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How long must the signal be applied to the shunt trip on a Masterpact NW breaker?

FA252967

23 January 2021

Issue:
How long must the signal be applied to the shunt trip and shunt close on a Masterpact NW breaker to ensure proper operation?

Product Line:
Circuit Breakers

Environment:
Masterpact NW

Resolution:
The breaker requires a shunt trip energization time of 200 ms to ensure that the breaker trip mechanism has completed its cycle and has returned to its starting point.  A shorter signal will open or close the breaker, but has the risk of causing the mechanism to hang up and not close with the next close signal.  It would close with a second signal however.
To prevent operating problems, do not pass the signal through an aux. contact (which will open in less than 50 ms).  If a PLC is used, ensure the signal duration is 200 ms or more.