MadModder
The Shop => Tools => Topic started by: pmdevlin on December 17, 2014, 11:48:21 AM
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Hi all, I will set the scene! I'm pretty new at model engineering, and need some desperate help. I don't even know if I am posting the correct place, mods please move if applicable.
I was today using my micro mill, low rpm, milling some plastic sheet, so no problems here. I bought this off a friend, a very talented engineer, and a regular on this forum, he passed away last year, so my predicament is that I cannot go back to him to talk about the mill he knew inside out. It had been modified to suit his disabilities, it is belt drive, and the control panel was moved away from the machine so he could reach it. I believe its a seig machine, they are the instructions he gave me with it, although it has no markings on it. All I can say is he only used good stuff!
So after a bit of use, the fuse in the control panel blew, I changed it, it blew again. I have inspected the motor, taken it apart, all is good, no binding, brushes good, no signs of excessive heat,. all windings seem to be ok. The connecting block between the control panel and machine is good. Reassembled, fuse blew again.
So, with control panel disconnected from the motor, I can turn on, and turn up potentiometer, nothing is amiss. When connected to the motor, the motor immediately spins up with the potentiometer in the off position, and the fuse blows. I assume with potentiometer in off position, motor should not spin up?
I have inspected inside the control unit, all appears to be fine, and no smell of electrical death! I am now at a complete loss as I have absolutely no knowledge of how the control panel works, what to test, how to test, and what to do now please help! I am thinking the control panel is faulty, as its been modified the manufacturer will be no help, can anybody suggest a repairer or is the mill now finished!,
Many thanks
Paul
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I am assuming you are in the UK
Get a 100watt lamp old fashioned type a lamp holder and wire these up instead of the motor ,leave the motor disconnected , now if the fuse blows it's the controller if not it's likely the motor
Note you can get the bits from arcurtrade or amadeal but if the motor is duff and you put a new controller in it most like will go kaput
It may be simpler if you are not sure to replace both at the same time
Stuart
Edited to include more info as requested below
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SNIP
Note you can get the bits from arc ... SNIP
Stuart
Hi there, Stuart,
You know what you mean by 'arc' and I think I know what you mean but does Paul? I suggest you elaborate.
Hi there, Paul,
Your photos are reader-unfriendly - much too large. I suggest you go to the 'Gallery' section and read about re-sizing photos.
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hi Paul
Check your PM and posting on HMEM Eric
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will do Eric, yeah just clicked on the photos and they are massive, sorry. I am familiar with arc euro trade thanks for the pointer, I cant replace both components, way too expensive, too expensive even for one of them, hence needing a "fix"
I will do lamp test, and suggested motor test by pm, and report back
Thanks
Paul
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What type of fuse are you fitting?. It may need an anti surge one. You can usually tell by looking at original and seeing if it's a empty glass tube or if it's filled with white powder. If the latter its anti surge.
Matt
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its the glass tube, I assume its the correct one as its been fine for over a year. Instructions say its an X1 Super micro mill
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When connected to the motor, the motor immediately spins up with the potentiometer in the off position
Strongly suggests that the controller has failed. If the motor is spinning up, chances are that the motor is OK.
Can anybody tell me if it is an AC or DC motor and what the voltage range is? Is it on a plate on the motor casing?
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The X1 mill is powered by a 150 Watt dc motor. This motor has a voltage rating of 180 V. It has an DC electronic controller with feedback via a current sense resistor to help maintain a constant speed characteristic with varying load.
Mike
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Would this controller from ebay do the job? The output would need to be routed through a reversing switch.
http://www.ebay.co.uk/itm/Rotary-Knob-Adjustable-Motor-Speed-Controller-AC-220V-Input-DC-180V-Output-/290933673054?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item43bcff8c5e
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Would this controller from ebay do the job? The output would need to be routed through a reversing switch.
http://www.ebay.co.uk/itm/Rotary-Knob-Adjustable-Motor-Speed-Controller-AC-220V-Input-DC-180V-Output-/290933673054?pt=UK_BOI_Industrial_Automation_Control_ET&hash=item43bcff8c5e
I think this would work although the description does not give any indication of the current or power rating. However, this type of controller is usually designed to cope with several amps so I think it would be worth the risk.
I doubt that the controller has ant provision for feedback to maintain constant speed regardless of the load but this may not be so important.
Mike
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I really appreciate the help all, its very encouraging.
Following some suggestions (I posted on hmem then realised this was the UK site) I connected a 240v test light to the controller. Turned it on, holding my breath! the test light lit (60w bulb, very bright) I turned on the potentiometer, and the bulb light remained constant throughout the range. I was pleased thinking this means the most expensive item is ok, but is it? Should the bulb have lit with potentiometer turned off (meaning nil rpm for motor) or am I being stupid.
I then connected the motor to a 12v dc feed (don't know if its a dc or ac motor). The motor did not work, however I could feel "resistance" when turning the shaft by hand, which went if the motor was disconnected from the 12v feed. No hot wires suggesting a short. I stripped the motor again and inspected under an LED magnifying glass, I cant see anything wrong with windings etc.
Don't know if I have achieved anything doing these tests, any thoughts?? Thanks for the ebay link, I can breathe more easily now there is a potential fix at budget money : :mmr:
Again, many thanks, keep the suggestions rolling in, I need a cheap fix!
Paul
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I replied on the other forum, but I can repost here as well. All my problems with my micro mill were solved by replacing the speed control pot.
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many thanks, sorry we are diving between the two forums.
By speed control pot, is it this (depending on which board I have)
http://www.arceurotrade.co.uk/Catalogue/Machine-Spares/Super-X1-Spares scrolling down to the SX1-124 Potentiometer.
The control unit from ebay suggested previously, I have no real need for reverse, not use it in 18 months, so I would assume its an easy wiring up job? It has been suggested that 12v on the motor would not be sufficient to spin it up, and the fact the bulb was illuminated with pot turned off suggests its the control unit, as it should have gone brighter turning up the potentiometer?
