That suds pump.

[DavidA]

John (Doubleboost),

In your video covering the construction of a tank for your Harrison lathe/ Chester mill you mention that it has been converted to single phase.

Was it originally a star wound three phase motor or a delta wound one.

I suppose the question is,  are you just running the original (with the aid of the capacitor) at half voltage using  the delta winding configuration ?

Dave.

[doubleboost]

[DavidA]

Thanks for the link.  I did recall you mentioned a video,  but couldn't find it.

Dave.

[Manxmodder]

Great video,John. That shows and explains all the points very clearly  .....OZ.

[hermetic]

Just to clarify the above point, motors are not "star" or "delta" wound, they are all the same, it is the way they are connected to the supply that makes the difference, hence we see John changing the connections from star to delta. There are some motors where all the coil ends are not brought into the connector block, these function in either star or delta, but cannot be changed over from one to the other.
Phil

[John Rudd]

There are some motors where all the coil ends are not brought into the connector block, these function in either star or delta, but cannot be changed over from one to the other.
Phil

If one is savvy enough, the Star point can be brought out, the ends split, the motor then rewired for Delta....

[hermetic]

Quite right John, they can, but it usually means cutting into the binding, and then seperating the ends, adding some tails,insulating and rebinding. Not really a job for the faint hearted, though as you say, it can be done.
Phil

[John Rudd]

Phil,
Trouble is we ( savvy ones like you and me ) know this sort of thing and tend to take these things in our stride whereas the Joe in the street wouldn't know any better....so it's only thru forums like this that the knowledge can be put to use....words like 'wound' tend to infer exactly that...and it is taken that the motor is a Delta or Star wound motor rather than how the windings are or can be configured.....
Hats off to John, DB for showing how to mod a coolant pump motor to run single phase .......

[Pete.]

Just to clarify the above point, motors are not "star" or "delta" wound, they are all the same, it is the way they are connected to the supply that makes the difference, hence we see John changing the connections from star to delta. There are some motors where all the coil ends are not brought into the connector block, these function in either star or delta, but cannot be changed over from one to the other.
Phil

That's true 'star wound' or 'delta wound' are terms that are commonly used. Just as you might say 'doing the hoovering', even though you might not actually be using a Hoover.

[hermetic]

Hi John, Yes I agree, doubleboosts video does a great service in showing how to reconnect a motor. but I fight a bit shy of telling anyone to dive into the binding and start soldering. the chances of damaging the insulating varnish are quite high if you havent done it before(or been trained to do it), and it might wreck an otherwise good motor which could be put to another purpose. Then there is the safety aspect. I would quite happily do it myself, or show someone how to do it, but from the safety point of view, I think it is best to find another motor!
Phil

[DavidA]

So let's approach it from a different angle.

If there are only three wires coming out from the windings to a connector block,  how do you know whether it is connected in star or delta ?

Dave

[John Rudd]

I'd say you cannot take it for granted either way.....


The motor Id plate would give you a clue, if it's 415 3phase only, then star, 230v 3phase then Delta

The dual motors I have encountered have had all six ends brought out....

[Will_D]

Ohms law should help:

Star: You will read the Rx of two windings across two connetors

Delta: You will read th Rx of one winding.

The spec pate should tell you the VA of the motor

[DavidA]

John,

... if it's 415 3phase only, then star,..

That's what I was afraid off.

I was hoping to be able to run my Emco milling attachment via an artificial phase (capacitor ) from 230 Volt single phase.
But it won't work as I can't get to the other ends of the windings.

Wil,

I'll check the plate.  But I don't think I'll be able to do it anyway.

I'm just going to have to spend the money and get a convertor.

Dave.

[Pete.]

Would it matter much if you can a 415v suds pump on 240v though? It's not like the load varies much or you have to worry about low torque.

[DavidA]

Pete,

It might be worth a try.  At least it won't cost anything as I have a few capacitors I can use.

I suppose that as long as I didn't try to chew off too much metal at once the speed wouldn't drop too much.

Dave.


Additional.

