The circulation pump motor stops rotating momentarily during startup
Thread Content
After the Schneider soft starter originally used in our factory’s hot water circulation pump was damaged, a new Schneider soft starter was installed. When the circulation pump was started remotely from the control room, just 5 to 6 seconds after startup the motor of the circulation pump stopped rotating instantly; the soft-start current rose to 339A before it stopped increasing (under normal conditions, the soft-start current should rise to 600A before dropping to the normal operating current of 165A for the circulation pump motor). The motor made a humming sound, and the indicator light showed green (green indicating that the pump is in operation). It is normal to turn the pump shaft after the circulation pump motor stops rotating instantly; once the pump is restarted, it will operate normally. Subsequent analyses from various perspectives confirmed that there were no mechanical issues, but the reason for the sudden stop of the circulation pump motor remained unknown. We urgently need everyone’s help to analyze this.
What caused the previous soft starter to burn out?
Is it a problem with the motor? Have the motor’s bearings been replaced? Some motor bearings have wave springs – was this taken into account during maintenance?
Determine whether there is a loose connection in the contactor at the power end of the motor~~~ Phase loss occurs at the moment of startup; the contact reestablishes itself after restart~~~~~
If it starts working normally again, it means there is no problem with the pump; the issue must lie in the motor
There are issues with the soft start settings: increase the soft start voltage drop time, ensure that the upstream circuit breaker trips in such situations, raise the short-circuit current value, and extend the delay time