Common Faults of Circuit Breakers and Their Elimination Methods

The contact of a certain phase of the circuit breaker fails to close.
(1) Check if the connecting rod is broken or deformed.
(2) For circuit breakers of the current-limiting type, it is necessary to check whether the angle between the detachable connecting rods of the disconnection mechanism has deformed.
2. The circuit breaker cannot be closed by manual operation.
(1) Check if there is no voltage on the overvoltage release device. If necessary, replace the coil.
(2) Check if the clamping device of the armature is deformed. If necessary, adjust the spring.
(3) Check whether the storage spring has deformed, causing a reduction in spring force. If necessary, replace it.
(4) Check whether the reaction force of the counteracting spring is too large.
(5) Check if the connecting rod of the manual trip device is deformed.
(6) Check whether the circuit of the leakage circuit breaker is leaking electricity or grounded.
3. The electrically operated circuit breaker cannot be closed.
(1) Check whether the control power supply voltage is too low or whether the power capacity is insufficient.
(2) Check whether the limit switch for motor interruption is not disconnected when it is in the disconnected position.
(3) Check whether the stroke of the electromagnet is too short when it is opened.
(4) Check whether the control circuit lines are poorly connected, and inspect whether the adjustment components or capacitors are damaged.
4. The circuit breaker has excessively high temperature rise.
(1) Check if the contact pressure of the contacts is too low. Adjust the pressure of the contact spring or replace the contact spring.
(2) Check whether the connecting screws of the main circuit are loose and if there is any oxide layer.
(3) Check whether the contacts of the circuit breaker are severely worn.
(4) Check whether the contacts of the circuit breaker have been scorched by the arc and if any metal particles have been formed. Such particles should be removed and smoothed out.
5. The de-energizing trip device fails to disconnect the circuit breaker.
(1) Check whether there is any break in the coil or if there is a short circuit between the turns.
(2) Check if the power voltage is too low.
(3) Check whether there are any faults in the wiring or if the screws are loose.
(4) Check whether the contact surface is too large.
6. The under-voltage trip device cannot cause the circuit breaker to trip immediately.
(1) Check if the trip force is too small. Adjust the spring to increase the pulling force.
(2) Check if the spring force of the energy storage device has decreased.
(3) Whether the mechanism is stuck, such as being rusted or deformed.
7. After closing the circuit breaker, it was disconnected after a certain period of time.
(1) Check whether the long-delay setting value of the overcurrent trip device is too small. If it is, it should be adjusted.
(2) Check whether the electronic overcurrent trip device components are damaged.
8. The circuit breaker immediately trips when the motor is started.
(1) Check whether the instantaneous setting value of the overcurrent trip device is too small. If it is, it should be appropriately adjusted.
(2) Check whether the components of the electronic overcurrent trip device are damaged.
9. The noise of the under-voltage trip device is too loud.
(1) Check whether the force of the counterforce spring is too large.
(2) Check if there is any oil residue on the working surface of the iron core.
(3) Check if the short-circuit ring has broken.