Just re read your last.  You do realise that it is the Emco milling attachment that I was hoping to
run,  not a suds pump ? This is why I was a bit worried about running it at half voltage.

[awemawson]

You just need a small 240 - 415 transformer then the capacitor mod and your pump should run fine. There are many 415-240 small transformers kicking around that have been used when a three phase machine needs a 240 single phase feed to something and remember transformer are bi-directional 

[DavidA]

Andrew,

...your pump should run fine...

It's the milling machine attachment I was considering running,  not the pum.
I used the pump at the beginning just as an example.

Re the transformer.

Maybe I could use a standard 220 to 110 site transformer in reverse. As a 220 to 415.

Only downside I can see is that I would have to use >415 Volt capacitors.

What do you think ?

Dave.

[John Rudd]

Dave,
If you are going to use a cap system to power your mill, I'd be inclined to go the safe route and buy.....https://www.machinemart.co.uk/shop/product/details/pc-20-2hp-phase-converter?da=1&TC=SRC-phase%20convertor. one of them.....much safer than trying to jury rig something with component parts of questionable origin.....   

[awemawson]

No that won't work as neither winding is 415 v rated - you need a 240 -> 415 transformer. At a push you can use a 240 v isolating transformer wired as an auto transformer so primary and secondary are in series - it will give you 480 unless there's a tapping on one of the windings that's lower but many motors are ok on that.

Remember - volts hurt - especially when they gang up on you

[DavidA]

John,

Thanks for the link.  But there had to be a snag. I downloaded the manual for it and found this warning at the top.

...It is not desirable for use with stop start operations...

Ah well,  back to the drawing board.

Andrew,

The voltage rating could be a problem.

So,  I'll go back to the Transwave rotary converter option.

Easiest way out.  Sadly,  the most expensive .

But like a dog, convertors are not just for Christmas.

Dave

[John Rudd]

Dave,
Have a look here..... http://www.phase-a-matic.com/StaticDescription.htm

They claim no issue with a lathe/mill etc.....

[hermetic]

 DavidA, drives direct do a 240v single phase to 415v 3 phase VFD , any use?
Phil

[DavidA]

John,

Looking at the details it doesn't look very promising.

Either you are stuck with obtaining only 2/3 of the single phase power,  or you need to run an auxiliary motor as often described in the many sites on line.

Phil,

Thanks for that link.

But as I want to be able to have a ring of sockets around the workshop and be able to plug in any of my three phase motors without worrying about 'is it compatible',  I've decided to spend the money and go for the Transwave rotary converter ala DoubleBoost.

Dave.

[John Rudd]

I've decided to spend the money and go for the Transwave rotary converter ala DoubleBoost.

Dave.

I hope you and your new converter have a happy relationship.....  

[awemawson]

Too late now if you've ordered your Transwave but others may like to know it is perfectly feasible to run a "415v in 415v out" inverter off domestic 240v mains by using a 240 volt to 415 volt transformer feeding two of the three 3 phase inputs. Internally these things take in their power source, rectify it to DC then chop it about to make 3 phase AC. Usually there is a 3 phase bridge rectifier at the input - well if only two phases are supplied you still get the DC out The only caviats are a/ derate it to 2/3rds power and b/ a small number of inverters monitor the phases and will report the loss of one phase but they are in the minority.

[John Rudd]

And on the back of what you say, a 240 3 phase in will work on household mains,in the same way.....

[hopefuldave]

Too late now if you've ordered your Transwave but others may like to know it is perfectly feasible to run a "415v in 415v out" inverter off domestic 240v mains by using a 240 volt to 415 volt transformer feeding two of the three 3 phase inputs. Internally these things take in their power source, rectify it to DC then chop it about to make 3 phase AC. Usually there is a 3 phase bridge rectifier at the input - well if only two phases are supplied you still get the DC out The only caviats are a/ derate it to 2/3rds power and b/ a small number of inverters monitor the phases and will report the loss of one phase but they are in the minority.

Even easier, older inverters (ABB ACS300 series, for example) have two banks of reservoir capacitors, a little rewiring to put the neutral between the banks and live to two of the rectifier's three phase inputs and it thinks it has 480v in when you feed it 240... Again, derating by about a third is in order!

