Pictorial view of single phase circuit breaker

Here is a pictorial view of a single-phase circuit breaker:

Single-Phase Circuit Breaker

Main Components:

  1. Main Contact: The main contact is the moving part that opens and closes the circuit. It is typically a spring-loaded contact that is connected to the breaker's operating handle.
  2. Fixed Contact: The fixed contact is the stationary part that the main contact moves against to open and close the circuit.
  3. Arc Chute: The arc chute is a metal plate that helps to extinguish the arc that forms when the circuit is interrupted. It is typically located above the main contacts.
  4. Operating Handle: The operating handle is used to manually trip the circuit breaker.
  5. Trip Unit: The trip unit is the electronic or mechanical device that detects overcurrent or overvoltage conditions and sends a signal to the main contact to trip.

How it Works:

  1. Normal Operation: When the circuit is normal, the main contact is closed, and the current flows through the circuit.
  2. Overcurrent or Overvoltage: When an overcurrent or overvoltage condition occurs, the trip unit detects the abnormal condition and sends a signal to the main contact to trip.
  3. Tripping: The main contact opens, breaking the circuit and interrupting the current flow.
  4. Arc Suppression: The arc chute helps to extinguish the arc that forms when the circuit is interrupted.
  5. Reset: Once the fault is cleared, the operating handle can be reset to close the main contact and restore power to the circuit.

Types of Single-Phase Circuit Breakers:

  1. Mechanical Circuit Breakers: These use a mechanical mechanism to trip the circuit.
  2. Electronic Circuit Breakers: These use electronic sensors and trip units to detect overcurrent or overvoltage conditions.
  3. Molded Case Circuit Breakers: These are compact, self-contained circuit breakers that are commonly used in residential and commercial applications.