Wiring 5.5kW motor to DELTA - Help

[Smouser]

I have the same problem.

Most places just mention low or high voltage. Does not say if it is 220/400/700V.


I have two major concerns with proceeding:
1. I am not 100% sure this motor can even be wired to 230V. It seems you guys think so, but are also not 100% sure.
2. I am scared I might do something wrong and damage it (it looks to be a really nice motor, 2-200Hz operating capability with forced air cooling).

The stakes are a bit less if you play with an old sub £100 motor.

I wonder if I should go the 220V to 380V VFD route instead.

This was the first VFD I examined. Rated to 7.5kW.
Link

It comes from a relatively trusted supplier on Aliexpress.
It is also one of their newest model numbers (SU900-7R5G1).

However, after browsing a little bit more, looking at different 220 to 380V VFDs, I came across the following types of warnings or cautions in SOME listings.

and

and

The warnings/cautions suggest that the jiggery pokery going on inside the VFDs to boost the voltage to 380 takes up quite a bit of kW capacity of the VFD.
There are also some additional warnings/cautions on SOME of the listings saying that 220V to 380V VFDs are not suitable to rapidly stop a motor/connect a brake - that will be a deal breaker on a lathe.

This, in turn, led me to the VFD below.
It is rated for 15 Chinese kW , which in theory, should be good for my 5.5kW motor.
Link

The above VFD is a little heavier (3.1kg), which hopefully is a good sign that there are a bit more components/heavier-duty components inside

Options options options...........

 

[Seadog]

If it's running at 400v in "Y", then it has to be 240v(ish) in Delta configuration. That's a certainty.

 

[Guineafowl]

If it's running at 400v in "Y", then it has to be 240v(ish) in Delta configuration. That's a certainty.

Agreed. If it were mine, I would go for 230V delta and get a standard AT1 VFD to suit, with plenty of headroom in the power rating. With all the motor protection parameters set properly, you’re unlikely to damage anything. The better the VFD, the better the manual, too.

Next thing to consider would be a braking resistor, if you want a quick stop.

 

[Smouser]

I am a sucker for being convinced to take chances

Tonight, it is me and those windings.
Marking each winding end up T1, T2, T3,T4 etc.

I am going to use the control.com diagram I posted before as reference.

 

[Seadog]

I am a sucker for being convinced to take chances

Tonight, it is me and those windings.
Marking each winding end up T1, T2, T3,T4 etc.

I am going to use the control.com diagram I posted before as reference.

Just make sure that you label every wire unambiguously, and make a table of the current connections.

 

[Guineafowl]

I am a sucker for being convinced to take chances

Tonight, it is me and those windings.
Marking each winding end up T1, T2, T3,T4 etc.

I am going to use the control.com diagram I posted before as reference.

Should be fairly easy. Six windings to find.

Start with the original U wire, whose pair of wires should be 1 and 7. Decide and label (arbitrarily) which star point will be 4,5,6; the other will be 10,11,12. Then you will have windings 1-4 and 7-10. Then do V and W, and you will have all 6. Proper job.

If you do that right, then configure as per my delta diagram, which has the numbers shown on it, phasing should be correct.

 

[Smouser]

I think I have the winding leads numbered.

I started by marking all the wires which had a line (green, yellow and red) connected to them as 'S' for the start of the winding.

I then also wrote the colour of the line they were connected to on the tags.

I also marked all the original wires that were connected in STAR. Red writing for the 'far end' and blue writing for the near end.

If everything were to go wrong, I could then at least put the motor back to how it was.

From there I started making the wire numbers.

This is what I ended up with.

I appreciate it will look very confusing for somebody who have not marked it up.

I am going to double check everything and once I am happy, I can then start the long process of soldering new leads to the winding ends.

 

[Smouser]

I don't have high temperature wires that can go the windings

More accurateley, I don't have enough and I don't think the gauge are sufficient of the ones I have.


I have some 2.5mm wire that is heat resistant up to 90 degrees and I do have high temperature sleeving I can put over the wires. Not quite sure if that will be acceptable.

Alternatively, I need to order some heat resistant wire and wait...

What gauge wire would be suitable?

 

[Seadog]

Strip the pvc insulation and use the heatproof sleeve if it's up to the job.

 

[Turbo]

Would it be possible that it is a 6 pole motor that has been wired as a 3pole to give a higher speed?

