Circuit breaker releases stored energy

How do solid state circuit breakers operate?

Solid state circuit breakers operate by relying solely on the solid state switch to carry nominal load and to interrupt current. Since the electric arc is eliminated, another mechanism is needed to dissipate the stored energy in circuit inductance. This is typically achieved via parallel connected metal-oxide varistors (MOVs).

How does a DC circuit breaker work?

In a DC application, a circuit breaker works by developing substantial voltage across it to help drive the current in the circuit to zero during current interruption. It also dissipates stored energy within the circuit inductance to limit the magnitude of the voltage spike caused by the sudden change in current flow.

How does a circuit breaker reset work?

Resetting: After the fault is resolved, the circuit breaker can be reset manually or automatically, allowing the current to flow again. Re-establishment of Contacts: Resetting the circuit breaker reconnects the fixed and moving contacts, allowing current to flow through the circuit again.

Why are circuit breakers important?

Power transmission: Circuit breakers protect transmission lines from faults, lightning strikes, and switching surges. They also allow for the sectionalizing and load-shedding of power systems.

How does a vacuum circuit breaker work?

A vacuum circuit breaker employs a vacuum to extinguish electric arcs. The vacuum has high dielectric strength and low arc resistance, so it is an effective medium. The breaker’s contacts are housed within a ceramic or metal chamber, which is then evacuated to a very low pressure.

Can a circuit breaker be opened or closed?

Under normal operating conditions, the circuit breaker’s arms can be opened or closed to switch and maintain the system. To open the circuit breaker, you only need to apply pressure to a trigger. Whenever a fault occurs in the system, the breaker’s trip coil gets energized, causing the moving contacts to separate, thus opening the circuit.