150 HP; 220Vac; 3ph motor needs to rewind on 575Vac; 3ph??

[ziko]

Hi,
If I rewind a motor 150HP, 220Vac, 3ph on 575Vac, 3ph,
how does it affect all the motor characteristics??
- Power
- Heat
- FLC
- Efficiency
Regards,
Ziko.

 

[jbartos]

Power: Is supposed to stay since it is determined by mechanical/physical design of the motor. If it is exceeded, certain parts may collapse or will not last, e.g. shaft couplings, key, etc.
Heat: Heat will somewhat be reduced since Heatdissipation = R x I**2
and current will be smaller at 575VAC.
However, there are some Watt power loss increases related to Eddy Current Effect losses (~ Voltage**2) and hysteresis losses (~ Voltage), which are quadratically and linearly directly proportional to the 575VAC voltage, respectively (accross the parallel branch in the motor equivalent circuit). These loss increases are noticeably smaller, than the Heatdisspation above at the motor rated shaft power, since the parallel branch current is much smaller but about constant, i.e. independent of the motor shaft load.
Full Load Amps/Current (FLA/FLC): Will be lower, approximately = (220/575) x FLC
Efficiency: Will be lower than 575VAC design by the manufacturer, since the motor will have bigger dimensions; however, the efficiency will increase with respect to 220VAC since the Heatdissipation or Losses will be smaller. [sig][/sig]