[John Rudd]

Sounds like a good idea but remember the switchers are rated for a standard 240 ac in.......so they're likely to have a Vce of around 600V.....so sticking more than 340v up them may not be liked.......

[philf]

Even easier, older inverters (ABB ACS300 series, for example) have two banks of reservoir capacitors, a little rewiring to put the neutral between the banks and live to two of the rectifier's three phase inputs and it thinks it has 480v in when you feed it 240... Again, derating by about a third is in order!

Hopefuldave,

I just happen to have two ACS300 inverters sat doing nothing for the very reason that they wouldn't run from 240V! I tried them with a transformer and they worked OK but I didn't have a big enough transformer to be able to use them on anything useful.

Do you have any pictures of the necessary mods?

 

A Hopeful Phil.

[hopefuldave]

Funnily enough Phil, I think I do... I'll try to dig 'em out, but it's not that hard to work out - when you take the cover off check for a set of 4 big reservoir capacitors (if your VFD is the same as or similar to mine, they're under the main (not the upper logic) board on the lower left, it's fairly obvious which are their leads coming through to the solder side), they're arranged as two parallel pairs in series with a PCB trace where the pairs are seriesed (is that a word?), there are two fairly hefty bleed resistors which also join on the trace you're looking for, you should be able to spot where the capacitor leads come through the board - this is where you want to put the neutral lead, I put a small brass bolt and nut through the PCB (had to drill a hole!) and soldered both sides, then soldered a 1/4" blade (Lucar) connector to the sticking-up bolt to take a crimp connector. The live i brought into L1 (I think) and then jumpered to L2 to give the rectifier an easier time.

If you're not 110% with electronics, find a radio ham / hobbyist to at least advise, you'll be creating some serious voltages in there! This is a simple voltage doubler - the full mains voltage is applied to the two banks alternately so the pair of banks charge to double the RMS voltage (about 480v under full load) or maximum to double the peak voltage (getting on for 700v) under no-load conditions. Fortunately the ACS300 series (those I've seen) have a delay circuit that puts a limiting resistor in series with the supply until the caps are charged to close to their running voltage, so there shouldn't be a big surge on switch-on.

The ripple current on the caps is increased quite a bit so the reservoir caps may not last as long as intended - if you start seeing undervoltage trips at full load it may be time to replace 'em! Also, if the VFD hasn't been in service/powered for Quite Some Time it's worth wiring a 100W bulb in series with the live and allowing the caps to re-form, or even better to slowly (stages over 1/2 hour or so) raise the applied volltage, using a Variac or similar starting at e.g. 90 volts without the motor load attached.

The one I'm using at the moment is the ACS301-4P9, which is rated as a 5HP VFD so plenty for my 3HP motor, which ABBs do you have?

[awemawson]

Dave any chance of a simple before and after sketch of that bit of the circuit diagram?

I assume it's forming a single stage Cockroft Walton doubler ?

[philf]

Hi Dave,

This is a photo of the main board in one of mine:



I have an ACS 301-4PI-3 and an ACS 311-4PI-3.

I'm reasonable with electronics (I wouldn't rate myself at 110%) but can follow circuit diagrams.

Neither have been powered up for years. I have a big variac so will power them up slowly as you suggest but I'll wait until after I've drilled any holes and done any soldering. (I've been "stung" by a capacitor before and don't want to do it again. It was in a compact camera I was looking at for a colleague and I managed to short out the flash cap with my finger. I flung the camera across the workshop and ended up with two deep holes burnt into my finger.)

Cheers.

Phil.

[John Stevenson]

Been asked to pass this message on from Ian Holdsworth AKA 'Circlip@

Sorry it's a bit convoluted but can you get a message to David D on MM forum posting of "That suds pump" to make sure that he actually has got a three phase motor on his EMCO milling head! Trouble is, although the lathe may be three phase the Head may not be, Emco drawing is a bit obscure, I often wondered if they used the same motor for both variants but just added a start Cap. for the single phase. Problem is, for both types the wiring digriam shows a STAR connection motor. Other problem is, if he puts 415 across it and it is single , the bang means a rewind as gen motors are like hens teeth and the motor is part of the construction.

