The voltage appearing across the contacts after opening of the circuit breaker is called______voltage.

The arcing contacts in a circuit breaker are made of

A

copper tungsten alloy

B

porcelain

C

electrolytic copper

D

aluminium alloy

The arc voltage produced in A.C. circuit breaker is always

A

In phase with the arc current

B

Lagging the arc current by 90°

C

Leading the arc current by 90°

D

None of the above

In order that current should flow without causing excessive heating or voltage drop, the relay contacts should

A

Have low contact resistance

B

Be clean and smooth

C

Be of sufficient size and proper shape

D

Have all above properties

The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to

A

lubricate the contacts

B

insulate the contacts from switch body

C

extinguish the arc

D

all of the above

E

none of the above

In a coil ignition system of petrol engines, a condenser is connected across the contact breaker in order to

A

Prevent sparking across the gap between the points

B

Cause more rapid break of the primary current, giving a higher voltage in the secondary circuit

C

Both (A) and (B)

D

None of the above

At series resonance, voltage across L is ___________ voltage across C

A

Equal to but opposite in phase to

B

Equal to but in phase with

C

Greater than but in phase with

D

Less than but in phase with

Circuit breaker in a stock exchange works as -

A

a medium to spilt stocks

B

An obstacle to excessive change in share price

C

A policy for broker houses

D

A constraint to issue bonus shares

Circuit breaker in a stock exchange works as ----

A

A medium to split stocks

B

An obstacle to excessive change in share price

C

A policy for broker houses

D

A constrain to issue bonus shares

The use of high speed circuit breaker -

A

reduces the short circuit current

B

increase the short circuit current

C

improves system stability

D

decrease system stability

Circuit breaker is the team generally used in:

A

Stock Exchange

B

Commercial

C

Insurance Company

D

Leasing Company

The voltage appearing across the contacts after opening of the circuit breaker is called______voltage.

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