Home › Electrical Engineering Forum › General Discussion › how to start the 220KW ac induction motor?answers please…….. › Re: how to start the 220KW ac induction motor?answers please……..
Dear Rafi ;
I understand your situation, and accordingly to your application, I want to draw your attention to the following :
1 – If the motor consumes at full load around ” 500A ” it's certainly ” Over-Loaded “, because his nominal current should be around ” 375A ” if ” Cos φ = 0.85 “
2 – If the motor on no load consumes around ” 200A ” that means there's a load but not full, because this kind of motor should consume without any load around ” 8-10% ” of his nominal current.
3 – For this kind of application, you should use ” ATV71HC25N4 “, but be attention of the VSD Thermal Protection that will trip if it's adjusted exactly at the motor's nominal current.
4 – If the motor runs idle ( with the minimum load ) on the same nominal speed ( nominal rpm ), by using a VSD the benefit will be moderate, but if you have the possibility to reduce the speed when it runs idle you will have more benefit.