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Rapid Detection Method For Electrical Faults Of Bridge Cranes(一)
- Jun 13, 2018 -

1, close the power switch, power fuse fuse blown

Cause of failure: There is a ground or short circuit.

Remedy: Check the power circuit, find the ground or short circuit and eliminate it.

2, the main contactor does not suck

Cause of failure: The emergency switch is not closed, the safety position switch of the door is not closed, the controller does not return to zero position, the contactor coil is open or there is no operation power.

Remedy: Check that the emergency switch or door position switch is closed, check the controller to set it to zero, replace the contactor coil, and restore power if no power is applied.

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3, after the main contactor pulls, the overcurrent relay action, contactor release

Fault reason: The controller circuit has a grounding phenomenon.

Remedy: Disconnect the protection disk from the controller and connect it gradually. After each contact, contact the contactor. After the conductors are detected, check the ground faults.

4, operating the controller, the motor does not rotate

Cause of fault: The motor lacks phase noise and the rotor circuit is disconnected. The controller's static and dynamic contacts are not closed.

Remedy: Find and restore the three-phase power, check the rotor circuit, adjust the controller static and dynamic contacts to make good contact.

5, after the controller is closed, over-current relay action, contactor release

Cause of fault: The overcurrent relay setting value is too small and the stator circuit is grounded.

Remedy: Re-adjust the setting of the overcurrent relay and check and eliminate the earth fault with a megohmmeter.


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