BULK OIL CIRCUIT BREAKER I visit oil circuit breaker. It was bulk oil circuit breaker.

In this C.B oil is used for arc extinction all parts of this C.B are immersed in

oil. The oil is used for C.B is mineral oil. It has highly dielectric strength.

Its rated current capacity is 23 A.

Its breaking capacity is 68 kv.

It was made rexroure company.

It was connected at 66 Kv line.

Its construction is contains of tank. The oil and all parts of C.B covered by

tanks.

The moving contacts connected by a piston and piston moves up and down

with the tension rod. The tension rod and piston immersed in oil completely.

The fixed contact connected with copper conductor. The bushing is used for

passes the conductor under their middle holes. The bushing made by insulator

that one connected in series with each other.

The two bushings connected with conductor and conductor is connected with

fixed contact.

There is also a cover provided around the fixed contact called arc control

device.

In normal condition the fixed and moving contacts closed with each other and

arc control device covered both contacts.

WORKING

In normal condition fixed and moving contact are tough with each other and

current passes through these contact and C.B work regularly.

When fault across then are produced between contacts and due to arc pressure

the both contacts separate with each other then some oil flow between

contacts and oil will covert into gases due to heat of arc. These gases also

between both contacts. These gases moves upward and store in upper space

of oil C.B.

During this process the more quantity of oil flow between contacts and it

becomes increases dielectric strength of medium between contacts. When

dielectric strength of medium becomes increase then arc will not strike and

due high value of resistance the flow of current will be stop and arc will be

extinction in this position the C.B will be tripped and disconnect the supply

path to given circuit.

Vacuum circuit breaker:

The vacuum C.B is a superior dielectric and good medium of arc extinction.

There is no need of extra medium to arc extinction.

Moving contacts have slightly weight.

During operating process the moving contacts covered distance only some

millimeter.

There is a some quantity of energy for operating mechanism.

The mechanical pressure on contacts gets from spinning.

Working

In vacuum C.B when contacts separates each other then arc will be produced.

This C.B use vacuum is a best dielectric.

The arc can not remains in a best vacuum.

During the separation of contacts the absorb gases becomes ionize due to

heating on the contacts the contacts material provides charge partial due to

field emission. This charge partial increase process of arc.

When current becomes zero then arc will also extinction and medium gets

the dielectric strength and vapor density becomes to minimum.

Construction

The outer envelope is made glass due to jointing it to metallic end caps and

glass enveloped also provided the faculties from out side protection. if its

color becomes white from its original finish of silvery mirror, then it indicator

that baffle is losing to vacuum.

A splitter shield made of stainless steel, placed between conducts, this also

prevent metal vapor reaching the envelope. Inside suppter shield there are two

contacts one fixed and other is moving. The moving contact short distance

with respect to operating voltage.

Metallic bellows used to move the moving contact.

The moving contacts fix with spring.

The metallic bellows moves upward and downward during opening and

closing operation.

11Kv Busbar Outgoing C.B:

It is made of PEL PAK LAHORE PAKISTAN.

Date of installation 14/07/2002.

Rated 12Kv.

Breaking capacity 25KA.

Weight 143 Kg.