The active contacts, static contacts, auxiliary contacts, coils, short-circuit rings, interrupter covers and other parts of low-voltage moulded case circuit breakers are prone to failure and cannot simply be closed when the equipment is off-load fault. First check the appearance, interrupter cover and other parts for burnout, if so, the bad parts should be removed for inspection, repair or replacement and stain removal.

High temperature leads to circuit breaker tripping

Low-voltage plastic-case circuit breakers installed in outdoor distribution boxes, high summer temperatures, coupled with the load, the temperature inside the box will rise above the applicable working environment of the circuit breaker. The circuit breaker overload protection thermal bimetallic element is rolled from two metals with different coefficients of thermal expansion. When the bimetal senses the heat generated by the overload current, the active layer bends towards the passive layer. If the ambient and temperature around the circuit breaker exceeds the reference temperature, the circuit breaker will operate earlier and lose its overload protection function even if the current passing through is not overloaded and the normal rated current is less than the rated current. Therefore, it is necessary to increase the rating of the circuit breaker, reduce the operating current and carry out on-site heat dissipation.

Circuit breaker fault tripping when starting a Chinese motor

1, is a starting motor with a load. When the motor is started with a load, it increases the current and trips the circuit breaker. Before starting the motor, check whether the motor load is cut off and start the motor when there is no load on the motor.

2, When the voltage is low, the current spikes when starting the motor, causing the starting current to increase and causing the circuit breaker to trip. The voltage variation range at the receiving end of the user must not exceed, three phase low voltage user rated voltage + 7% -7 x. When the voltage measurement value exceeds the specified value, the transformer tap and load need to be adjusted.

3, The rectification multiplier for the instantaneous protection of the circuit breaker is too small. Reasonably adjust the rectification multiplier of the circuit breaker instantaneous protection to be consistent with the operational requirements of the equipment on site. Fourth, the choice of plastic case circuit breakers is not the power type, resulting in circuit breaker tripping. Select the correct plastic case circuit breaker according to the use of the equipment.

Running circuit breakers from time to time tripped fault phenomenon has occurred to develop reasons and measures.

1. the selected connecting cable or copper rod cross section is too small to generate heat easily, therefore the circuit breaker trips.

2. It is the tightening of the fastening bolts at the load end that leads to poor contact and a lot of heat, causing the circuit breaker to trip.

3. is a load overload tripping.

Low-voltage molded case circuit breaker parts damage treatment

1. is the main and secondary contacts. Surface burns caused by serious should be replaced to avoid grinding too much and reduce the working pressure of the student contact social surface.

2. auxiliary contacts. Use fine sandpaper (cloth) to polish; contact surface shall not be greasy.

3. Interrupter. Carbonization phenomenon should be scraped clean, moisture phenomenon should be dried, damage should be re-matched, the installation angle should be correct so as not to hinder the contact action.

4. It is a short circuit ring and coil. Damaged ones should be replaced in time.

5. It is a soft connection piece. The replacement of damaged components of the equipment should be carried out in time.