So I was thinking, if the pot is faulty, should the motor not just run at a constant speed, or not at all? back to the beginning, it runs for a second or two then pops the fuse.
Whilst on the subject of fuses, I anticipate I will be blowing many more before its fixed, and only have 1 left, can I use something like this
http://www.ebay.co.uk/itm/ABB-S201-1-POLE-MCB-CIRCUIT-BREAKERS-2-4-6-10-16-20-25-32-40-AMP-/321302757144?pt=UK_BOI_CircuitBreakers_RL&var=&hash=item4acf22ff18
Thanks
Paul
I need to find someone with electronics experience!
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well I have found a local electronics engineer, and have dropped off the motor and control unit for testing. I'm back in work tomorrow so this threads might go a bit quiet for a bit
Paul
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I believe that is the correct one. I bought mine from Little Machine Shop, and they knew which one to send. It has been a while, so I'm just going from memory.
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Other people have used this item number from eBay to replace the speed controller with success
181473818094
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well I'm in a mess now, don't know what to do. The motor has been tested and reported to be burnt out. I took the motor apart before giving in to be tested, and could not see any evidence of this. The guy has connected up to 110v ac to test it, on the basis that the motor has a big spec sticker on it, and it does actually say 240v ac, however, on the arc euro site, the replacement motor says its a dc??????
He says the motor ran for a very short period, then gave up, and a possible short was causing the fuses to blow and the motor to spin up without potentiometer input. I'm confused? I thought it was a DC motor, so why on the big sticker on the can it does clearly say its AC?
So no further on really, except now I need a motor, and might still need a control board, anybody got any recommendations for a direct fit motor other than a massively expensive £88 from arc euro, and that might not even be the fix!
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Firstly, sounds like the controller board is u/s, with the pot in the off position there should be no power to the motor light bulb whatever....the fact that the lamp lit as soon as power was applied suggests the mosfet on the board has died....A fairly easy fix IMHO....
Secondly, the motor is definitely DC if it has brushes and magnets.....no field coils...would confirm this.
If connecting the motor to an ac source then damage to the motor will occur, the alternating field setup in the armature would cause it not to rotate......
Where abouts are you?
Any where near Hull?
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The guy you took that motor to test did not know his stuff and he should foot the bill because he has burt out the motor not you
Let me explain ,
I am a time served Sparks and have done some time in armature and stator winding when I gave up work I was an electrical engineer to PhD level
Ok back to your motor a universal motor has a series field coil not a perm magnet one, when the AC volts reverses as it does 50 time a sec the field does along with the armature and every thing is in step so it's ok as it is on DC .
Now with a perm mag field it cannot reverse but the armature field will hence it no go and it will release the magic smoke alas it will not be able to be refilled.
I would bite the built and get a new motor and controller from one of the dealers then you will know it will work. But please do not let that guy anywhere near it
Stuart
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The guy you took that motor to test did not know his stuff and he should foot the bill because he has burt out the motor not you
I would bite the built and get a new motor and controller from one of the dealers then you will know it will work. But please do not let that guy anywhere near it
Stuart
Lol @Stuart..... :lol:
I agree, it's gonna cost you....dearly...sadly.
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The guy you took that motor to test did not know his stuff and he should foot the bill because he has burt out the motor not you
I would bite the built and get a new motor and controller from one of the dealers then you will know it will work. But please do not let that guy anywhere near it
Stuart
I 100% agree ! Permag motors are DC devices.
Someone, I think it was John suggested that the power FET in the controller had gone (short circuit), replacing it would be an easy and cheap fix.
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Ok.....
I'll stick my neck out here and offer to repair the controller... :zap: :zap:
I have the technical know how and the means to test...( trumpet fanfare .... :lol: )
Paul if you want to take me up on my offer send me a pm please...
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Thanks John, (and others!) Ill take you up on it please, I am Wirral, I will PM you, and will naturally pay for services, successful or not!
I have challenged the guy but he keeps coming back with the fact it has a big spec sticker on the motor, and it says "AC". I too also think he has fried the motor, inadvertently, but as he is the "expert" should he have known this? .
So, just to get it straight in my head, I will be picking up the controller and motor tomorrow. I understand the inside of a DC motor, or at least what it looks like. Would an AC motor be visually different externally? If so, Ill push for him to foot the bill, but I doubt I will be successful if it looks the same externally. (back to the flippin AC sticker on the can!)I would have thought in my simple way, he could have plugged the controller in to power,, turned on the pot, and measured what was going on at the output lead that was for the motor. I was very specific with my description as to what had happened, then surely he would have seen the output was DC, not AC?, and would have been able to assess if the board or pot was faulty.
Unfortunately he would not touch the board as he wanted a circuit diagram, so I have gone backwards really, to the tune of £88 motor, surely there are cheaper alternatives out there?
Paul
PS sorry for duplication on hmem I originally started over there and as there have been responses for courtesy Ill keep posting
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Paul,
Pm sent....
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received thanks John.
I've been doing some internet trawling, and it appears there is a sieg mill with an ac motor, who know's what I have! The instructions that came say super X1, yet all sieg are red, mine is green, and has a belt drive conversion.
I will photo the damned motor sticker tomorrow, it might help with all my ramblings!, must be frustrating to you guys when an idiot arrives, like me! :hammer:
Paul
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I have challenged the guy but he keeps coming back with the fact it has a big spec sticker on the motor, and it says "AC". I too also think he has fried the motor, inadvertently, but as he is the "expert" should he have known this? .
I agree with you. But as an "expert" he does have a duty of care. Did he charge you any money ? Did he give you a work sheet ?
