Common failures and troubleshooting methods of low voltage circuit breakers

Promulgator : TAIXIDate : 2018-09-05Views : 93

Low voltage circuit breakers, formerly known as air circuit breakers. It is mainly used in circuit overload, short circuit and under-voltage and otherr abnormal circumstances such as automatic break off the circuit, cut off the power supply. Common failures of lv circuit breaker are unable to close. This kind of fault occurs because the undervoltage release has no voltage or the coil is damaged, the reaction force spring force is too big, or the mechanism can not reset and reset. The repairing method is to check the voltage of the power supply, replace the coil or readjust the spring. If the mechanism can not be reset and reset, the contact surface should be adjusted to the specified value.

Too high temperature rise of c45n circuit breaker is a common fault. The reason is that the contact pressure is too low. At this time, the contact pressure can be adjusted or the spring should be replaced. Sometimes the fault may also be caused by serious wear and tear on the contact surface or by serious poor contact. A new circuit breaker should be replaced at this time. If the temperature rise is too high, it is due to the loosening of the connecting screws of the two conductive parts, and it should be re tightened.

When the current has reached a set value, and the c45n circuit breaker can not break normally when the fault, should check whether the thermal release of the bimetal sheet is damaged, if damaged, should be replaced. Then check whether the distance between the armature and the core is too large or whether the coil is damaged, then adjust the distance between the armature and the core or replace the circuit breaker. Sometimes the circuit breaker will break immediately when starting the motor. This may be because the setting value of the overcurrent release is too small, or because of the vibration in operation, the setting value has changed. The instantaneous setting value of the over current release can be adjusted to the prescribed value. If some parts are damaged, the releaser can be replaced.

When there is noise in the voltage loss release of the lv circuit breaker, it can be observed whether there are rust spots or oil stains on the surface of the iron core, if there is, it should be erased. Or observe whether the short circuiting ring is broken, and replace the armature and iron core. You can see if the force of the reaction spring is too large. If it is too large, it should be readjusted.

Low-voltage circuit breaker is a kind of complicated electrical apparatus. In addition to correct selection and adjustment, it must be properly maintained to ensure its safe operation.

Working principle of lv circuit breaker

Low-voltage circuit breaker has a variety of protection functions (overload, short circuit, under-voltage protection, etc.), adjustable operating value, high breaking capacity, easy operation, safety and other advantages, so it is widely used.

The main contacts of c45n low voltage circuit breakers are operated by manual operation or by electric switching. After the main contact is closed, the free tripping mechanism locks the main contact on the closing position. The coil of the overcurrent release and the thermal element of the thermal release are in series with the main circuit, and the coil and the power supply of the undervoltage release are in parallel. When the circuit is short-circuited or seriously overloaded, the armature of the over-current release closes and the free release mechanism acts, and the main contact disconnects the main circuit. When the circuit is overloaded, the heat element of the thermal release causes the bimetal sheet to bend and pushes the free release mechanism to move. When the circuit is under voltage, the armature of the undervoltage release is released. It also enables the free tripping mechanism to act. Split-excitation tripper is used for long-distance control. In normal operation, its coil is power-off. When distance control is needed, press the start button to make the coil energized and the armature drives the free tripping mechanism to disconnect the main contact.