Question 1

Air blast circuit breaker is used for

Accepted Answer

A) over currents 
B) short duty 
C) intermittant duty 
D) repeated duty 
A) over currents 
B) short duty 
C) intermittant duty 
D) repeated duty D

Question 2

Circuit breakers usually operate under

Accepted Answer

A) transient state of short-circuit current 
B) sub-transient state of short-circuit current 
C) steady state of short-circuit current 
D) after D.C. component has ceased 
A) transient state of short-circuit current 
B) sub-transient state of short-circuit current 
C) steady state of short-circuit current 
D) after D.C. component has ceased A

Question 3

Arc in a circuit behaves as

Accepted Answer

A) a capackive reactance 
B) an inductive reactance 
C) a resistance increasing with voltage rise across the arc 
D) a resistance decreasing with voltage rise across the arc 
A) a capackive reactance 
B) an inductive reactance 
C) a resistance increasing with voltage rise across the arc 
D) a resistance decreasing with voltage rise across the arc D

Question 4

The arcing contacts in a circuit breaker are made of

Accepted Answer

A) copper tungsten alloy 
B) porcelain 
C) electrolytic copper 
D) aluminium alloy 
A) copper tungsten alloy 
B) porcelain 
C) electrolytic copper 
D) aluminium alloy

Question 5

The current zero interruption, in oil and air blast circuit breakers, is achieved by

Accepted Answer

A) lengthening of the gap 
B) cooling and blast effect 
C) both (a) and (b) 
D) deionizing the oil with forced air 
A) lengthening of the gap 
B) cooling and blast effect 
C) both (a) and (b) 
D) deionizing the oil with forced air

Question 6

Thermal circuit breaker has

Accepted Answer

A) delayed trip action 
B) instantaneous trip action 
C) both of the above 
D) none of the above 
A) delayed trip action 
B) instantaneous trip action 
C) both of the above 
D) none of the above

Question 7

A differential relay measures the vector difference between

Accepted Answer

A) two currents 
B) two voltages 
C) two or more similar electrical quantities 
D) none of the above 
A) two currents 
B) two voltages 
C) two or more similar electrical quantities 
D) none of the above

Question 8

Thermal overload relays are used to protect the motor against over current due to

Accepted Answer

A) short-circuits 
B) heavy loads 
C) grounds 
D) all of the above 
A) short-circuits 
B) heavy loads 
C) grounds 
D) all of the above

Question 9

Fault diverters are basically

Accepted Answer

A) fuses 
B) relays 
C) fast switches 
D) circuit breakers 
A) fuses 
B) relays 
C) fast switches 
D) circuit breakers

Question 10

Magnetic circuit breaker has ______ trip action.

Accepted Answer

A) delayed 
B) instantaneous 
C) both of the above 
D) none of the above 
A) delayed 
B) instantaneous 
C) both of the above 
D) none of the above

Question 11

An efficient and a well designed protective relaying should have

Accepted Answer

A) good selectivity and reliability 
B) economy and simplicity 
C) high speed and selectivity 
D) all of the above 
A) good selectivity and reliability 
B) economy and simplicity 
C) high speed and selectivity 
D) all of the above

Question 12

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

Accepted Answer

A) have low contact resistance 
B) be clean and smooth 
C) be of sufficient size and proper shape 
D) have all above properties 
A) have low contact resistance 
B) be clean and smooth 
C) be of sufficient size and proper shape 
D) have all above properties

Question 13

SF6 gas

Accepted Answer

A) is yellow in colour 
B) is lighter than air 
C) is nontoxic 
D) has pungent small 
A) is yellow in colour 
B) is lighter than air 
C) is nontoxic 
D) has pungent small

Question 14

On which of the following routine tests are conducted?

Accepted Answer

A) Oil circuit breakers 
B) Air blast circuit breakers 
C) Minimum oil circuit breakers 
D) All of the above 
A) Oil circuit breakers 
B) Air blast circuit breakers 
C) Minimum oil circuit breakers 
D) All of the above

Question 15

Overload relays are of…… type.

Accepted Answer

A) induction 
B) solid state 
C) thermal 
D) all above 
A) induction 
B) solid state 
C) thermal 
D) all above

Question 16

Which of the following medium is employed for extinction of arc in air circuit breaker ?

Accepted Answer

A) Water 
B) Oil 
C) Air 
D) SF6 
A) Water 
B) Oil 
C) Air 
D) SF6

Question 17

With which of the following, a circuit breaker must be equipped for remote operation ?

Accepted Answer

A) Inverse time trip 
B) Time-delay trip 
C) Shunt trip 
D) None of the above 
A) Inverse time trip 
B) Time-delay trip 
C) Shunt trip 
D) None of the above

Question 18

A thermal protection switch can protect against

Accepted Answer

A) short-circuit 
B) temperature 
C) overload 
D) over voltage 
A) short-circuit 
B) temperature 
C) overload 
D) over voltage

Question 19

Relays can be designed to respond to changes in

Accepted Answer

A) resistance, reactance or impedance 
B) voltage and current 
C) light intensity 
D) all above 
A) resistance, reactance or impedance 
B) voltage and current 
C) light intensity 
D) all above

Question 20

The relay operating speed depends upon

Accepted Answer

A) the spring tension 
B) the rate of flux built up 
C) armature core air gap 
D) all of the above 
A) the spring tension 
B) the rate of flux built up 
C) armature core air gap 
D) all of the above

Air blast circuit breaker is used for

Circuit breakers usually operate under

Arc in a circuit behaves as

The arcing contacts in a circuit breaker are made of

The current zero interruption, in oil and air blast circuit breakers, is achieved by

Thermal circuit breaker has

A differential relay measures the vector difference between

Thermal overload relays are used to protect the motor against over current due to

Fault diverters are basically

Magnetic circuit breaker has ______ trip action.

An efficient and a well designed protective relaying should have

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

SF6 gas

On which of the following routine tests are conducted?

Overload relays are of…… type.

Which of the following medium is employed for extinction of arc in air circuit breaker ?

With which of the following, a circuit breaker must be equipped for remote operation ?

A thermal protection switch can protect against

Relays can be designed to respond to changes in

The relay operating speed depends upon

Electrical Protection and Transmission Systems

Electrical Substation Equipment and Protection Systems

Electrical Protection and Circuit Breakers

Electrical Protection and Switchgear Systems

Electrical Protection and Circuit Breakers

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Exam 1: Electrical Components and Protective Relays

Air blast circuit breaker is used for

Circuit breakers usually operate under

Arc in a circuit behaves as

The arcing contacts in a circuit breaker are made of

The current zero interruption, in oil and air blast circuit breakers, is achieved by

Thermal circuit breaker has

A differential relay measures the vector difference between

Thermal overload relays are used to protect the motor against over current due to

Fault diverters are basically

Magnetic circuit breaker has ______ trip action.

An efficient and a well designed protective relaying should have

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

SF6 gas

On which of the following routine tests are conducted?

Overload relays are of…… type.

Which of the following medium is employed for extinction of arc in air circuit breaker ?

With which of the following, a circuit breaker must be equipped for remote operation ?

A thermal protection switch can protect against

Relays can be designed to respond to changes in

The relay operating speed depends upon

Electrical Protection and Transmission Systems

Electrical Substation Equipment and Protection Systems

Electrical Protection and Circuit Breakers

Electrical Protection and Switchgear Systems

Electrical Protection and Circuit Breakers

Filters