I think that you will find that the label on the motor refers to the combination of both the controller and the motor. Unfortunately I have seen and used motors that use "AC" but look very similar to "DC" ones. Without knowing what to look for it would be easy to mistake one for the other.
I was very specific with my description as to what had happened, then surely he would have seen the output was DC, not AC?, and would have been able to assess if the board or pot was faulty.
Unfortunately he would not touch the board as he wanted a circuit diagram, so I have gone backwards really, to the tune of £88 motor, surely there are cheaper alternatives out there?
Paul
I'm afraid that his refusal to have anything to do with the control board and wanting a circuit diagram, would have rung alarm bells with me, and I would have quickly walked away.
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I'm afraid that his refusal to have anything to do with the control board and wanting a circuit diagram, would have rung alarm bells with me, and I would have quickly walked away
Unfortunately I only found this out today on the telephone. I have a plan, tomorrow I will get him to confirm the output, from the control board he will then have to confirm if output is dc or ac, lets see1
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Paul,
Just to satisfy my curiosity, could you post a picture of the label on the motor please?
Peter
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motor has been collected, I will collect controller later, I have insisted he checks output, to satisfy me its either ac or dc, and the pot is doing something!
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Ok
First pic is the tag for the mill as a unit
The last pic clearly states its a DC motor so your expert burnt it out QED
Stuart
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Yep the big sticker is ratings for the entire mill as a unit. Main power input to mill is 220-240v AC. Motor doesn't have a mt2 spindle taper. Pretty obvious smaller sticker is the actual motor spec and it's clearly DC. If you look above the cable on the first picture you can see the end of the brush cap ( round black thing with a screw driver slot). AC motors don't have brushes. He's fried your motor and should pay for replacement IMO.
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Yep the big sticker is ratings for the entire mill as a unit. If you look above the cable on the first picture you can see the end of the brush cap ( round black thing with a screw driver slot). AC motors don't have brushes. He's fried your motor and should pay for replacement IMO.
Ahhh. But universal motors have brushes too....have a look at your Bosch electric drill/planer/ sander.....
A typical DC motor is either perm magnet or separate field coils energised with a DC supply....not connected in any way to the brushes....(a universal motor has the field coils in series with the brushes typically...)
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just found the motor at arc euro, its a dc motor, so I have to agree, he has fried it, by reading, like me, the main sticker, now its been pointed out, its clearly for the mill, not motor, so original fault lies with board, or pot, and I bet its the flippin £5 pot!
So its back to him later, and arguing the point, I hate this confrontation, I'm an honest easy going guy and expect same back, hopefully he will realise his error when he tests output of controller and does the right thing by me, hmmm, not holding my breath!
I have identified the board from serial numbers on the pics shown on arc euro site, looks like NOBODY else sells these motors or controllers, Hopefully John can save the board!
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Forgot about universal motors as it's not something I tend to come across tbh. But his motor is clearly labelled as DC, so still think his expert is at fault.
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Paul
Be careful with your expert he no doubt come back and say the controller is outputting AC , but it's pulse width DC
No doubt john can explain more eloquently than I but it's output is on for a time and then off for another time period , eg on for 50% off for 50% gives you approx half speed , that's what the pot does it varies the on off ratio hence the speed .
Note the volts remain the same but it's only switched on for a short time for low speed and on for longer to give higher speed .
To test you need a load and an oscilloscope
Stuart
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I suggest that before the motor is written off a burnt out / fried, it is tested to check that is indeed the case.
Putting AC into a DC motor will only damage it if the stall-current - time integral is sufficient to raise the temperature inside the motor to the point where there is some critical damage (such as loss of insulation or commutator distortion).
What the PM DC motor does if it is fed AC depends on the nature of the input, the electrical characteristics of the armature, the mechanical time constant of the armature, the thermal properties of the system and, to a lesser extent, frictional forces. A typical response is that the armature will vibrate at 50Hz - it will hum happily to itself (until it burns out, if it is going to).
If the AC has only been applied BRIEFLY then there is a good chance that the motor is OK (remember that if he has tested it a 110V AC then he has put less power into it than its 240V DC rating). You could test it by carefully connecting it to a 12V car battery and a fuse which should be enough to get it turning. (NOT via the cigarette lighter in your car, just in case!). If it turns its probably still good. If it doesn't turn its definitely :(
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Yup I agree with Pete,if the applied ac source was on for a brief period then theres a fair chance it might have survived the ordeal... :zap:
A little more than 12v dc will be needed tho' to get it to spin up.....24v more like...
This where a variac comes in handy...( with a bridge rectifier of course...) for testing....
Growler testing will reveal any probs with the windings...
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Good grief there John not heard the term growler for a long time .
We did not call them by that name in the winding dept but the name is very not PC now
Coil and a hacksaw blade it what we used a long with the normal drop test and IR of course
But we only did DC motors to about 100hp but the converters 6 phase in DC out were about 500hp with open knife switch starters
I hope I have not confused Paul with my ramblings
Stuart
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ha ha, I was confused the minute the fuse popped! Stuarts comments regarding pulse width are going to make things very difficult for me regarding any recompense for the motor, if indeed its burnt out, I reckon he will still insist its ac output so I am snookered really.; I do think he is a genuine guy and is probably making a huge mistake without knowing, anyway, I'm off to get the controller now, if he says he still hasn't touched it its coming home anyway, for a destination close to the East coast.! :mmr:
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Paul you don't need to let on you know how it works just hope he don't read this forum.
John will fix you up
The controllers do not output AC just lumpy DC 😳
Good luck and be safe remember you cannot see it nor can you smell it but you can feel it
Has as been said unless the magic smoke was let out of the motor you should be ok
Stuart
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motor has been collected, I will collect controller later, I have insisted he checks output, to satisfy me its either ac or dc, and the pot is doing something!
That first picture refers to the machine the motor is fitted to ! The third one is the motor specifications.
Your expert is both blind and stupid.
