500 HP, 440V motor

[unclebob]

What happens if you try to use a 500 hp motor, rated at 440 V , with a 6-pulse drive, rated at 600 A?

 

[waross]

Rewind the motors to VFD duty 550 V with lower current handling and get rid of transformer, which is one more component to maintain and one more source of failure. Or use the transformer for other non-motor loads.

All it takes is money.
New 600 Volt switchgear and motor starter.
New 600 Volt VFD.
New motor circuit conductors.
Motor rewind.
Space considerations for the new equipment.
The transformer is used for other motor loads.
It may be a lot cheaper to identify and remedy the present issue.

 

[unclebob]

As the project manager couldn't find anything wrong with the motor or the distribution system, he decided to replace the VFD. His company has several across the country, so they'll try another one.

 

[waross]

Did you check the voltage supplied to the internal control transformer?
A problem there, including transient voltage spikes from the other drives would impact the control board.