Selection and application of electronic earth leakage circuit breaker (ELCB)

Electronic earth leakage circuit breaker is mainly composed of zero sequence current transformer, electronic control leakage release and circuit breaker with overload and short circuit protection. When leakage current or personal electric shock occurs in the protected circuit, as long as the leakage current reaches the design selected action current value, the secondary winding of the zero sequence current transformer will output a signal, and the circuit breaker will act through the leakage release, so as to cut off the power supply for leakage and electric shock protection.

Leakage circuit breakers are generally divided into two pole, three pole and four pole, which are respectively used in different lines. Only the right choice and use can play its due role. Selection of circuit breaker: the rated voltage and current of the circuit breaker shall be greater than or equal to the normal working voltage and current of the line equipment; the leakage current of the line to be protected shall be less than or equal to the specified leakage protection current of the circuit breaker; the limit breaking capacity of the circuit breaker shall be greater than or equal to the maximum short circuit current of the circuit; the rated current of the overload release shall be greater than or equal to the maximum load current of the line It has a short breaking reaction time and can protect the circuit and equipment.

Use of circuit breaker: after the circuit is connected, check whether the wiring is correct. It can be checked by the test button. If the circuit breaker can be cut off correctly, it indicates that the leakage protector is installed correctly. Otherwise, check the circuit and remove the fault. After the leakage protector is put into operation, the user shall check whether the breaker operates normally through the test button after each period of time. The leakage, overload and short-circuit protection characteristics of the circuit breaker are set by the manufacturer and cannot be adjusted at will to avoid affecting the performance. The function of the test button is to check the operation state of the circuit breaker when it is closed and energized after a certain period of new installation or operation. Press the test button, the circuit breaker can be disconnected, indicating normal operation and continuous use; if the circuit breaker can not be disconnected, indicating that the circuit breaker or line is faulty, it needs to be repaired.

If the circuit breaker is broken due to the failure of the protected circuit (leakage, overload or short circuit), the operating handle is in the tripping position (middle position). After finding out the causes and troubleshooting, pull the operating handle down (i.e. put it in the "off" position) to make the operating mechanism "reclose" before closing (please note the different meanings of the three positions of the operating handle of the circuit breaker). After the circuit breaker is disconnected due to the short circuit of the circuit, the contact shall be checked. If the main contact is seriously burned or has a pit, it shall be repaired. The four pole leakage circuit breaker must be connected to the zero line to make the electronic circuit work normally. The load wiring of the leakage circuit breaker must pass through the load end of the circuit breaker, and it is not allowed that any phase line or zero line of the load does not pass through the leakage circuit breaker, otherwise it will generate artificial "leakage" and cause the circuit breaker to fail to close and cause "maloperation".