How to Maintain Circuit Breaker?

Figure 1: Maintaining a circuit breaker.

To make the circuit breaker to be in good conditions and prolong its service life, regular and proper maintenance is indispensable.

1. Keep it Dry and Clean

Moist or unclean air and tubes can give rise to the following results:
1) The moist gas is decomposed into mixed gases such as hydrogen and oxygen under the action of the arc, which destroys the insulation between the fractures after the main contact is broken. This will also reignite the arc and, in severe cases, cause the arc extinguishing chamber to burst.
2) The insulation strength of the support porcelain bottle and the arc extinguishing chamber is reduced, resulting in creeping discharge.
Therefore, install an oil-water separator on the intake pipe of the air storage cylinder of the main circuit breaker, and a drain valve at the lower part. Drain regularly during use to keep the air path clean.

2. Check the Main Components Regularly

The components need regular check so that the circuit breaker can serve longer and better.

2.1 Extinguishing Chamber

Figure 2: An arc extinguishing chamber.

Regularly check the status of the main contact overtravel and the dynamic contact return spring. Due to frequent opening and closing, the dynamic and static contacts will be worn due to mutual friction, resulting in reduced overtravel and reduced contact pressure.
When the overtravel is reduced to a certain extent, the dynamic and static contacts should be replaced. When the deformation of the return spring of the dynamic contact exceeds a certain limit, it must be replaced in time.

2.2 Non-linear Resistor

Keep the non-linear resistor porcelain bottle clean and well sealed. Change the desiccant in the porcelain bottle regularly. Detect the resistance value of the non-linear resistor. When the resistance value changes beyond a certain limit, it must be replaced in time.

2.3 Main Valve

Regularly check the matching size between the piston and the valve body. Replace the valve if the size doesn’t meet the requirement.

2.4 Vent Cock

The packing in the vent cock must be replaced regularly, and the ventilation volume of the vent cock must be checked and adjusted to the allowable range.

Figure 3: Maintaining a molded case circuit breaker.

2.5 Rubber Parts

The circuit breaker has a complex structure, and each component requires high sealing performance. To ensure good sealing performance, the rubber parts should be replaced regularly.

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