Motor starting resistor failure

[alhafeedh]

thread237-41223
Compressor motor 11.5MW, 240 bar with starting resistor 3 ohms fail (overheat)2 time after vendor RCA replaced with 1 ohm but it fail twice. we do not know reason why? is it because of rotor damper cracked or process problem?

 

[Skogsgurra]

My impression is that the motors (are we still talking about two motors sharing the load?) did share load quite well as long as you had the three ohm resistors in the circuit.

When they were replaced with one ohm resistors, the load sharing gets worse and one of the motors will take most of the load.

The motor with the highest load then probably fried its resistors and the other motor then either: 1. had to take over the whole load or: 2. the system shut down.

If the other motor took over the whole load, it would probably trip on overload. If it didn't, the second set of resistors would also fry.



Gunnar Englund

http://www.gke.org

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