I have a three phase motor that has a range of 575 Vac to 635 Vac. Is the following correct?

Under a no-load condition, the motor amps will increase with increasing voltage.

Under a full-load condition, the motor amps will decrease with increasing voltage.

Thanks,

Ron

 

NO, motor current increases with load, so more load = more current.

 

Yes, in general the no-load motor current will increase with voltage due to the magnetizing current, and the (constant) full-load motor current will decrease (assuming the voltage does not go above the rated voltage) since the motor input power remains essentially constant.

 

I'll second the yes, within context.

Decreasing slip, decreases current. At load, slip can be decreased by increasing voltage. This % slip approaches that of no load. Beyond that however, an increase in voltage increases current.

 

Yes, in general the no-load motor current will increase with voltage due to the magnetizing current, and the (constant) full-load motor current will decrease (assuming the voltage does not go above the rated voltage) since the motor input power remains essentially constant.

I'll third. This is my understanding as well.

 

NO, motor current increases with load, so more load = more current.

The key to the question is that each question is asking about what happens as the voltage is changed while the load, for that question, is kept constant.