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went back, as arranged, he had shut up shop and gone! Now I know its New Years Eve and all that, but he knew I was coming back, he could have just rung me, so he got the voicemail from Satan himself!
I've told him (and will ring him after holiday) he has cooked the motor, and I want the controller back, assuming he has done nothing as I could see it through the window in exactly the same place I left it :hammer:
I've put 12v on the motor, don't have a 24v source, it was def trying to turn, Stripped it again, cant see any damage or evidence of burning, no smell, nothing out of the ordinary, maye I have been lucky!
Happy New Year, nad a massive thanks to all contributors to this thread
Paul
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I've put 12v on the motor, don't have a 24v source, it was def trying to turn, Stripped it again, cant see any damage or evidence of burning, no smell, nothing out of the ordinary, maye I have been lucky!
Paul
Is your 12v supply portable? You could try hooking it up to your car battery to give you 24v...(just be careful not to short anything out.... :zap:)
Otherwise you could use your battery in conjunction with a 12v bulb wired in series to prove the continuity of the windings by going across each pair of segments on the comm....
Shout up if you need a bit more of an explanation....
Off to the electronics section now to read replies on my pc issue... :doh:
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picking the controller up in a few days, After lengthy phone conversation, he has agreed if I can prove its a dc motor (well its got a sticker on the can!) he will take responsibility.
To be fair, I will do Johns test on the motor, so, just need an idiots guide as to how to do this! I assume if bulb goes out on any segment, then the motor is actually duff?
Paul
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Paul
To keep all your fingers :D get a 3 volt battery and a 3 volt lamp
Connect up battery lamp motor and back to the battery all in a long chain turn the motor by hand very slowly ( it will be better one way) and watch the lamp it may flicker but as you have thought out any dead segegments are bad news
The reason for three volts is there is no possiblity of the motor turning , thus safe
Now this is not the way I would do it I would do a volt drop test on the armature but that requires more equipment , or a growler test , that uses a coil with lamination fed with AC and held on the armature laminations a old hack saw blade held on the other side will rattle if a short is present
As a last comment if it looks ok and smell ok it should be OK if he did not leave it on AC for long , it would have made a loud hum and not rotated , henc his misinformed diagnosis due to fault testing methods
Hope you get it sorted with a little impact to the wallet
Note I refer to lamps it's because they go in lamp holders and bulbs go in the garden , remember the clout round the ear hole in 1962 when I started work at the tender age of 15
Stuart
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collected the control panel today, and its on the way to Hull! :headbang:
Having proved its a dc motor (sticker on it!!) expert has kept it to test on high dc voltage, if faulty he has agreed to replace. He confirmed he used the large micro mill spec sticker thinking it was referring to the motor.
Hopefully all will work out ok!
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Yup,I'll let you know when it gets here and what the problem is.... :zap:
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Keep us all informed John, we are all on the edge of our seats.
If its an MXT-2325 board like mine, I'll have spare diodes and thyristors.
Pete
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motor is back with me now. The guy wanted it tested on a higher dc voltage if he was to replace as promised. A fair request I suppose, however, no test can replicate the voltage and load this motor is designed to take. It was tested on 60v dc, with variable supply, he borrowed something to do it, I watched! It ran from a virtual stall speed, up to what the 60v could deliver in terms of speed. Even at low speeds, it was impossible to hold the shaft by hand, so the torque was certainly there. No heat, no smoke, it ran for some time, so I had no option but to agree he got off the hook :D
If John has some luck with the controller, it will be a nervous time turning it all on again, I hope the motor is actually ok, he says it ran only for seconds on ac so I think we should be ok. I have stripped it again, no signs of damage, heat or any smell of electrical death!
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Looks like you got the pass jail card , glad at least one part is OK
I also is good that his mistake was admitted to and you had a good outcome , maybe though he should get an appointment with spec savers :lol:
Stuart
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Hello Paul,
Sounds like a good outcome. :nrocks: :nrocks: :nrocks:
If John sorts the controller out for you, you should be good to go.
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Could be that the board has arrived.....
I've been in Gateshead all weekend, got home to find the postie had left a card....
Need to collect summat from the PO tomorrow....needs signing for..
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motor is back on mill in excitement, wish I had noted which pulleys the belt was on before I took it off, I have a choice of 3! Need to pay more attention to this machining lark :hammer:
Fire extinguisher is ready, spare fuses, all flammable items moved, Kevlar undercrackers ironed and ready to wear
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Looks like the controller could be on way back to me, fixed!! Lets hope postie does not lose it, or break it! and the motor does not damage it when all hooked up. John has done it already, I am sooooo grateful :mmr:
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Hi Paul,
Looking forward to good news when you get it all rebuilt. Just one thing, I don't know if you have checked for any leakage to the motor case from either connection. If not then I would do so before reconnecting the controller board. Simply because we don't know what caused the power FET failure in the first place.
Ideally you would use a megger for this test. Any electrician worth his salt would have one.
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Having been in the same position myself, Paul.
I've got everything crossed for you.... :thumbup:
David D
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Looks like the controller could be on way back to me, fixed!! Lets hope postie does not lose it, or break it!
Yup I posted it this morning after a final test.... :zap: All is well...
I wrapped it then put in bubble wrap then put it in its box....
It's gone via parcels and need signing for...should receive it tomorrow... :coffee:
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I'm afraid, very afraid!, For amusement to all, will post up results :thumbup:
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Don't keep us all in suspense! :poke:
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Maybe the postie hasnt delivered?.... :coffee:
I hope there's a happy ending to this.... :beer:
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Can I take my tin foil hat off yet , I have had my ear plugs in , hang on I am 90% deaf so the bank would have to be in BSL
Good luck hope all goes wel
Stuart
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So it is now Tuesday....and no news......
I've no finger nails left....