 

[Guineafowl]

It’s plated as 4-pole, and that makes sense. 4 poles (per phase) means 12 poles total. So 12 windings, each split in two for the series/parallel, hence 24. 24 coils would occupy 48 slots, which is what is there.

No such thing as a 3-pole (has to be an even number), so a 2-pole? I think the only way to do that would be consequent pole, where you’d have to reverse directions to cancel half the poles. So each phase, instead of having 4 pole NSNS, would have two as N—S. Unlikely, I think.

For a modern motor like that, plated for up to 200Hz, why bother fannying with the windings when you could slap on a VFD and turn up the speed?

 

[Smouser]

I am making progress.

Tonight I have printed some heatshrink tube to mark up the wires.

I removed the masking tape and replaced it with heatshrink numbers.

I also managed to solder all 12 new wires onto the windings.

Wires and bindings wrapped with the last high temperature sleeving I had.

I also got some of that brocott coil/motor 'varnish' on the wires and bindings.

I am not sure how long that stuff takes to dry.

 

[Seadog]

That looks like an excellent job.
Not that its much help now, but lying in bed last night it occurred to me that all you needed to do was to snip the wires at the star points then, using a multi-meter, identify the two ends that corresponded to the two coils for each phase colour. Connect each pair together and then it's a simple case of connecting each of the the three wires to the next phase wire i.e. the ends of red phase to the yellow phase wire, the ends of the yellow phase to the blue phase wire, and the ends of the blue phase to the yellow phase wire.

 

[Smouser]

Thank you very much!

We are still to see if it actually works

 

[Guineafowl]

When’s the motor rewind shop opening, @Smouser ?

 

[Smouser]

When’s the motor rewind shop opening, @Smouser ?

Bawahaha.

You are the expert!

We need to see if it works first

There is still a good chance of some magic smoke!

 

[Guineafowl]

Bawahaha.

You are the expert!

We need to see if it works first

There is still a good chance of some magic smoke!

It’ll be fine - it’s been calculated on a bit of scrap paper. That’s like a guarantee.

My first attempt, many years ago, used butcher’s string and whatever old varnish I could find. Alright for a little 500W mortiser, but still, that’s a very nice job you’ve done there.

 

[Smouser]

I got the ring terminals crimped on.

The high-temperature wire sleeve frays when it is stripped.

A little bit of heat shrink sorts the issue.

I printed some labels on the label maker for the inside and outside of the terminal box.

All wired up for low voltage.

To test the motor, I used a 4kW AT1 VFD (on a 13A plug) and 1.5mm supply cables.
So all three are insufficient for the motor

The first run

Is this motor now 230V? Who knows I will just pretend it is

Thank you very much for everybody's help, especially @Seadog and @Guineafowl.

 

[Guineafowl]

I got the ring terminals crimped on.

View attachment 499417

The high-temperature wire sleeve frays when it is stripped.

A little bit of heat shrink sorts the issue.

View attachment 499418

I printed some labels on the label maker for the inside and outside of the terminal box.

View attachment 499419

View attachment 499420

All wired up for low voltage.

View attachment 499421

To test the motor, I used a 4kW AT1 VFD (on a 13A plug) and 1.5mm supply cables.
So all three are insufficient for the motor

View attachment 499425

View attachment 499426


The first run

Is this motor now 230V? Who knows I will just pretend it is

Thank you very much for everybody's help, especially @Seadog and @Guineafowl.

I was going to say, draw some wiring diagrams and leave them folded in the connection box, but oh no - fancy labels it is…

If your meter would take it, you could try measuring the phase currents. Just on my one’s 20A limit, but might be ok if you turn up slowly. Clamp meter would be better. Some of those VFDs will tell you the current as well.

 

[Smouser]

There is actually another untold part to this story.

Earlier in the week, I was not feeling too confident about this motor so I browsed eBay YET AGAIN to look for a possible replacement motor.
The Gods were smiling on me, and I found a newly listed, brand new 4kW motor for a very good price and, critically, cheap postage. Postage was only £15

Plan B arrived yesterday.

A properly wired motor! STAR and DELTA!

This motor does not have feet, so I will have to make some.
I think the shaft size is also slightly smaller than the original 5.5 kW motor, so I would have had to get a new pulley/turn a sleeve on the lathe.

Now I have two motors for one machine