Vacuum circuit breaker (VCB)
Working principle, Circuit diagram and Parts.

  1. Vacuum circuit breaker(VCB).
  2. Connection diagram of VCB.
  3. Working principle of VCB.
  4. Parts of VCB.

1- Vacuum circuit Breaker (VCB):

Vacuum circuit breaker(VCB): parts, types and their applications

This breaker is used for high voltage in the high tension (HT) panel. It works as a switching device manually or auto. It is also used to control and protect of electrical system from overload and short circuit. Where the vacuum is used for arc removing medium that breaker is called a vacuum circuit breaker.
It works as air removing from contact-making and breaker chamber. Both fixed and moving contract is closed in a vacuum chamber. The arc is extinguished with a high vacuum in the chamber. The range of voltage is 11 KV to 33 KV.

2- Connection Diagram of VCB:

Vacuum circuit breaker(VCB): connecttion diagram and working principle

3- Working principle of VCB:

The MCCB working principle is simple. Let us take three different fault conditions such as Overload, short circuit, and earth fault.

4- Parts of VCB:

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.

Go back to index ↑

Electrical and Mechanical Job Interview Training.
Get boost in your job or get new opportunity

Technical e book is used for storing data in soft formate which may be pdf, ms word or others as availability.

Electrical E-book

(Get important knowledge about industrial electrical, building maintenance in E-book )

HT system, LT system, Transformer, Electrical panel, Motor and Starter, Circuit breakers, Protection relays, Measuring meters.

Interview is a physical verbal communication activity which is performed between job seekers and employers so that skilled person could be selected.

Technical Interview

( Electrical system, Diesel generator, BMS, AC, Chiller plant,
UPS, WTP, STP, ETP, Fire and safety.)

electrician, maintenance supervisor, AC operator, chiller plant operator, DG operator, BMS operator, Shift engineer, Maintenance engineer, technical executive, sr. engineer, assistant facility manager,


Learn Fast and Improve Your Skill in Electrical Field Basic and practical theory, repair and maintenance, protection and testing.

For any query :- write to us as below mentioned email ..

For official :-

For technical information :-

For interview preparation :-
Subscribe for Get Latest Post Updates in Your Email Inbox
Join Free Email Service