FAQ of molded case circuit breaker

    Solution of opening and closing when the molded case circuit breaker is not in full phase

    1. If the molded case circuit breaker works under the condition of incomplete phase, the staff on site shall immediately solve this article to prevent potential safety hazards.

    2. During the conventional closing operation of molded case circuit breaker, the two phases of the molded case circuit breaker shall be closed. If one of the phases of the molded case circuit breaker is not closed, it shall be reopened immediately and then closed. If all the phases cannot be closed, the two phases of the closed molded case circuit breaker shall be separated immediately and the control power supply shall be cut at the same time.

    3. When the molded case circuit breaker is in normal operation, if the phenomenon of "stealing" occurs to the molded case circuit breaker or the two-phase operation of the molded case circuit breaker caused by the failure of the gate and the main line of the molded case circuit breaker accidentally touched by the staff on site, and one of the phases is disconnected, the molded case circuit breaker shall be closed immediately to avoid further dangerous accidents.

    4. If the molded case circuit breaker cannot be disconnected in the non full phase state, the power flow of this equipment shall be limited to the minimum immediately, and the following solutions can be adopted:

    A. if there is a technician in the work site, the technician shall disconnect the molded case circuit breaker immediately.

    B. if there are other molded case circuit breakers nearby that can replace the role of the original molded case circuit breaker, then the next molded case circuit breaker shall be used.

    C. if other operations are not allowed for electrical equipment under special circumstances, it is necessary to immediately cut off all associated molded case circuit breakers on the bus.

    Factors that have no effect after the molded case circuit breaker is closed:

    1. Check whether there is any error in the closing operation process.

    2. Check whether the power supply of the associated equipment under the molded case circuit breaker has been connected.

    3. Check whether the locking signal of molded case circuit breaker is restored.

    4. Check whether the protective action signal of molded case circuit breaker is restored.

    5. Check whether the closing coil of molded case circuit breaker is abnormal.

    6. There is a mechanical fault in the transmission or control mechanism of molded case circuit breaker.

    7. There are problems in the installation process and wiring mode of the electrical equipment associated with the molded case circuit breaker.

    The solution to the failure of molded case circuit breaker after closing the gate:

    A. first of all, determine whether the cause of ineffective closing of molded case circuit breaker is caused by line fault, and speed up the tripping time after protection. If so, immediately stop the operation and report to the dispatcher.

    B. determine whether the operation of the molded case circuit breaker is improper, and then check whether the molded case circuit breaker is missing the fuse. At the same time, check whether the reset speed of the molded case circuit breaker is too fast and the gate is not closed to the end. If the above phenomena exist, correct the gate position.

    C. check whether the voltage of the control and closing power supply exceeds the normal range. If so, adjust the power supply voltage on the molded case circuit breaker.

    D. if the molded case circuit breaker belongs to the second fault or the problem of the operating mechanism cannot be solved by itself, it shall be reported to the dispatching department and the superior department.