp92/thebodger/Sealey%20Milller/Power%20drive/IMG_1995.jpg)
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Ok, so that I can do.... Does it have to be that messy?
I'm sure I can tidy my bench up a little if it has to be the same! :ddb:
Seriously, I have some vero board here that has been knocking around for a few years it certainly would suffice.
I just need the relevant info and a quick circuit (what goes to where) diagram and I'll be off :thumbup:
Good work that man.... And it's only Wednesday!! :nrocks:
If we organise the list and who wants what and where the bits go then I'll be happy to put circuits together too :zap: I can solder quite efficiently, I just need to know what I'm soldering where!
I'm liking where this thread is going :thumbup:
Ralph.
-
I'm having a bit of a problem, Looking around to order some parts...
I have used a LT1084 adj regulator, they used to be two a penny avail almost anywhere.
Now most electronics outlets have dropped them and I can only find them for around 8-10 quid a go.
For a chip on its own that is just plain silly, you might as well buy a ready made module....
50p each would be reasonable. I'll keep looking but if anyone can recommend an alternative please speak up :ddb:
The only other way would be to use a LM317 with a 2n3055, but I've never liked the 317's cos they are so finiky.
I'll keep looking......
-
I've got a LM340T5 and a UA7812C on a circuit board in my hand..... Any good? I don't know what they do?
I'll check for more tomorrow :)
Ralph.
-
The first one is a 5V regulator so no, dunno about the second.......have to look it up
But, I've just bought ten LM338T's, never used them before but I think they will work....otherwise it's a different circuit and I know this one is reliable cos I've used it for years.
Fingers crossed..... :ddb:
-
Ralph, the second is a 1.5A 12v reg, useful, but not here. :thumbup:
-
OK Gang.. I see some awesomely good designs.
I LOVE my power feed on my mill. I was kinda indifferent when I got it, because I had no idea how useful it was.... Until I cut dovetails in the 34" long tool steel plate I am getting ready to divvy up for new tool holders for the lathe.
SOOOO
Here is the question.
Why not put a ratchet mechanism in the drive? Like the head of a 3/8" ratchet?? SO that while feeding.. If you are not close enough to the work after a pass.. you simply hand crank it closer. WHen you stop, if the ratchet mechanism is set properly, it will feed with power.
If you feed in the other direction, it simply ratchets, and has no load. So you could feed across a part.. then hand crank it in the other direction fast, and it would simply free ratchet.
I know of a type of drag racing transmission.. and I forget the name.. but IIRC it is similar to a helicopter transmission in that it only transmits power under load. Once the engine quits, or slows.. the transmission disengages and the vehicle or blades free wheel/spin.
Scott
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Hey guys...
Just read up on this...some good stuff..
One thing though I noticed..there's a theme running through this thread...
You are all running with a voltage regulator of sorts to power the motor for differing speeds....
Sorry but its the wrong way to do it...The lower the voltage the lower the torque from the motor...
Answer...use a pulse width modulated supply...
Arrghhh whats that you say?
Well its a bit of magic elecriccery that pulses the motor with the full supply voltage for a short period of time to make the motor go slow or applies the full supply voltage for a long period of time to make it go faster....
Want proof?
Easy....Take your motor and connect the wires across a car battery...hold them there for a minute or two...the motor runs fast yes? now flash one wire across one terminal or just dab it on and off...the motor now runs very briefly and soesnt run up to full speed but still has full power from the battery..... and max torque too...
I could cobble up summat if anyone wants.....
-
I'm with you here John,
Although in practice lower voltages and torque don't seem to cause any problems, the motor still turns and the table still moves smoothly. The reality is that very little power is needed to move a mill bed. Even the bigger machines use small motors. Then you have to factor in the gearing ratios that keep the motor speed up whilst the output shaft speed is low.