Hope everything is ok...... :zap:
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well here it is, the news, Tonight I ventured out to the man shed, armed with the necessary tools, full of hope
asbestos gloves, cyno glue, a selection of man hammers, and something to thrash the machine with
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What a tease....... :)
My repair is sound....you won't need a hammer to beat into submission....Unless you need it for some other reason :lol:
C'mon we need an update......I'm now down to my elbows... :zap: :dremel: :beer:
:worthless:
There's more suspense in this thread than a Hitchcock movie..... :coffee:
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And? :scratch:
Awwww....... Come on! It's my bedtime! (http://freesmileyface.net/smiley/others/others-159.gif) (http://freesmileyface.net/free-others-smileys.html)
David D
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I can't stand not knowing any more, the bells, the bells, the sand, the heat, the flies! :loco:
DOES IT WORK?
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sadness abounds, and here is the proof.
yi9-g
so, at first all is well, although a lot of "pot" movement before anything happens. When the first fuse blows, the motor emitted a big spark at brushes end. I did note when running, it was like having a small misfire in an engine, it wasn't real smooth. It was noisier than before, however the belt was slack, and I don't know if it was on the correct pullies at this time.
You can see what happens after that. I have put a 60w bulb on the output of the control board, its gone back to how it was prior to Johns repair (real sorry John, I wanted it to work as much for you as for me!). With pot turned off, bulb is very bright, turn up pot, brightness stays constant, John tested this and he has a proportional brightness with the pot.
So back to square one unfortunately, and I have probably blown Johns repair, however, I can solder John, and thanks to you sending the part back, could probably change it out again.
So peeps, I don't know what is the cause, change motor, its not motor and keeps blowing board, change board, and its the motor??? I stripped motor again, cant see any sinister goings on.
I am thinking change the thingy John did, and the pot? try again, hopefully the video will give up a clue, now where is the thrashing thing, this machine needs a dammed good John Cleese style thrash :D
PS..., Just watching video back again, when first turned on, you here the motor, but see its not turning, so no real slow drive, then up to 0.34 you can here the speed isn't exactly constant. For reference, when it first went bang last year, fuse just blew, I had slowed the motor down
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Sparking from the com like that is indicative of either an adjacent short or open circuit.......there should be little or no sparking....assuming the brushes are in good nick...
So, to the controller,advancing the pot quite a way before anything happens points to the motor...(I'm not trying to exhonerate myself here... :( ) the lamp I used lit more or less straight away...albeit at reduced brightness, which is what you'd expect...
If you attempt a repair, unscrew the bolt securing the heat sink to the mosfet(an IRFP450 you can get them from Ebay at reasonable cost), remove the heat sink from the board, then cut the mosfet legs with side cutters, then remove the remains from the board gently.....don't overheat the copper pads on the board else there's a risk of it delaminating.....reassemble, test with a lamp bulb to see all is well....decide what to do about the motor...
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That motor has released its magic smoke :zap:
As John said its looks like a short , windings or comm I cannot be sure.
If it was me in your place I would repair the board as per Johns post and get a new motor .
Stuart
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Or possibly sticky brush(es).
f you live anywhere near St. Albans and could drop the motor off, I could give it a going over for you (within the limitations of the equipment I have). In the far distant past I did some design work on PM brushed motors, some with (what were then) exotic magnetic materials.
I did notice the unusual label on one of the lamps on the control box - "unnormal".
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Hi Paul,
Sorry to learn the sad news. :hammer: :hammer: :hammer:
I wonder did you do the insulation of the motor windings to case check as I suggested ? You never said.
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Metering/ Meggering to deck may not show the fault if it is an inter-winding fault.
My WM16 motor went pop about 18months ago and meggering from a brush to the casing while turning by hand showed nowt at all ... :thumbup: but ......
Stuck it on my Variac via a bridge rectifier and it was fine until some 40V r.m.s. then the arcs tracked around the commutator ... amusingly :zap: but not helpful. If I let it cool off for a bit it would run for several minutes OK below the 40V mark. New motor fixed machine, it didn't kill the KB board ( the thyristor version).
Maybe some winding had chafed in the slot and was shorting to adjacent turns ??? Hoo nose ???
Commiserations to Paul .. :(
Dave
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ok all,
just so I have not mislead you, the sparking wasn't/isn't constant, it was more a flash as the first fuse blew. Motor was stone cold, brushes are perfect.
Bluechip, thanks for input but have no idea what you are talking about, remember, I am thick!
Baron, same sorry, I thought you guys might get fed up of me! so didn't reply due to embarrassment :doh:
Pete, many thanks for very kind offer, but I am Wirral, so miles away
John, I will try to get back to what you had, can you please post an ebay link for the right fet, I had a quick look, and there seem to be different specs for that part number. Ill get a pot from arc euro also, for that price it is worth it, then if all agree its the right course of action, at least get back to a proportional bulb as John had it. If I have a spare fet, then I can try on the motor, if it blows again, change the fet again, and with a new pot it must be the motor?
I would have thought the motor would give a clue, such as smell of electrical death, burning, burnt wires etc. As the motor could have been the original fault, I have no way of going back to our "expert", he had it running for a while on 60vdc, I take it when it starts to get up to 230vdc that is when things go wrong!
Paul
Is there a very simple test I can do on the comm, such as a test light on each segment to establish anything worthwhile!
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Paul yes there is a test
It's simple when you have the required DC source it's called a volt drop test but that motor has a thick winding in relation to its size you would need to measure about 0.1 volts and a current limited 2 volt source
Stuart
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Paul
There's not much you can do as a lad in his shed if you don't have the gear. Testing motors is far from simple.
A 240VDC motor should run on 12VDC from a car battery. You might try that. It will be slow and if you put a bit of drag on the spindle with your fingers you can tell if the is/are 'dead segments' on the commutator.
