Monday, March 19, 2012

Miniature Circuit Breakers (MCBs)

  • Miniature Circuit Breakers (MCBs) are generally used for low Picture1current application
  • This a simple circuit breaker that is used to break the circuit in case of over current
  • MCBs are most commonly used in protecting equipment like lamps, heaters, air-conditioners, motors and so on
  • MCBs work on the principle of thermo-couple action
  • When a current higher than the rated current flows through it, the thermocouple is heated up and trips the MCB
  • MCBs are specified as for example : 415 V, TPN (Three Pole Neutral), 32A, 10KA(breaking capacity) and C curve
  • There are number of types of MCBs viz :
  • 1phase,Single pole
  • 1phase 2 pole
  • 3 phase 3 pole
  • 3 phase 4 pole
  • Miniature Circuit Breaker – Inner view

    1.Actuator lever - used to manually trip and reset the circuit Picture2breaker.

    2.Actuator mechanism - forces the contacts together or apart.

    3.Contacts - Allow current when touching and break the current when moved apart.


    5.Bimetallic strip

    6.Calibration screw - allows the manufacturer to precisely adjust the trip current of the device after assembly.


    8.Arc divider / extinguisher

No comments:

Post a Comment

Electrical engineering Community - All Forums