However, I personally would like to see what you have in mind as the alternative.... :ddb:
-
I would tend to use a 555 timer configured as an astable with variable mark/space ratio to give the pwm..Use a mosfet as the power driver device...something like an IRF 540...cobbled together the parts should be less than a fiver excluding tranformer etc...
Need the drawing? no probs..
I just bought a wiper motor from Ebay for £12...from a Ford Fiesta...that ought to do it..
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=290325646440
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I have a question John....
If say you wanted half speed, you would set the timer to pulse the power delivered for 50% cycle time...
Wouldn't 50% on 50% off at full power be the same as 50% power continuous ?
eg, take 1HP for simplicity sake, 1/(100/50)= 1/2 power/torque
Also what about this pulsing power, I realise the freq would be high, but it would be pulsing all the same wouldn't it?
-
I have a question John....
If say you wanted half speed, you would set the timer to pulse the power delivered for 50% cycle time...
Wouldn't 50% on 50% off at full power be the same as 50% power continuous ?
eg, take 1HP for simplicity sake, 1/(100/50)= 1/2 power/torque
Also what about this pulsing power, I realise the freq would be high, but it would be pulsing all the same wouldn't it?
I'll answer these as best I can...I dont hold and engineering degree or Phd in electronics, I'm merely a hobbyist..
Answer 1..yes 50% would equal 1/2 speed assuming say the motor ran at 3000rpm at full volts and disregarding losses in the motor.
Answer 2...Seems logical to me captain..but because you are applying the full 12volts then the motor runs at its max speed for a short duration that the power is on to it...The following probably describes thnigs a bit better
To control the speed of a d.c. motor, it needs a d.c. power source.If you take a 12v motor and switch on the power to it, the motor will start to speed up: motors do not respond immediately so it will take a small time to reach full speed. If the power is switched off sometime before the motor reaches full speed, then the motor will start to slow down. If the power is switched on and off quickly enough, the motor will run at some speed part way between zero and full speed. This is exactly what a p.w.m. controller does: it switches the motor on in a series of pulses. To control the motor speed it varies (modulates) the width of the pulses - hence Pulse Width Modulation.
See the waveforms in the pictures I've attached... If a motor is connected with one end to the battery positive and the other end to battery negative via a switch (mosfet, power transistor or similar) then if the mosfet is on for a short period and off for a long one, as in A above, the motor will only rotate slowly. At B the switch is on 50% and off 50%. At C the motor is on for most of the time and only off a short while, so the speed is near maximum. In a practice the mosfet is switched at something like 20kHz. This is too fast for the motor to even realise it is being switched on and off: it thinks it is being fed from a pure d.c. voltage. It is also a frequency above the audible range so any noise emitted by the motor will be inaudible.
I hope this answers your questions without insulting your intelligence...Some of this you may already know..
-
Hi John,
Yep that does it nicely... :thumbup:
As you know I already have a power feed set-up on my mill and use it quite a bit now that it's there.
If there is a better way of delivering the power then I would certainly consider a change. At the mo I'm yet to be convinced.
My thinking is with a windscreen motor the worm drive gives quite a large gear reduction ratio, so the motor is not turning particularly slow at the lower speeds.
My other finding is that the lower speeds are not really of much benefit in real life and I tend to use it flat out 99% of the time.
Half speed can sometimes give a slightly better finish, but not for everything or every type of tooling/material I have used.
I think too much effort has been put into designing a precisely variable speed (voltage) output on my part. But this of course in in hindsight.
Two speeds, one at 5V and another at 18V would be more than adequate in my opinion. With this in mind I'm thinking an old computer power supply with 12V & 5V outputs would be more than sufficient for those electronically challenged. It's prob the way I would do it now if I had to start over.
A 9/18V transformer and rectifier would also be a very simple, cheap and reliable way to do this too. Don't worry too much about the exact voltages, it really is not that important :thumbup:
Oh, and these motors seem to be quite happy to run at 25V without any signs of distress too....
I hope that helps.. :dremel:
Any chance of the schematic, I've never used a 555 but I know what it is... :ddb: