6600V Wye synchronous Motor Delta Connected?

[Decroded]

Gentlemen,

I have GE 1070 HP synchronous motor that is wye wound for 6600V and FLA of 98A and PF of 0.8. It has six leads to the stator and will turn at 257 rpm when synchronized driving a high inertial load. This motor does not have part-windings.
It has been proposed to connect the motor in delta using 4160V from a generator set. Can anyone answer the following:
1) Will the motor run properly at 4160V delta connected even though the data sheet says it is wye wound?
2) If the motor will run at 4160V delta connected, will there be a reduction in torque or horsepower resulting from this configuration?

Thanks
DC

 

[winnie]

On motors of this scale, it is not possible to give a definitive answer without a detailed engineering analysis. The specific layout of winding connections, insulation systems, etc is critical.

With that said, the change that you describe is _plausible_. In general, a wye connected machine may be reconnected in delta; the voltage drops by a factor of 1/sqrt(3), and the required current increases by sqrt(3); the total power remains the same. If the appropriate voltages are used, then there is not change in the actual voltage applied to individual coils, and the performance of the motor is unchanged.

4160 is a few percent higher than the corresponding delta voltage, however this may be related to 'usage' versus 'supply' nominal voltages.

-Jon

 

[eric9822]

I would definitely talk to a GE motor engineer prior to heading down this path. They have been helpful with me in the past.