The Reasons For The Burning Out Of The Opening Coil Of Small Circuit Breakers

A small circuit breaker is a commonly used electrical device switch, suitable for overload and short circuit protection of AC 50/60Hz rated voltage 230/400V, rated current up to 63A lines, and can also be used for infrequent operation and switching of lines under normal circumstances. The overall structure is compact, the external volume is small, the weight is light, and it has good conductivity, insulation, functionality, etc. It is mainly used in various places such as industry, commerce, high-rise buildings, and civil residences.

 

In the use of small circuit breakers, the failure of the opening coil is one of the common faults, and the main reasons for the burning of the opening coil are as follows:
1. Mechanical failure of the opening mechanism
The mechanical failure of the internal mechanism of the small circuit breaker results in loose coils, causing the electromagnetic core of the small circuit breaker to shift during opening, affecting the normal opening process and causing the internal core to jam during opening, causing the opening coil to burn out. Or due to the short travel of the iron core, when the power supply of the opening circuit is connected, the iron core cannot open the release mechanism, causing the coil inside the small circuit breaker to be energized for a long time. Under the action of high-intensity current, it exceeds its bearing range, causing the coil to burn out.

2. Improper adjustment of travel and auxiliary switch contacts
We know that when adjusting the parameters of the small circuit breaker, the initial state of the small circuit breaker opening will be changed. However, due to the lack of corresponding adjustment of the initial state of the auxiliary switch opening position, this will cause the auxiliary switch to be unable to switch the opening circuit normally when the small circuit breaker needs to open due to a fault in the circuit, causing the internal opening coil to burn out due to prolonged power supply.

3. Protection and control device malfunction
One of the reasons for the burnout of the opening coil is the abnormal situation of its protection and control device, which will greatly affect the normal opening process. As the opening command is issued by the protection and control device to achieve the closing of the small circuit breaker, if the opening relay in the device is abnormal or the auxiliary switch contact of the opening control circuit has a large stroke, it will affect the normal issuance of the opening command of the protection and control device, causing the opening command to not exit in time, and thus causing the internal opening coil to burn out.

4. The resistance of the opening circuit is too high
There is a problem with the opening coil itself. Due to long-term operation, the insulation performance is reduced, or the control circuit wire diameter is too small, causing a large resistance, resulting in a significant voltage drop in the opening control circuit. The voltage cannot reach the action value of the coil opening voltage, causing the coil to burn out due to prolonged electrification.

5. Refusal to open small circuit breakers
When the control circuit of a small circuit breaker is normal, the failure of the switch device to open is all due to mechanical mechanism failure. The connecting rod mechanism has abnormal problems, such as the failure of the protective locking mechanism, which leads to severe overload of the coil and burns out the opening coil. Or it could be a mechanical malfunction, with a problem with the connecting rod mechanism and improper adjustment of the vertex, resulting in the insufficient force at the top of the opening rod to cause the mechanism to trip, causing the opening coil to burn out due to prolonged power supply.

Therefore, when using small circuit breakers, users should regularly maintain them. Through the maintenance process of small circuit breakers, hidden dangers and problems in the device should be discovered, and corresponding measures should be taken to solve them. If serious damage is found or the product's service life is expired, a new small circuit breaker product should be replaced to ensure the stability of the distribution system operation.