"With the continuous improvement of consumers' requirements for environmental protection, grade and function of automotive interior, the failure causes and treatment of CD10 electromagnetic operating mechanism
Abstract: This paper summarizes several common failure causes of CD10 circuit breaker electromagnetic operating mechanism, and puts forward the treatment methods in case of failure.
key words: electromagnetic mechanism failure treatment operating mechanism is an important part of circuit breaker, and the working reliability of circuit breaker is to a great extent It depends on the action reliability of the operating mechanism. The analysis of circuit breaker accidents shows that the accidents of circuit breakers caused by operating mechanism account for more than 60% of the total accidents, which shows how important the operating mechanism plays in the working performance and reliability of circuit breakers. 1 closing failure 1.1 mechanical reasons 1.1.1 the limit screw is too high (too low) and the electric closing failure, connecting rods 2 and 3 are not in line, as shown in Figure 1. The limit screw (adjusting screw) is loose, resulting in too high (or too low), as shown in Figure 2. When the closing is stressed, the two connecting rods bend upward (downward) to make the closing iron core do virtual work, as shown in Figure 3. If the two connecting rods are just at the horizontal position, the closing is too sensitive. During the closing process, the iron core ejector rod pushes the roller up to the end position, and the roller jumps off the ejector rod, making the closing fail. Therefore, the height of the limit screw is the key to the success of closing. Check, adjust and tighten the screw rod so that the connecting rods 2 and 3 are basically in line and slightly smaller than L80? 1.1.2 the stroke of the closing core ejector rod is small, and the impulse force is insufficient. The electric closing fails. Observe that the closing iron core is not high enough at the moment of closing. The stroke of the closing core ejector rod should be 1.5~2.5 mm higher than the support at the closing end position, as shown in Figure 4. Manually close the switch slowly with the force bar, and the stroke of the closing iron core ejector rod should be within the above range. 1.1.3 the speed of closing is also achieved by changing gears. The iron core of the friction and wear tester with different constant speeds is jammed, and the closing iron core cannot move up and down freely in series during the closing process, or the iron core cannot fall down after closing. The sleeve in the closing coil is improperly installed or deformed, and the tightening force is inconsistent, resulting in the non vertical iron core, large friction resistance, and cannot move up and down freely in series. Even if the iron core is forced to rise under the action of electric power, it is often stuck and cannot fall down. Reinstall to make the tightening force of the sleeve uniform. Then manually close the switch with the booster rod and open the switch several times until the action is flexible. 1.1.4 if the bearing does not rotate properly, when closing manually with the force adding rod, the friction resistance of the rotating parts of each bearing is large, and it cannot rotate flexibly. During operation, the rotating parts of each bearing lose lubrication for a long time, which increases the friction resistance and weakens the kinetic energy during the closing process. For example, when the closing iron core reaches the end position, the support 7 (see Figure 1) cannot quickly return to support 10. The rotating parts of each bearing are often lubricated to make it move freely. 1.1.5 the closing support trips. When the closing iron core reaches the termination position, the closing support 7 is in close contact with 10, but it cannot support, resulting in closing failure. The slope of closing support 7 is too steep. Adjust or replace the closing bracket to make the supporting part tend to be flat. 1.1.6 the iron core cannot go up during the closing process of transmission machinery failure, resulting in closing failure. The reason: ① the transmission mechanism (1) the beam operates normally, and the connecting rod is twisted and deformed; ② The pin of the connecting shaft falls off. The deformed connecting rod should be adjusted and the shaft pin reinstalled. 1.2 electrical reasons 1.2.1 the closing circuit is blocked, the green light is not on (see Figure 5), the auxiliary contact (normally closed) of the oil circuit breaker is not closed, the operating fuse is fused, the closing circuit is disconnected, the normally closed contact of the anti tripping circuit is poorly contacted, and the contact of the closing handle is poorly contacted, etc. First, check whether the operating fuse is fused, and then manually close it slowly, and observe whether the normally closed contact of the auxiliary switch of the oil circuit breaker acts correctly. Otherwise, adjust the screw connected with it. This part is the weakest link and the place with problems. Then use a multimeter to check all components of the circuit and find out the fault point. 1.2.2 the DC voltage is too low. Although the mechanism acts after the closing command is issued, it cannot be closed. If the DC power supply voltage is lower than 170 V, it is less than 80% of the rated voltage of the closing coil. It is caused by one-phase breakdown of silicon rectifier elements or one-phase fusible link fusing on the AC power side of rectifier. Operation experience shows that the three phases of the AC input power supply of the three-phase bridge rectifier are normal. When the input voltage is 380 V, the DC output voltage is 220 v. If one phase fuse on the AC side is blown or one phase of silicon element is broken down, the output DC voltage is 170 v. If the two-phase fuse on the AC side is blown, the output DC voltage is zero; In addition, the power supply voltage may be too low. Check whether the fuse on the AC power side of the three-phase bridge rectifier is blown and whether the silicon element is broken down. The fuse and silicon element should be replaced or the DC power supply should be increased to meet the service voltage of the closing coil. 1.2.3 at the moment of electric closing when the relay contact of the protection circuit is connected, the red light flashes, indicating that the oil circuit breaker has been closed, but the instantaneous red light goes out, the green light is on again, and the oil circuit breaker is opened again. At the same time, observe the action of the tripping core. This abnormal phenomenon of instantaneous opening after closing often occurs in the current relay used for quick break (1.2lj) overcurrent (3.4lj) protection (see Figure 5). Because the protection setting adjustment handle is in the front half of the dial, the spring reaction distance is small, so that the normally open contact does not return after the accident trip, resulting in contact adhesion. The tripping circuit is charged for a long time, or the relay contact on the switch cabinet is momentarily connected by vibration at the moment of switch closing. Sometimes it also occurs in the contact of time relay (SJ) acting on the tripping of oil circuit breaker