Types of ACB (Air Circuit Breaker)

Industries use 6 types of ACB: pole type, current capacity type, fix or drawout type, breaking capacity type, operation type, and protection type.

Types of ACB:

Different types of Air Circuit Breakers (ACBs) are available for various applications, such as pole, current capacity, installation type, and breaking capacity. Details of the different types of ACBs are given below.

  1. According to pole type
  2. Current Capacity type
  3. Mounting- Fixed or draw out type
  4. According to Breaking Capacity
  5. EDO and MDO type ACB
  6. Protection type ACB

1. Pole Type ACB:

A pole of a circuit breaker refers to the part of the breaker that is associated with one conducting path in the main circuit.

Three-Pole ACB –The circuit breaker with a 3-pole has three separate conducting paths. It is used for 3-phase, 3-wire electrical system.

Four-Pole ACB –The 4-pole ACB has four separate conducting paths. It is used for 3-phase, 4-wire electrical system. It is possible to isolate the neutral with 4-pole ACB.

2. Types of ACB: According to the Current Capacity

The current rating capacity of ACBs ranges from 400A to 6300A. Below are the details:

S.NCurrent Rating
3. Fixed or Draw Out Types of ACB

Fixed Type- Fixed type ACB is mounted on the panel’s chassis and cannot be drawn out. The draw-out mechanism, such as the cradle and safety shutter, are not used. It is a low-cost ACB compared to a draw-out ACB.

Draw-out type – Draw-out air circuit breakers (ACBs) are widely used in industries. They can be easily moved on a cradle for maintenance purposes, both inside and outside. The best part is that they can be replaced without changing the base chamber, meaning that faulty ACBs can be replaced with new ones quickly and easily.

4. Typess of ACB: According to Breaking Capacity

As per the breaking code, the breaking capacity of ACB ranges from 25KA to 200KA. The details are given below.

Sr.No.Breaking CodeBreaking value
1B25KA/440 Volt
2F36KA/440 Volt
3N50KA/440 Volt
4H70KA/440 Volt
5S100KA/440 Volt
6L150KA/440 Volt
7R200KA/440 Volt
8HB175KA/690 Volt
9HB2100KA/690 Volt
10K10KA/1000 Volt

5. According to Operation as EDO & MDO Type:

ACB has two types of operations: EDO (electrically draw out) and MDO (mechanically draw out).

EDO Operation: The EDO-type ACB can be easily operated remotely from any distance through a networking system. It mainly has three functions, which are listed below:

  • Spring Charging:- In auto mode, an electrical motor charges the spring.
  • Closing Coil: The system can be operated either via a TNC or remotely through a PLC or BMS system.
  • Shunt Coil or tripping Coil: The shunt or tripping coil can be operated using TNC or remotely through PLC or BMS.

When the ACB is charged and closed using the electrical release, it is called the EDO type. Spring charge motors are used for spring charging, and a closing coil is used for closing the breaker.

Mechanically operated draw out (MDO)-The MDO type ACB can only be operated manually and cannot be operated through any other source. When the ACB is charged manually without the spring charge motor and closed without the closing coil, it is called an MDO-type ACB. Two press buttons are used to start and stop the ACB. To switch it on, we need to press the ‘on’ button and to stop it; we have to press the ‘stop’ button.

6. According to Protection Type ACB

Thermal-magnetic trip- Thermal-magnetic trip units are effective in safeguarding against overcurrents and short circuits using traditional methods.

Electronic Trip: Intelligent operation and reflex tripping are combined in electronic trip units, which are faster and more accurate.

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