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Crane failure and troubleshooting (control and wiring part)

Update time : 2020-09-16 Publisher:Dotrum

1. When the knife switch of the protection box is closed, the fuse of the control circuit is burned. Fault and cause status:
Fault reason: this phase in the control loop is grounded
Elimination method: check the grounded part of the phase with a megger and eliminate it
 
2. After the controller of a certain organization is rotated, the overcurrent relay works
The cause of the failure: (1) The setting value of the overcurrent relay that protects the motor does not meet the requirements (2) A certain link of the mechanical transmission part of the mechanism is stuck and the motor is overloaded.
Remedy: (1) Adjust the setting value of the relay as follows: I setting=(2.25~2.5) rated current
 
3. After the main contactor is turned on and fastened, the fuse of the lead-in is burned out
Fault reason: the phase is grounded
Elimination method: eliminate grounding phenomenon
 
4. The motor does not rotate after the controller is closed
Reasons for the failure: (1) One phase is powered off and the motor makes a sound (2) The rotor circuit is broken (3) There is no voltage in the line (4) The contacts in the controller are not really contacted (5) The collector brush fails (6) The brake Failure, cannot be loosened
Remedy: (1) Find the damaged place, connect the wire (2) Find the damaged place, connect the wire (3) Find the damaged place, connect the wire (4) Check the controller (5) Check the controller (6) ) Overhaul the brake
 
5. The motor can only rotate in one direction after the controller is closed
The cause of the failure: (1) The controller's reverse contact is not well contacted or the control rotating mechanism is faulty (2) The power distribution line is faulty (3) The working mechanism moves to the extreme point and the limit switch is pressed (4) The limit switch A malfunction
Remedy: (1) Check and repair the controller adjustment contacts (2) Use short-circuit method to find out the fault and eliminate it (3) Only run in one direction (4) Check the limit switch and eliminate the fault
 
6. After the end limit switch is activated, the main contactor does not release
The cause of the fault: (1) An open circuit occurred in the terminal switch circuit (2) The wires connected to the controller were disordered
Remedy: (1) Overhaul and eliminate the open circuit (2) Correct wiring errors
 
7. After the controller is switched on and off, the main contactor does not release.
Reasons for the failure: (1) The positioning machinery is malfunctioning (2) The contacts are supported in the arc room
Remedy: (1) Eliminate the fault (2) Adjust the position of the contact
 
8. The controller does not move during operation
Reasons for the failure: (1) Failure of the positioning machinery (2) Burning and bonding of the contacts
Remedy: (1) Adjust the pressure (2) File to clean the contacts
 
9. The generator is not excited
Cause of failure: (1) Excitation circuit is disconnected (2) The generator turns in the opposite direction
Remedy: (1) Check the excitation circuit (2) Change the two-phase wiring of the drive circuit rotor
 
10. After the power is cut off (the control circuit is disconnected), the contactor of the protection box will not trip
The cause of the fault: (1) There is an open circuit of the ground wire in the control circuit (2) The contactor of the contactor is welded, and the main circuit continues to supply power
Remedy: (1) Check for grounding or short circuit, and troubleshoot (2) File the burnt contacts to make good contact
 
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