How to solve abnormal motor start

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Release time:

2021-10-28

When an HBT60A concrete pump stops and starts again after pumping, the motor cannot start. It sounds as if the power is insufficient. At the same time, the AC relay of the star-connected motor power supply "snaps" and snaps. At first, it is suspected that the power supply voltage is insufficient or the phase is small. After inspection, the three-phase voltages are very stable. When we replace the AC relay, the relay no longer beats, but the starting sound of the motor is still abnormal. After the motor power supply is converted into triangular connection, the starting sound of the motor returns to normal, but the pressure in the main oil circuit of the machine remains high, while the pumping operation is normal. After stopping pumping, the pressure in the main oil circuit remains high, indicating that the main pump is not unloaded. It is speculated that the abnormal start of the motor may be due to the start of the motor with load, and the fault is not on the electrical appliance.

When the motor starts normally, the main oil circuit is impossible to have pressure. If the hydraulic oil is not clean, the main oil circuit electro-hydraulic reversing valve is blocked, which will lead to the failure of the oil circuit, causing the motor to start with load.

Brief Analysis of General Working Principle of Electric Hoist

The motor does not rotate after starting, and heavy objects cannot be lifted.