Analyze the cause of failure of circuit breaker cl

Analyze the causes of circuit breaker closing failure

common faults of circuit breaker closing failure, especially in the operation of electrical equipment. If it is handled improperly and delays the power transmission time, it will cause a large area of power failure and cause great losses to production

then why does it cause the closing failure of the circuit breaker? In fact, there are many reasons for the failure, such as improper operation method during closing, the voltage quality of closing bus can not meet the requirements, the disconnection of control circuit and mechanical failure, which can be summarized into two aspects: one is the failure of electrical secondary circuit, and the other is the mechanical failure of switch and operating mechanism. Therefore, when the circuit breaker refuses to close, the staff should distinguish the electrical secondary circuit fault from the mechanical fault of the operating mechanism in order to make a correct judgment. The main basis for distinguishing the two is to see the indication of red and green lights, the change of flash and the action of closing contactor and closing iron core

(1) when the control switch is turned to the closing position, the traffic light indication does not change, the green light still flashes and the red light does not light, the closing ammeter does not swing, the horn rings, and this phenomenon has high temperature and chemical resistance. It has shown that the operating mechanism does not act, and the problem is mainly in the secondary circuit of electricity and gas. The closing fuse is blown or has poor contact

② the voltage of the closing bus is too low. According to the requirements of the operation specification of high voltage circuit breaker, when the closing coil of the closing power supply operated by the electromagnetic mechanism is energized, the terminal voltage shall not be less than 80% of the rated voltage and the maximum shall not be higher than 110% of the rated voltage. If the voltage of the closing bus is too high or too low, the circuit breaker will refuse to close

③ poor contact of closing operation circuit elements. For example, the poor contact of the control switch, the auxiliary switch contact of the circuit breaker and the contact of the anti tripping relay will make the closing operation circuit impassable, so that the coil of the DC closing contactor cannot be energized and closed, and the closing operation circuit will be rejected when starting. ④ if it is operated back, it will also provide inexhaustible development power for the extruder industry. Loose wiring terminals in the circuit, or disconnection of closing contactor coil, etc. will also cause the secondary circuit to be blocked and refuse to close.

(2) when the control switch is turned to the closing position, the green light is off and the red light is not on. When the control switch returns to the closing position, both the red and green lights are not on, and an accident sound signal is reported. At this time, it indicates that the switch is not closed at all, which may be due to the fusing of the operation fuse or poor contact during operation. If there is no accident sound signal, the closing ammeter indicates that there is swing, there is load current on the line, and the mechanical opening and closing pointer is also in the closing position, it indicates that the switch is in the closing position. At this time, check whether the bulb, lamp holder, operating fuse and normally open auxiliary contact of the circuit breaker are in poor contact. If the above conditions occur, the operating operator shall disconnect the circuit breaker and close it after eliminating the fault

(3) when the control switch is turned to the closing position, the green light turns off and then turns on again or flashes, and the closing ammeter swings. There may be two reasons: first, the closing power supply voltage is too low, resulting in the failure of the operating mechanism to lift the switch lifting rod and the incomplete action of the transmission mechanism; The second is the improper adjustment of the operating mechanism, such as the overtravel of the closing iron core or insufficient buffer gap, improper adjustment of the top rod of the closing iron core, etc. In this case, professional maintenance personnel should be invited to repair

(4) when the control switch is turned to the closing position, the green light goes out, the red light goes out again, the green light flashes, and the closing ammeter swings. This situation indicates that the switch has been closed. Due to the mechanical failure of the mechanism, the maintenance mechanism fails to keep the circuit breaker in the closing position, such as the closing support has a large slope or does not reset; The buckle size of the tripping mechanism is not enough; The four connecting plate mechanism has not passed the dead center; The closing power supply voltage is too high, etc

(so as to improve the production efficiency 5) if the switch jumps when the electromagnetic operating mechanism is closed, this phenomenon is mostly that the switch is normally closed and the auxiliary contact is opened too early; Or it is caused by excessive closing times during transmission test, resulting in overheating of closing coil

in short, as long as we observe carefully in our daily work, pay attention to accumulate experience and develop the good habit of using our brains frequently, it is very easy to solve the phenomenon of circuit breaker refusal to close