Motor wiring question

[Maker]

I've got a 3 phase 415 volt motor that only has three connections so it can't be converted to 230 V by swapping linkages over. I've opened it up and found all 13 soldered connections in the windings:

Three connections are red-red wires, three are black-black, three are yellow-yellow, three are red/black/yellow-mains supply and 1 is red-black-yellow.

It's a 4 pole motor so I assume the connections with two wires are where two poles are connected in series and the one with three is the centre of the wye diagram below (Neutral?)?

Am I right in thinking that in order to wire it as delta for 230 volts I need to desolder the red-black-yellow connection and solder the red from this to the black mains connection, the black from the centre to the yellow mains connection and the yellow from the centre to the red mains connection and bring these three new connections out to the mains plate in the motor?

If none of that made sense I'll draw a diagram of what I mean.

 

[BrokenBiker]

have you seen doubleboosts vid on his coolant pump motor conversion from 3 phase to single phase? that might help

 

[Maker]

I think I have seen it, but his motor had 6 connections where the ends of each winding are brought out so the change voltages he only had to swap some linkages over.

 

[Sidewinder]

Yes and no, but...

You need to find the start of phase 1.
You need to find the start of phase 2.
You need to find the start of phase 3.
You then need to find the finishes of each.
Yes you may have windings in series, or they may be in parallel.
You connect the start of 1 to the finish of 3
The start of 2 to the finish of1
The start of 3 to the finish of 2.

There is no such concept of neutral in a current consuming device which is balanced 3ph.
Neutral is a supply side concept.

You still can't run the motor on 1ph L & N 230V even if you convert it, you will need 3 phases split by 120 degrees.
Where will you generate the rotating electrical field when you only have one sine wave.

If your windings are in series, then the impedance of the "prior" winding will affect the current and voltage waveforms at the "following" winding, so, this will possibly not convert well, from star to delta, (it's star, not wye, the Americans use the term Y!)
In the IEC world its star, in the backward NEC world its wye.

It may well work, it may well not work.
Without understanding the mechanics of the stator I can't tell from here.

 

[waddycall]

I did this on my bench grinder. You disconnect the star point and connect new leaders to the ends of the windings you've disconnected. You can then connect the windings in delta rather than star in the terminal box. I insulated my leader connections with PTFE and heat shrink before closing the motor up.
I'm no expert. I was guided by the electric motors in the home workshop book. I mounted a couple of capacitors in the base of my grinder to act as a static phase converter. It's been working a treat for two years now. I always have it connected to an RCD though!

 

[Maker]

Yes and no, but...

You need to find the start of phase 1.
You need to find the start of phase 2.
You need to find the start of phase 3.
You then need to find the finishes of each.
Yes you may have windings in series, or they may be in parallel.
You connect the start of 1 to the finish of 3
The start of 2 to the finish of1
The start of 3 to the finish of 2.

There is no such concept of neutral in a current consuming device which is balanced 3ph.
Neutral is a supply side concept.

You still can't run the motor on 1ph L & N 230V even if you convert it, you will need 3 phases split by 120 degrees.
Where will you generate the rotating electrical field when you only have one sine wave.

If your windings are in series, then the impedance of the "prior" winding will affect the current and voltage waveforms at the "following" winding, so, this will possibly not convert well, from star to delta, (it's star, not wye, the Americans use the term Y!)
In the IEC world its star, in the backward NEC world its wye.

It may well work, it may well not work.
Without understanding the mechanics of the stator I can't tell from here.

Thanks for that.
So is the start of each phase is where the original mains supply connected and the end of each phase is the point where the red, black and yellow wires all meet? (The point I incorrectly referred to a neutral?)

I know it will still be three phase, but I've got an inverter so it's not a problem.

How can I tell if the windings are series or parallel?

 

[Sidewinder]

The starts & finishes may be at either end of the winding, but, they must be consistent, else the motor would not have run in star.
Series is the windings wired in series, one after the other, parallel is the windings connected across the same wiring.
You would need to do some tests.
Series windings,each individual lower than the sum.
Parallel, each individual higher than the sum.

 

[Maker]

When you say higher or lower than the sum, are you talking about resistance?

 

[Sidewinder]

Yes

 

[Pete.]

Have you tried the most basic thing which is simply connecting a capacitor across live and the spare winding? A star wound motor will still turn on 240v especially if it's a low load like a coolant pump. I pulled a motor out of a automatic barrier, it was 3 phase 415v running on 240 with a capacitor and it only had 3 wires, I hooked it up to my vfd and it ran fine if a bit noisy.

