manuel bonilla
Member
- Location
- San Jose, Costa Rica
I am doing the inspection of an electrical fire pump system that I had specified. I asked for a part winding start to reduce start current because the motor is a 40HP, 120/208V motor.
When I did the starting test the motor would not rotate during the first part of the starting sequence an would then rotate once the second contactor was connected.
In my opinion, when I connect the second contactor I am seeing a current inrush similar to that of an accross the line starter (locked rotor of the first coil + locked rotor of the second one). Therefore I am not seeing any inrush current reduction.
The manufacturer says it is normal for a part winding not to rotate on the first coil (actually Nema MG-1 does accept this, but is this logical on a low inertia, low friction load like a centrifugal pump?)
Should I accept this system?
Reegards,
Manuel Bonilla
San Jose, Costa Rica
When I did the starting test the motor would not rotate during the first part of the starting sequence an would then rotate once the second contactor was connected.
In my opinion, when I connect the second contactor I am seeing a current inrush similar to that of an accross the line starter (locked rotor of the first coil + locked rotor of the second one). Therefore I am not seeing any inrush current reduction.
The manufacturer says it is normal for a part winding not to rotate on the first coil (actually Nema MG-1 does accept this, but is this logical on a low inertia, low friction load like a centrifugal pump?)
Should I accept this system?
Reegards,
Manuel Bonilla
San Jose, Costa Rica