we have a reliance motor 450 HP, 380V, 60 HZ, 602Amp, so it is run a horizontal pump to inject a water in oil wells.

So we used an VSD (518 KVA) to run this motor through 400 V, 50 HZ gen. set and after a few sec from start the VSD recorded 900 AMP and Shutdown with over load trip signal. we disconnected the coupling and try to run the motor at no-load with the same result.

So if any one help in this issue why the large current driven? and take into mind the shaft run smooth and have no sound.

 

Moh.Saleh...

how many seconds is a "few"?

An uncoupled motor of the size you cited should take no-longer than 1 second to reach rated-rpm, at 100% voltage, regardless of whether it is a 2 or 4-pole machine!

Regards,
Phil Corso