The Causes Of Circuit Breaker Closing Failure

The reasons for the ineffective closing of circuit breakers are various, such as poor operation during closing, failure to meet the specified voltage quality of the closing bus phase, control circuit disconnection and equipment failures. However, specifically, there are only two reasons: common faults in the secondary circuit of electrical equipment, and common faults in the organization of power switches and operation organizations.

When a circuit breaker fails to close, as an operator, one should be able to distinguish whether it is a common fault in the secondary circuit of electrical equipment or an equipment failure caused by the operating organization. The key to distinguishing between the two is to see the red and green light markings, the flashing transition status, and the posture of the closing AC contactor and closing transformer core.
(1) When the control switch is turned to the "closing" position, the traffic light indication does not change, the green light still flashes but the red light does not light up, the closing ammeter does not shake, and the speaker sounds. This type of situation indicates that the operating organization does not have posture, and the key problem lies in the intelligent secondary circuit breaker of the electrical equipment, which may cause the commercial fuse to melt or have poor contact when closing.

(2) When the control switch is turned to the "closed" position, the green light goes out and the red light does not light up. When the control switch returns to the "closed" position, both the red and green lights do not light up. In addition, a safety accident speaker data signal is provided, indicating that the power switch has not been closed at all. It is likely that during operation, the commercial insurance has melted or had poor contact. If the safety accident speaker data signal is not provided, the closing ammeter mark is shaking, and there is also a load current on the route. Moreover, the mechanical equipment opening and closing meter needle is also in the "closed" position, indicating that the power switch is in the "closed" position. At this time, it is necessary to check the light bulb, socket, operating commercial insurance and its circuit breaker. Is the contact between the opening and closing auxiliary contacts poor? If the above situation occurs, the operating personnel should disconnect the circuit breaker, clear common faults, and then close it again.

(3) When the control switch is turned to the "closing" position, the green light will turn off and then turn on again or flash, causing the smart power circuit breaker to have shaking of the closing ammeter. There are likely two reasons for this: first, the closing power supply voltage is too low, causing the operating organization to be unable to lift the power switch lever, and the transmission mechanism posture is not completed; second, the operating mechanism is not adjusted properly, such as the closing transformer core exceeding the travel range or insufficient buffer gap, and the small chain adjustment of the closing transformer core is not good. In case of such situations, technical maintenance personnel should be invited to repair.