Thread: Which way to connect a 3 phase motor?

I have an old 5hp 3 phase motor and have access to all points of the windings. My question is which way to wire it star or delta?

The motor is rated 400/440V but it doesn't mention star or delta on the nameplate ... but it does mention the current as being 7 Amps MESH (I think it was 7). I think the "MESH" stamped on the nameplate answers the question, but I'm unable to determine what it means.

Any help appreciated.

BTW I have it currently running in star config and it is running (but under no load).

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Hi Vernon,

Depends on your mains supply, if you've got 415V mains, then wire it as star.. if you are running on a 240V VFD then wire it as delta, but you'll need more than 15A under full load.

Ray

PS.. MESH doesn't ring any bells... got a picture of the nameplate?

Two Voltages on the name plate usually means that its is designed to run with ∆ at the lower and with Y at the higher but usually there is a bigger V difference that that shown
The will most probably run either way but it won't necessarily be as efficient.
[EDIT] usually the voltage ranges are much bigger that that shown. I think in your case thats just the nominal V range it should be under.
And yes MESH is an alternate term for ∆.
You can't hurt it running as Y as it draw less current than in ∆.

Hi,
Mesh is delta, I think it is intended for star delta starting and running in delta at the stated voltage.
Regards

Yes, MESH is just another term for Delta, like wye is another term for star.

Being a 415V delta connected motor, means you won't be able to get the full 5hp, ( unless of course you have 415V mains ) connecting it as 240V delta will give you about 2.5 hp give or take.

Ray

Thanks guys.
Sorry I don't have a pic of the nameplate.
Just to give you a bit of background ... this motor is being used to turn my existing static phase converter into a rotary phase converter. Now my SPC/RPC runs off 480V (no step down transformer used).

I had a sneaking suspicion that it was it should have been delta connected ... I'll try and hook it that way tonight.

Took me a little while to get around to it, but today I finally got the motor connected in delta ... and it wouldn't start.

Kind of expected that might happen.

I added an extra capacitor between the real phase and the generated phase and it started no problem.