Be careful, it could be quicker than you think. :lol: and be certain that you can disconnect in a hurry in case it's a short circuit .. if in doubt don't :thumbup:
If it runs OK there is a fair chance it's a goer, but my knackered motor would do that anyway. So it's an indication, nothing more.
Other than that the only sure way is substitute the motor. :(
Dave
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Paul
Please do not be offended by this.
When you had the motor apart did you mark the end bells in relation to the body ?
The ones I've seen did not have notches to locate them.
The end bell fixes the brush position with relation to the field and is critical to the correct running and has to be set to a position called the neutral point in a motor that can be reversed
Stuart
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Paul,
Cheapest I could find is here....290589749229
If and when you come to put it all back together, get hold of a 60 watt lamp and holder, wire them so that the bulb is in series with the mains in to the controller......it will act as a current limiter and will prevent ( hopefully ) you from blowing another mosfet in the event the motor is damaged.....assuming you get to the point of testing with another lamp in place of the motor.....
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When you had the motor apart did you mark the end bells in relation to the body ?
The ones I've seen did not have notches to locate them.
The end bell fixes the brush position with relation to the field and is critical to the correct running and has to be set to a position called the neutral point in a motor that can be reversed
A good thought - well done that man!
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will order now john, it must have blown again as symptoms are now the same.
Stuart, I paid no attention to that, however might be lucky. With the two studs that go from top to bottom inside the can, you can only assemble in one of two ways, so the end could be 180 degrees out. I would have thought that didn't matter? as the brushes are infact in the same place, or does it as one will be positive and one negative connection?
Looks lie I am having to buy a motor then, and cant believe only arc euro sell them at £88, what an expensive do that is!
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Hi Dave,
I ran the motor on 12v some time ago, it wasn't quite enough to spin the shaft. When I collected it from the tester guy, he had it running fine on 60vdc to prove to me the ac input had not ended the motor. Maybe now it was back on 230vdc, it was just too much. What a dilemma.
I was tempted to get my lathe out and start swopping bits over, such as motor, but I really don't want to end up with two dead machines, its just not worth the risk as I don't know the original cause.
Paul
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Stuart, I paid no attention to that, however might be lucky. With the two studs that go from top to bottom inside the can, you can only assemble in one of two ways, so the end could be 180 degrees out. I would have thought that didn't matter? as the brushes are infact in the same place, or does it as one will be positive and one negative connection?
If you assembled it with the brushes 180 degrees out the motor would run backwards because the field from the PM and the armature would be reversed relative to each other. If you look up "Fleming's Left Hand Rule" in Google / Wikipedia all will be explained (it's a way of remembering how the field and current interact to create movement using the thumb and first two fingers of the left hand).
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Pete
Ye gods it was eons ago when I was taught the Flemings rules
Paul
Yes I agree the studs we go though but the brush setting has to be accurate to one com seg
Now this will sound odd in what has been said about DC motors and AC one the big stuff 75 hp up we used a 1 kW heating element and applied the AC to the field coils with the com coils disconnected with a volt meter across the brush gear we set them for a null
As Dave has said the motors can seem to be to be ok but fail when fed with the pulsed DC from the controller we tend to test with a steady DC source when we should be testing in normal operating conditions, which is the practice that I have normally used at work , strictly against H&S as I normaly tested with the circuit live .
Along with dave I have lost a motor on a x3 mill tested fine but released magic smoke and sparked . Not worth my time to rewind it which I could so got a new one and enjoyed using it to make my models
Just my 2cents on the matter
Stuart
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Ye gods it was eons ago when I was taught the Flemings rules
Yes, about 45 years in my case.
On the whole it does look like the motor is faulty - assuming that the rest of the circuitry has been inspected for poor connections, frayed / chaffed wiring, dry joints etc. So it looks like a new one or a re-wind. Has anybody any experience of getting motors rewound and what is costs? I can't imagine it's cheaper than a new motor in this price range.
You may have seen my post on the acquisition of a virtually new Clarke mini-lathe for spares, only to find its odd and erratic behaviour wasn't down to a duff control board, but caused by a dodgy connection in the wiring, so it might be worth a last double check prior to splashing out on a new motor. If you have an emergency stop button like those on the mini-lathes, it is worth paying attention to the soundness of the spade connections to the emergency stop button and checking that the contacts don't rub on the insulating covers of the spade connectors.
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Only 45 years you young pup
Let's see it would be about 1963 so that's about 52 years ago
As to a rewind it should not be to bad if you are set up for stoving and balancing be a six hour job so not worth it hek I did not do my own not cost effective
Regards Stuart
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I agree, rewinding an armature of that size is just not cost effective.
I see two reasonable alternatives, go for a belt conversion with an induction motor or find a treadmill with a similar (physical size) motor and use the controller from that, though it should be possible to modify the existing controller by fitting larger FET's.
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thanks chaps, new fet on the way, thanks to John I know how to do that, and I got a new pot, a few quid, so worth having. Ill get the board operating as it was when it left John.
I will tonight revisit all connections just for a last look, I fancy another look in the motor (I can now disassemble in less than 5 minutes!), then looks like its bite the bullet time with the motor. Hopefully its not a new board after all this as they are now out of stock anyway! :hammer:
Fleming's Left Hand Rule
read it, so, in theory, if I have a circuit tester on opposing segments of the comm, the circuit should be sound, if not, its burnt out, and would this have caused the misfire I briefly experienced? Then if the motor was slow enough, or stopped on the dead segments, would that have been the short circuit, big flash, and fuse blowing?
Sounded a very clever statement by me, ha ha :headbang:
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Paul
In theory yes in practice no
The resistance of the winding is so low you will not be able to tell if it's ok or a short.
First you would need to know if it's wave wound or lap wound
To give an idea on the armatures I used to rewind the coil was just a u shaped loop of 1/2 inch by 1/16 inch coper tape thing of the difference between that and a short , not so easy
That's why you do the volt drop test to pick up the difference between each seg , not a definitive reading but a consistent one across the entire commutator then it's deemed to be ok.