You might be pleasantly surprised.

 

[waddycall]

Can you not just disconnect the star point where the three windings meet, add some new leaders to the disconnected ends and then use a a meter to identify each winding and reconnect in delta?

 

[Maker]

Can you not just disconnect the star point where the three windings meet, add some new leaders to the disconnected ends and then use a a meter to identify each winding and reconnect in delta?

That's what I had thought, but Sidewinder is implying otherwise.

The starts & finishes may be at either end of the winding, but, they must be consistent, else the motor would not have run in star.
Series is the windings wired in series, one after the other, parallel is the windings connected across the same wiring.
You would need to do some tests.
Series windings,each individual lower than the sum.
Parallel, each individual higher than the sum.

I measured the resistance of the windings, each one was about 1.5 ~ 1.7Ω and all 4 together were about 6.5Ω, so it is series wound.

 

[Sidewinder]

That's what I had thought, but Sidewinder is implying otherwise.


I measured the resistance of the windings, each one was about 1.5 ~ 1.7Ω and all 4 together were about 6.5Ω, so it is series wound.

Not quite, just suggesting that you get it right,coz, it could release the smoke if you get it wrong, and then you're stuffed! ;(

Now, you said that you have multiple windings per phase, yes?
It is these that you need to check if they are series, or parallel, I could not tell you what they should be, or are, not the 3 sets of phase windings.
So you need to measure each phase, then split these at their joints to check.
It may not matter, I just hope that whichever way you go it works, else you'll be looking for another motor.
I would rather that you check and it doesn't damage the motor for you.

Yes, hopefully, you should be able to simply split the star, and then change it to delta, but, you need to make sure that you don't get the starts & ends mixed up.

I'm not trying to stop you, just to make you double check, so, 1st you don't hurt yourself, and 2nd, it don't break!

 

[Maker]

Now, you said that you have multiple windings per phase, yes?
It is these that you need to check if they are series, or parallel, I could not tell you what they should be, or are, not the 3 sets of phase windings.
So you need to measure each phase, then split these at their joints to check.

Yes, there's 4 windings per phase, I measured the resistance between the star point and the mains feed of one phase (~6.5Ω), then measured between each of the connections between the windings in that phase (~1.5Ω each).
Tomorrow I'll split the star point and resolder the starts to the ends as you described.
Thanks.

 

[Sidewinder]

Yes, there's 4 windings per phase, I measured the resistance between the star point and the mains feed of one phase (~6.5Ω), then measured between each of the connections between the windings in that phase (~1.5Ω each).
Tomorrow I'll split the star point and resolder the starts to the ends as you described.
Thanks.

Just don't blame me if it goes wrong!
I'm not there remember...

 

[waddycall]

Why not solder some leaders on and run it all out to a terminal block so you can experiment with different arrangements?

 

[Maker]

Why not solder some leaders on and run it all out to a terminal block so you can experiment with different arrangements?

Because the way I'm doing it is the only way that'll do anything useful, other ways of wiring will probably let the smoke out or make a horrible droning noise and I'm not comfortable experimenting with three phase mains voltages, especially if a cock up could result in a broken motor or worse yet a broken inverter.

 

[waddycall]

Because the way I'm doing it is the only way that'll do anything useful, other ways of wiring will probably let the smoke out or make a horrible droning noise and I'm not comfortable experimenting with three phase mains voltages, especially if a cock up could result in a broken motor or worse yet a broken inverter.

Connect it up, switch it on if after a second or two it's not working turn it off and try again. Unlikely to go up in smoke in a couple of seconds. If you solder it all together internally and get it wrong it'll be a lot harder to sort out.
I've converted my drill and bench grinder this way. Drill worked straight off. I dropped a clanger with the grinder and had to rearrange a couple of wires. If it had been soldered together inside I think I would have probably given up!

Good luck with it. It's very satisfying getting something that shouldn't work to work!

 

[Wedg1e]

If you do start snipping and soldering, don't forget to strip the enamel from the copper or your solder won't do much

 

[Jameswood]

Hi guys, post revival, I've picked up a washing machine motor, but I have absolutely no clue how to wire it up to a 13 amp plug. Tripped the RCD 3 times already, so i was wondering if you could help me out. Thanks. p.s the back and white wires are the brushes. What do I connect where?