Low Voltage Column Mounted Circuit Breaker Setting Sequence Number Fault Phenomenon Possible Cause Treatment Method

When choosing Lv Pole Mounted Circuit Breakers, one is the rated current and the other is the limit breaking current.
The rated current of the circuit breaker should not be less than the maximum rated current that flows through the circuit for a long time when the load is operating normally.
The limit breaking current mainly considers that when a short circuit occurs on the load side, there will be a large short-circuit current, which seriously threatens the normal operation of the electrical equipment. If a short circuit occurs, the circuit breaker must be operated to interrupt the short-circuit current.
No. Fault phenomenon Possible cause Treatment method
1 The contacts of the manual or electric operated automatic switch cannot be closed
① The secondary circuit is disconnected ① Check the fuse, button, and transfer switch

② There is no voltage on the undervoltage release ② Voltage should be added, and it should be repaired when the circuit is open

③ The energy storage spring is deformed ③ It should be replaced

④ The reaction spring force is too large ④ Should be adjusted

⑤ The electric operation voltage is insufficient ⑤ Check the operating power supply

⑥ The electromagnetic pull rod stroke is insufficient ⑥ Should be adjusted

⑦ The motor operation positioning switch fails ⑦ Should be repositioned
⑧ The mechanism cannot be reset ⑧ Should be buckled again
2 A phase contact cannot be closed
① A connecting rod is broken ① Replace the connecting rod

② The angle between the foldable connecting rods of the current limiting switch mechanism is unreasonable ② Re-adjust
3 The shunt release cannot disconnect the switch
① The shunt coil is short-circuited ① Should be replaced
② Power supply The voltage is too low ② The voltage should be increased or the power supply should be changed

③ The screws are loose ③ They should be tightened
4 The circuit breaker cannot trip due to loss of pressure
① The reaction spring force becomes smaller ① It should be adjusted or replaced

② The mechanism is stuck ② It should be repaired to eliminate the cause of the jam

5 The instantaneous setting current value of the overcurrent releaser when the motor starts and the switch trips is too small. The setting value should be readjusted to increase the setting current appropriately
6 The noise of the circuit breaker is loud
① The reaction spring force is too large ① Readjust

② The end face of the core is not clean ② Clean the end face

③ The short-circuit ring is open ③ It should be replaced or repaired