I do think it's the pulsed DC that causes the flash overs were a steady DC will not but the motor by your comments has not been tested on DC above 60vdc it would have been good if it could have been tested on a higher voltage for that my have shown up the fault
A point to note these controllers put the full volts on the motor but for slow speed they only turn on for say 5% of the time as you advance the pot it turn on for longer until it's on full time for full speed , so the motor always sees the full volts but in spikes
Have fun but be safe bet you know more than you wanted now , but you asked for help 😄
Stuart
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In case you need it, a manual for a micro mill (which might be yours - it uses the same motor), including an exploded parts diagram is available here:
http://www.boukal-naradie.sk/soubory/36498/Manual_SX0.pdf
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well that proved nothing, other than its gone cold outdoors again, and the shaft circlip has disappeared to the other side of the county when I took it off :palm:
The comm has a circuit all the way round, no matter what segments I am on, don't know what that means! probably nothing :scratch: Im bored with this machine now, its time to finish my latest project which does not need a milling machine, where did that ball of wool go?
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I feel your pain, all through this ordeal. :coffee: :bang: :beer:
Maybe for next time one little bit of assistance:
When removing (or replacing) a circlip from anything portable, have it lying on the bench in a clear plastic bag as you operate on the patient.
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Good scheme except .... the need to capture the damn thing to put it into the bag ... :bang:
Usually ping off to join the rest of the bits around Saturn or wherever .. never to be seen again.
I used to have circlip pliers that were 'hollow ground' on the tips, thereby making it likely the clips would remain there until grabbed ... not any more it seems ... just got a new set that aren't ground ... :(
Ah Well ......
Dave
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Maybe I wasn't to clear in writing that! :)
I meant, put the motor into a clear plastic bag, set the whole on the bench, or kitchen table, or bedspread, depending on you marital status, then insert hands and removal tool into bag, and remove circlip while all are again, in the bag.
If circlip pops off it is still captured in the bag instead of migrating at high speed to the eyeball, turf, snow bank, or to the dustball behind the dresser or into the toilet, depending on the little boogerhead's whim.
Do it as suggested, and it's always......ahem, in the bag. :lol:
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ah well, circlip is last of my problems now. I fitted the new fet tonight, but, didn't realise that the screw holding the heatsink had to line up, so then had to remove the new fet and fit the spare. Whilst getting it off, I "could" have damaged the board, really don't know, because when I powered it up with a test light, all was well for a few minutes, then one leg of the fet sparked, and that was the end of that .
I possibley (likely) need a motor, and now need a board, its really not worth it, too expensive, and the board is out of stock anyway at the only place with one, arc euro trade.
I have to call it a day, and will consider selling the machine for parts/spares. Buying both parts is the only way I will be sure that its fixed, luckily the board was not fitted back inside the case when I did the test, otherwise I would not have seen the fet sparking.
I need to pack it up, and think long and hard, almost £200 to get it working again, I bet the machine isn't worth much more than that.
Many thanks to all that contributed :mmr:!!
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With a new one for £399 , I doubt you would get a ton for the bits
Sorry it's not the outcome you desired but your knowledge will have increased a tad
Stuart
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im thinking that it may still just be the board that's at fault here, it may well have been what actually failed last time and caused the sparks at the motor end.
personally Id persevere with it, but i'm stubborn and hate getting new things when Im sure they can be fixed, plus have equipment and tools to test with.
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I just called arc euro, who where very helpful, to see if they have returns, refurbs etc that might help. They have offered for a nominal cost to test both motor, and controller actually on machines, so they will be at a working environment. Then will call me to review what faults I have, and what it will all cost, then I can decide on course of action, as Bertie says, it might just be the board, and as Stuart says, no point in throwing £200 at this
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... all was well for a few minutes, then one leg of the fet sparked ...
Showing my ignorance again; would a FET actually spark if it failed? I've seen an i.c. with a crater in the top after a stupid amount of power was put through it, but am unaware of transistors sparking when they failed. I could quite imagine a spark at a dodgy solder joint though.
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yeah it was a spark that was visible even under fluorescent light, on one leg, then after turning off and back on, another leg was emitting what can best be described as a glow!
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That could have been a bad solder joint.
edit, oh well re-reading, a glow is not just a spark, nevermind.....
edit2, well re-re-reading, maybe spark from bad solder joint came first, then glow on powering up afterwards due to resulting circuit fault?
Anyway, nice of the distributor to try to help, and they will certainly figure it out....
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If you can do with a little AC motor i have one from a Clarke bench drill that got knocked off the bench and shattered the head, i removed the motor and switch and binned the rest of it. Will look at the plate to see what it is tomorrow.
Lyn.
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well the news is in from Arc Euro Trade. My motor, and control board have been tested independently on a machine under working conditions.
The board is past being salvaged. The fet I fitted is gone, the board is damaged (no doubt by me) the potentiometer shows signs of fault. On/off switch not tested alone, its not worth bothering with, when used with a perfect motor after a few minutes was getting hot!
The motor ran ok at low speed, higher speeds emitted a lot of sparks, showed signs of the misfire I reported, became very noisy, they said if used at lower speeds might be ok, but lacked any torque, so its on its last legs. Which failed first, did one component take out the other, what about the fool who stuffed ac into the motor, well that is all in the past now, so decision time.
Its £200 to replace the two parts, plus its not worth sticking with the original pot and on/off switch. new machine is £399, ok not with the belt drive, longer table I have, but brand new.
I said all along I would not spend £200, but now I am in the corner I wasn't really deep down expecting, and I have the nominal fee to pay for the tests. I could buy second hand, but if coming from an unknown source such as ebay I could be back to all this in a short space of time. Maybe they machine is an expensive luxury, I only use it occasionally, and then its just some dabbling with model planes and boats, but its real nice to have, and I have a load of tooling now!
