PHYSICAL TYPES OF CIRCUIT BREAKERS

 PHYSICAL TYPES OF CIRCUIT BREAKERS

All the circuit breakers presented so far in this chapter have been physically large, designed to control large amounts of power, and used a type of toggle operating mechanism. 

Not all circuit breakers are of this type. 

The circuit breaker in figure is physically large and controls large amounts of power but the operating mechanism is not a toggle. 

Except for the difference in the operating mechanism, this circuit breaker is identical to the circuit breakers already presented.

Circuit breakers used for low power protection, such as 28-volt dc, 30 amperes, can be physically small. 

With low power use, arc extinguishers are not required, and so are not used in the construction of these circuit breakers. 

Figure shows a low power circuit breaker of the push-button or push-pull

type. 

This circuit breaker has a thermal trip element (the bimetallic disk) and is nontrip-free. 

The push button is the operating mechanism of this circuit breaker.