markz528
Hot Rolled
- Joined
- Sep 25, 2012
- Location
- Cincinnati
This is not a machining related question, but there are a bunch of really smart folks here that might know.
Working on a chipper. Currently a 2750 hp sync motor. Has dynamic braking going into a large resistor bank. There is a separate field controller to control the braking. Works great - stops in about 10 seconds. Mechanical brakes were a reliability nightmare and took about 90 seconds to stop.
They want to replace the sync motor with (2) 1250 hp induction motors feeding a common dual input shafted gearbox with fluid couplings. They want dynamic braking on the induction motors.
I understand the concept - close the motor leads into a resistor bank and use capacitors to excite the induction motor so that it is an induction generator. Problem is that I don't know how to size the capacitors and have been unable to find anyone that has done it. By default I was thinking of sizing them as power factor correction capacitors to 0.95 pf but that is a pure guess.
Anyone ever done this, know how to size them or know someone that I can turn to?
Working on a chipper. Currently a 2750 hp sync motor. Has dynamic braking going into a large resistor bank. There is a separate field controller to control the braking. Works great - stops in about 10 seconds. Mechanical brakes were a reliability nightmare and took about 90 seconds to stop.
They want to replace the sync motor with (2) 1250 hp induction motors feeding a common dual input shafted gearbox with fluid couplings. They want dynamic braking on the induction motors.
I understand the concept - close the motor leads into a resistor bank and use capacitors to excite the induction motor so that it is an induction generator. Problem is that I don't know how to size the capacitors and have been unable to find anyone that has done it. By default I was thinking of sizing them as power factor correction capacitors to 0.95 pf but that is a pure guess.
Anyone ever done this, know how to size them or know someone that I can turn to?