Electric Motor - 40hp / 4 pole / 3 phase

Something it wrong with your math or your typing.

40HP and you think 35A is too high?

40HP @ 460V should be around 52A

40HP @ 575V should be around 41A

Are you at 1000V or something?

The voltage is 420;

He said NO LOAD current ! (it is high!)

40 HP is rated load. No load current should be less than full load. If you are in to rewinding motors I expect that you CAN rewind it again using half size smaller wire an two more turns turns!!

Why doesn't he stick to the original wire size that came with the motor in the 1st place? Obviously, he must be repairing the winding after a damage!?

Changing the wire size will affect the performance of the motor to differ from the original rating: Unless he wants to change the Motor's rating...

CAN is not the same as SHOULD. I answered the question AND you are correct.

What is your winding configuration and voltages applied? Are you using series and parallel configuration? or what?

You cannot use 420V in delta from star if you have only 3 windings.

Why not!

If the ends of the 3 phase windings are brought out, you will have 6 ends and 3 windings (Schematic), which will allow Star Delta.

Why not!

Because 420V star if conected as 420V delta will burnout the wndings, unless he has split phases wich can be configured in series or parallel, which was why I asked the question.

Check that you have rewound it correctly with the same wire size and same number of turns that were there originally. Also, the direction of the winding(coiling directions) since this is a 4 poles, each phase has 4 coils wound alternatively (direction of coiling changes...), therefore, you have 12 coils.

If you make any mistake in the direction of the coils, you will have anomalies in the current (performance) of the motor. Anomalies are not only due to the size of wires etc.

I presume that you have some experience in rewinding electric motors, therefore you should know most of the above, unless this is the 1st time.

Thank you for the response. Actually i rewound the same way as it was but the motor had been reewound previously by someone else. That is why i think the windings were not right. It is 12sets 2 coils per slot, group of 4 coils, 48slots.

Thanks v much, i will post the details soon. The span is 1-11 group of 4.