circuit breaker overhaul

Update date:2018-06-22 Source:MAXGE

circuit breaker overhaul

(1) Ensure that there is a safety distance between the external arc extinguishing chamber of the low-voltage air circuit breaker and the conductive parts and the grounding parts of the adjacent electrical appliances, and eliminate the arc shields of the leakage circuit breaker. The low-voltage air circuit breakers can only be put into operation after strictly following the requirements of the “Low-voltage Automatic Air Switch Inspection Regulations” to install the arc-separation plates. Otherwise, the arc is easily generated when the circuit is cut off, causing a short circuit between the phases.


(2) It is necessary to check periodically whether the signal indication of the low-voltage air circuit breaker is in accordance with the state of circuit separation and closing, and check whether there is overheating at the connection point with the bus bar or the outgoing line. Inspect the dust on the surface of the low-voltage air circuit breaker in a timely manner to avoid affecting the operation and insulation performance. After the power failure, remove the arc extinguishing cover, check the integrity of the arc chute, and remove the smoke marks and metal powder on the surface. The shell should be intact and if it is damaged, it should be replaced in time.

circuit breaker

(3) Carefully inspect the low-voltage air circuit breakers' static and dynamic contacts. When any burr and metal particles are found on the contact surfaces, it should be cleaned and trimmed in time to ensure good contact. If the contact surface of silver tungsten alloy burns more than 1mm, it should be replaced in time.

(4) It is necessary to carefully check whether the contact pressure of the low-voltage air circuit breaker is overheated and fails, and timely adjust the position and pressure of the three-phase contacts to keep them closed at the same time in three phases to ensure that the contact surface is complete and the contact pressure is consistent. Slowly divide and close by hand, check whether the work status of the auxiliary contacts breaks and meets the requirements of “Maintenance Rules for Low-voltage Automatic Air Switches”.


(5)To comprehensively check whether the connection and spring movement of the low-voltage air circuit breaker tripper is normal, there should be no jamming in the action, the pole surface of the electromagnet should be clean and smooth, no rust, burr and dirt; see the various parts of the thermal element No damage, the gap is in line with the "low pressure automatic air switch repair procedures" requirements. If it is abnormal, it should be cleaned or adjusted. Lubricate the friction parts regularly to ensure their correct operation and reliable operation.

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