[DavidA]

John,

I think he means me , David A.

Pass on my thanks to Ian in case he doesn't see this.

I agree the wiring details for the Emco attachment are a bit obscure in the Denford manual.

I'll re check everything but I'm fairly sure the plate says 415 volt.

It is connected to the lathe via a dedicated socket on the cabinet. And as the lathe is 415 Volt  3 phase I suspect that the attachment would be the same.

Dave.

[DavidA]

..I'll re check everything but I'm fairly sure the plate says 415 volt...

On checking I find that there is no plate on the unit.  So I must have been thinking about a different machine.

There appears to have been a variety of different motors fitted to the various versions.

So I'll settle for using the original connection to the Lathe..

I can confirm that it does indeed weight around 43 Kilo (as stated in the handbook). Hence the need for a block and tackle to remove it.

Dave.

[hopefuldave]

Phil, that looks very similar to what's in mine! At the top of the pic the four large ceramic resistors are the bleeds across the reservoir caps, you should just about see those below that board. You can probably buzz out to find the track which all four bleed resistors connect to and verify that it connects dead-short to all four reservoir capacitors - this is where your neutral wants to go (I managed to do it, just, without unsoldering the caps), I think I used a 6BA x 1/2" cheesehead through the board and brass nut, cleaned and polished before I started, proper tin-lead solder, of course! Onto the spare 1/4" or so of thread sticking up (on the side visible in your pic) I crimped then soldered  a male blade/Lucas (tinned brass) to take the roving Neutral. That's about all it needs to fool it into thinking it's being fed 415+ volts :-)
It does, of course, invalidate all warranties,  approvals and certifications, probably responsible for climate change, economic collapse and the English cricket team's appalling performance in the Test series too!

[philf]

Thanks Dave,

I'll have a go when I get a spare hour or so. I'll let you know how I get on.

Cheers

Phil.

[philf]

It does, of course, invalidate all warranties,  approvals and certifications, probably responsible for climate change, economic collapse and the English cricket team's appalling performance in the Test series too!

Dave,

So far so good. There were 4 pads with through holes on the top of the board available so I used them and ran 4 silicone insulated wires to the neutral.

Much to my surprise the display switched on and the fan started running at only 120v input but at 190v a relay pulled in so I guess it may have worked at that.

I smelt something like a capacitor frying so switched off. It was actually my variac which hasn't been powered up for years - must need a clean.

I'll try to connect a motor up tomorrow night. If it works OK it will go on my Fobco 7/8 bench drill.

I can't get my head round how connecting the live to 2 of the inputs helps.

You misjudged the England cricket team - thankfully!

Cheers

Phil.

[hopefuldave]

So far so good indeed! And the fastest Century on record, I sorely underestimated them :S

Using two of the Live inputs is just to give the rectifier an easier time - the current will (approximately, assuming good matching of the diodes in it) share the mains current.

Glad it seems to work, have you got the programming manual for the ACS300? I have a .pdf copy I can email if you need it...

Cheers,
Dave H. (the other one)

[philf]

So far so good indeed! And the fastest Century on record, I sorely underestimated them :S

Using two of the Live inputs is just to give the rectifier an easier time - the current will (approximately, assuming good matching of the diodes in it) share the mains current.

Glad it seems to work, have you got the programming manual for the ACS300? I have a .pdf copy I can email if you need it...

Cheers,
Dave H. (the other one)

Hi again Dave,

I've just tried the inverter (without Variac) on a 1/2 hp motor wired star. It worked perfectly!

Next job is to rewire the drill motor to star and try it on that. It's currently driven by a 3 phase input 220v Panasonic inverter (which came out of a Japanese piece of equipment) but I couldn't find a manual for it and I can't suss the parameters. I can only run it on one pair of pulleys.

I do have a PDF of the ACS300 manual thanks.

The minimum current setting on the ACS300 is 3.1a which is higher than I need but the motor will only take as much current as it needs.

Many thanks.

Cheers

Phil.