Refrigerator Troubleshooting. Circuit breakers

Fuse element provides protection destroying itself and must be replaced. It cannot be checked without destruction; therefore, the test result will not apply to the replacement.

Circuit breaker (CB) is the automatic switch, which will be opened in the event of excess current and can be closed again when the problem is corrected. The switch contacts are closed against spring pressure, and already closed latch agreement. A slight movement will latch release contacts quickly under spring pressure to open the scheme; only excessive currents will work.

Two types: thermal and magnetic.

Thermal

Load current is passed through a small heater, the temperature of which depends on the current, borne by him. The heater will keep warm, and a bimetallic strip. The increases in current flows bimetallic strip deformation to travel latch mechanism.

Some delay is due to the transfer of heat generated by the load current bimetallic strip. Thermal trip are suitable only for small loads on the long term. Excess heat caused by heavy overload can buckle and distort the bimetallic strip.

Magnetic

The principle used in this type of magnetic force of attraction, established by the magnetic field of the coil carrying the load current. Under normal currents, magnetic fields is not strong enough to engage the latch. Overload currents will increase the power of attraction and work with the latch to travel to the main contacts.

Typical magnetic circuit breaker is shown in Fig. 101.

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