I could raise some cash, the machine sold as spares etc should raise £100 (one on ebay now without my upgrades is at £90), I also have a couple of model boats in the attic that could sell as I will probably never finish them.
Is it worth spending £200 on a machine a few years old, or call it a day and move on!
Paul
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Maybe a quick Wanted on freecycle for an old treadmill? will have motor and controller for free if you are lucky? or a quick scourer on gumtree for something cheap to be a donor?
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If you can find a cheap / free motor somewhere, then finding a motor of about the right size, speed and power is the starting point. A cheap controller to suit will be found on ebay.
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Paul,
Pm sent....don't give up yet... :zap:
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shame the motor has gone as well as the board, was hoping it would be a simple fix for you, but at least now you know what's wrong.
definitely don't give up on it, you'll only lose money getting a newer one, and who's to say that wont take lots of work to get set up just right.
better the devil you know I think, you've got a good machine all set up, just need something to power it with. Any reasonably powerful motor with speed control should do the job. treadmills seem a good source if you can get one cheap. or even something like a washing machine motor could get it running again.
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Hi Paul
Followed this posting with great interest loads of help and good advice.
Now you are faced with how to get the best option to get back to milling again.
I have an X2 mill drill that has been radicalised so it is hard to recognize.
The treadmill motor is a good option however it can be a shoehorn job as they are all bigger than the original motor.
Anything over 110 mm diameter and the job becomes much more difficult.
This is controller I can recommend as I have in use three on various workshop machines.
The flywheel and pulley are removed and discarded and pulley fabricated to fit.
I have not had any problem running the motor in either direction that has the brushes at 90 deg to the centre line of the shaft.
http://www.surpluscenter.com/Electric-Motors/DC-Motors/Motor-Speed-Controllers/90-180-VDC-SPEED-CONTROL-W-POT-11-2269.axd.
This is basic unit that you have to wire up yourself and setup for the motor power you drive with it.
You probably have access to many more options and at more competetive prices.
Eric
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Hi Paul
Followed this posting with great interest loads of help and good advice.
Now you are faced with how to get the best option to get back to milling again.
I have an X2 mill drill that has been radicalised so it is hard to recognize.
http://www.surpluscenter.com/Electric-Motors/DC-Motors/Motor-Speed-Controllers/90-180-VDC-SPEED-CONTROL-W-POT-11-2269.axd.
This is basic unit that you have to wire up yourself and setup for the motor power you drive with it.
You probably have access to many more options and at more competetive prices.
Eric
The Minarik controller is pretty much like the KB series, although the low level circuitry is powered by an isolated supply (the onboard transformer )....
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Personally I would look to buy from a UK source where possible. If things go wrong it's easier to send things back. It's also worth considering that postage from the US is not cheap and added to import tax means that getting goods from the US is not necessarily cheaper than buying a functional equivalent in the UK.
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Hi all, firstly, many thanks for the suggestions, and support this thread has given me, its been quite a learning curve! Here is where I am!
I seriously considered the treadmill motor, even bid on one that was on fleabay local, but, then I thought I still need a controller of some sort, and would need to fabricate some sort of motor mount, and in the end, I would be cannibalising a nice machine that has sentimental value, not to mention some upgrades, I know where its been since new, I know who supplied it, so, the friend who I got the machine off was a model engineer, I had two model boats of his that had been in the attic for nearly two years, these raised £100 last week on ebay, so in a strange way, he funded the repair :clap:
I had a few long conversations with arc euro trade, who had the record of the original purchase. They tested the motor and board on a machine, and found both faulty. The motor was ok on low speeds, but once running fast, massive arcing, sparking, and the smell of death. I am considering writing to the guy who pumped AC through it and ask for a contribution, which I think is fair?, any thoughts? The fet I fitted had failed, more than likely due to me! the pot was faulty, and there was possibly damage on the circuitry. The motor had more that likely ruined the work John had done.
So, the saga was prob, board fet all along, cheap easy fix! John fixed this, but in the meantime the motor is damaged by the "expert", which then resulted in the motor taking out the repaired board, so I now have a new motor, new board, new pot, £200!! :doh:
Hopefully all is ok now. I ran the motor at various speeds for 15 mins, it was stone cold, all seemed well. Arc euro suggested that as I only use the machine now and again, wrap the motor up to insulate it, and I have now brought the controller indoors, to stay in the house until needed................... Missus wont let me bring the lathe in! so that will be the next saga... :D
Many thanks
Paul
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Sounds like an expensive but happy ending....
With regard to redress of the damaged motor, if Arc can testify that the motor was damaged due to applying AC to it, then you might have just cause....
Sorry I wasn't able to help further.. :(
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Very glad you have a working mill after all of this, rather than selling for parts and taking the loss. You can now work again, and you have your friend's mill. That's very good. :beer:
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You are back in business - good to hear. I think your chances of proving that Mr. Numpty Repairman damaged the motor are slim. No harm in asking him, but don't get dragged into an argument if he refuses, look forward and enjoy yourself with some therapeutic swarf production.
What is your first project with the mill?
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its nothing like you boys can do! I'm currently building a radio controlled Pcf (patrol craft fast) vietnam swift boat as used up the vietnam rivers by the American army. ive done the running gear so most of the milling is done. got some milling of plastic to do, then a load of brass and ally fittings to do which is more lathe than mill
paul
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I'm sure I've seen one of these in progress recently somewhere. Are you associated with a company that does large scale armour models.
I've got a 1/6 scale jeep in the offing when the benches in the workshop are redone. It is a model of the jeep that my father used in Burma in WII, it looks something like the SAS desert jeeps that we all know from the films. I've made the pintle for the 50 Cal so far, and collected lots of parts and materials, so I'm all set - just need the benches.