High and low current interlock of the motor
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Some pump motors are equipped with high and low current interlocks to shut down the pump, mainly due to requirements in the process and equipment. Does low-current interlock have any practical significance as a protection for motors?
Motor protection generally does not include low-current protection; depending on the equipment driven by the motor as part of the process interlocks, there is a shutdown interlock when the load is low.
Of course, there are such cases; for example, process requirements dictate that a load must be present and the system cannot operate without material, which is when its importance becomes evident.
No-load operation represents undercurrent for motors; overcurrent and undercurrent are indeed necessary for protecting pump motors.
A low current may cause the pump to be emptied, which can damage the pump; therefore, it is recommended to have it in place. (Personal opinion)
For self-lubricating pumps such as those using magnetic force, under-current protection is essential; otherwise, the pump will be damaged within 30 seconds of running idle. We have a magnetic pump that, since it was purged with nitrogen before operation, had its shaft sleeve break during a short test run (just a few seconds). This post was last edited by pansysguo on 2009-4-1 21:46.]