Abnormal startup of the new pump
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This post was last edited by Hardworking Operator on 2019-8-10 at 13:37. During the testing of the new pump, why does the motor emit a humming sound when it starts up, and only then does it begin to rotate the bearings, rather than causing the entire water pump to start rotating at once? The 18.5KW motor will start rotating as well after approximately 3-4 seconds
What’s the situation with turning the shaft before startup? This doesn’t seem to be a pump issue; it’s more likely a motor problem
The turning gear is functioning properly, and the coupling is operating normally. It was started three times in total, and it was the same each time. The small pump starts spinning immediately once it’s turned on, while the 18.5KW large water pump takes about 3-4 seconds to start up after being powered on. I’m not sure what’s going on; please give some guidance.
The turning gear is working properly; it is recommended to check the motor to see if there are any loose connections in the wiring, and to test the motor separately
Okay, thank you. It was tested with temporary power on site; let’s check again.
This post was last edited by CHANGBAISHI on 2019-8-10 at 15:27. Ask the electrician whether it is an inverter-driven motor; according to the standard procedure, to operate the centrifugal pump at its minimum load, the outlet valve must be fully closed. There is a high possibility of an electrical issue. Check the current; problems can also be identified after the motor starts running.
Does the motor have overload protection? If there is no problem with the pump, it is likely that the motor has a missing phase; it is recommended to consult an electrical technician to check the motor and the power supply condition
It takes 3 to 4 seconds for the motor to reach its rated speed, with a humming sound; this is how the soft starter starts the motor, and there is a 3 to 4 second acceleration period aimed at protecting the motor from being damaged during startup. A soft starter, connected between the power supply and the motor to be controlled, is used to regulate the conduction angle of its internal thyristors, allowing the voltage applied to the motor to increase gradually from zero according to a predetermined functional relationship, until startup is complete and the full voltage is applied to the motor. This is what is known as soft starting. During this process, the starting torque of the motor increases gradually, as does its speed