Air circuit breaker (ACB)
Working function, Circuit diagram & Parts or components.


  1. what is Air circuit breaker(ACB).
  2. connection or circuit diagram of Air circuit breaker(ACB).
  3. Working function of Air circuit breaker(ACB).
  4. What is the types of parts or components of ACB.

1- What is the Air circuit Breaker (ACB):

Air circuit breaker(ACB): parts, working principle.

An air circuit breaker is an electrotechnical device for low voltage circuits like 415 or LT voltage. It is used for switching the power supply of the circuit and protect to the equipment against over current, short circuit, and earth fault.
It is designed for quenching the sparking during switching the heavy current such like as 800 amp to 10K amp so it is known another name air blast circuit breaker.

It is installed in LT panel or other 415 volt electrical panel and it is used for power suplly receiving for incommer panel and distributed to the feeder panel.

2- Circuit or connection diagram of ACB:

Air circuit breaker(ACB): connection, wiring diagram and parts

3- Working principle of ACB:

ACB is an electromechanical switching device on the range of 800A to 4000A which is used for protection of short circuit, overload, instantaneous and earth fault protection. Microprocessor based protection device are used for monitor and operation of overload, short circuit and earth fault relay in auto condition.

Due to heavy current when circuit breaker is operated then a large arc is produced and a arc chute chamber is used for arc quenching. Arc quenching process is done in arc chute.
For ACB smooth operation other accessories are used which is associated with ACB. Other accessories are shunt relies, closing relies, under voltage release and Microprocessor based protection device. Microprocessor based protection device are used

4- Parts of ACB:

An air circuit breaker is an electrical, mechanical, and electronic device. It is a group of different types of parts operating parts, protection parts, and moving mechanisms. The parts details are given below mentioned points.

1- Operating mechanism:

The operating mechanism is the important part of ACB which is used for the operation of on or off. This is operated as manually or electrically. In this on and off push button is installed for manually operating and closing coil and shunt coil is used electrically.

2- Protection release:

Microprocessors-based releases are used for ACB protection. It is used for overload, short circuit, and earth is set as per time set.
The release is an electrical device that is used for mechanical output in pre-defined set points. different types of release are used such as shunt release for tripping, Under-voltage release for voltage monitoring, closing release for breaker on condition, spring charging motor for mechanism spring of circuit breaker.

3- Cradle.

Cradle is used for rack in or rack out of ACB. Draw out ACB is installed on the cradle for moving the breaker in and out.

4- Interlocking.:

Interlocking is used for protection in ACB. It is electrically and mechanically types. in electrically the closing coil is interlocked and the operating mechanism is locked manually.

5- Terminal.

Terminals are used for power connecting and disconnecting of the circuit is used vertically, horizontally, and rear type.

6- Arch shoot.

The arch shoot is a chamber for quenching the arch during making and breaking contact in the breaker. It is made with many strips in a box so that the arc can be distributed.

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