Individual cases during lightning flicker
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This post was last edited by *aojiaoya0546 on 2016-8-4 22:13. All the pumps stopped during the power surge, but one pump did not stop – why is that? ? ?
①It has self-starting capability; the load is low, so the switch does not trip. It is a normally closed switch
Ahaha, this sea friend hasn’t provided detailed information about the fault symptoms! This situation is quite complex, but it can still be analyzed simply! For pumps powered by high-voltage motors, the reason why the motor does not trip is mainly that the motor’s low-voltage protection is not activated ； In the case of low-voltage motors, the reasons are more complex. In addition to the reasons mentioned on the second floor, it is very likely that the release voltage of the contactor’s coil is too high (this often occurs during power system switching tests), which results in the motor not reaching the required release level during voltage fluctuations ； It is also possible that the motor cable runs are relatively long, and the distributed capacitance of the control cables causes the residual charge in the control circuit to fail to be discharged (this phenomenon is similar to the situation where it is not possible to shut down the equipment on site) ； There are other reasons as well; it mainly depends on your organization’s power distribution method, the source of the control power, etc.