Switchgear and Protection MCQs Part 7

Switchgear and Protection MCQs Part 7

In bulk oil circuit breaker, the oil actually used for arc extinction is about

In bulk oil circuit breaker, the oil actually used for arc extinction is about:

1. 10% of total
2. 40% of total
3. 80% of total
4. 90% of total

Correct answer: 1. 10% of total

The relay operating coil is supplied through

The relay operating coil is supplied through:

1. Power transformer
2. Current transformer
3. Fuse
4. None of these

Correct answer: 2. Current transformer

A fuse should have

A fuse should have:

1. High conductivity
2. Low melting point
3. Economical
4. All of these

Correct answer: 4. All of these

While using air-blast circuit breaker current chopping is often observed when

While using air-blast circuit breaker current chopping is often observed when:

1. A heavy load is switched off
2. A long overhead transmission line is switched off
3. A transformer on no-load is switched off
4. None of these

Correct answer: 3. A transformer on no-load is switched off

Arc interruption takes place in oil circuit breaker when

Arc interruption takes place in oil circuit breaker when:

1. Voltage goes through zero
2. Current goes through zero
3. Contacts move apparat
4. None of these

Correct answer: 2. Current goes through zero