Question 1

Flashing the field of D.C. generator means

Accepted Answer

A) neutralising residual magnetism 
B) creating residual magnetism by a D.C. source 
C) making the magnetic losses of forces parallel 
D) increasing flux density by adding extra turns of windings on poles 
A) neutralising residual magnetism 
B) creating residual magnetism by a D.C. source 
C) making the magnetic losses of forces parallel 
D) increasing flux density by adding extra turns of windings on poles B

Question 2

To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead soas to bring them

Accepted Answer

A) just ahead of magnetic neutral axis 
B) in magnetic neutral axis 
C) just behind the magnetic neutral axis 
D) none 
A) just ahead of magnetic neutral axis 
B) in magnetic neutral axis 
C) just behind the magnetic neutral axis 
D) none A

Question 3

Open circuited armature coil of a D.C. machine is

Accepted Answer

A) identified by the scarring of the commutator segment to which open circuited coil is connected 
B) indicated by a spark completely around the commutator 
C) both (a) and (b) 
D) none of the above 
A) identified by the scarring of the commutator segment to which open circuited coil is connected 
B) indicated by a spark completely around the commutator 
C) both (a) and (b) 
D) none of the above C

Question 4

A cumulatively compounded long shunt generator when operating as a motor would be

Accepted Answer

A) cumulatively compounded long shunt 
B) differentially compounded long shunt 
C) cumulatively compounded short shunt 
D) differentially compounded short shunt 
A) cumulatively compounded long shunt 
B) differentially compounded long shunt 
C) cumulatively compounded short shunt 
D) differentially compounded short shunt

Question 5

For the parallel operation of two or more D.C. compound generators, we should ensure that

Accepted Answer

A) voltage of the incoming generator should be same as that of bus bar 
B) polarity of incoming generator should be same as that of bus bar 
C) all the series fields should be run in parallel by means of equilizer connection 
D) series fields of all generators should be either on positive side or negative side of the armature 
A) voltage of the incoming generator should be same as that of bus bar 
B) polarity of incoming generator should be same as that of bus bar 
C) all the series fields should be run in parallel by means of equilizer connection 
D) series fields of all generators should be either on positive side or negative side of the armature

Question 6

D.C. series generator is used

Accepted Answer

A) to supply traction load 
B) to supply industrial load at constant voltage 
C) voltage at the toad end of the feeder 
D) for none of the above purpose 
A) to supply traction load 
B) to supply industrial load at constant voltage 
C) voltage at the toad end of the feeder 
D) for none of the above purpose

Question 7

To avoid formation of grooves in the commutator of a D.C. machine

Accepted Answer

A) the brushes of opposite polarity should track each other 
B) the brushes of same polarity should track each other 
C) brush position has no effect on the commutator grooving 
A) the brushes of opposite polarity should track each other 
B) the brushes of same polarity should track each other 
C) brush position has no effect on the commutator grooving

Question 8

Permeance is the reciprocal of

Accepted Answer

A) flux density 
B) reluctance 
C) ampere-turns 
D) resis tance 
A) flux density 
B) reluctance 
C) ampere-turns 
D) resis tance

Question 9

In a D.C. generator the critical resistance refers to the resistance of

Accepted Answer

A) brushes 
B) field 
C) armature 
D) load 
A) brushes 
B) field 
C) armature 
D) load

Question 10

In D.C. generators the polarity of the interpoles

Accepted Answer

A) is the same as that of the main pole ahead 
B) is the same as that of the immediately preceding pole 
C) is opposite to that of the main pole ahead 
D) is neutral as these poles do not play part in generating e.m.f. 
A) is the same as that of the main pole ahead 
B) is the same as that of the immediately preceding pole 
C) is opposite to that of the main pole ahead 
D) is neutral as these poles do not play part in generating e.m.f.

Question 11

D.C. generator generally preferred for charging automobile batteries is

Accepted Answer

A) series generator 
B) shunt generator 
C) long shunt compound generator 
D) any of'the above 
A) series generator 
B) shunt generator 
C) long shunt compound generator 
D) any of'the above

Question 12

The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be

Accepted Answer

A) 640 V 
B) 620 V 
C) 600 V 
D) 580V 
A) 640 V 
B) 620 V 
C) 600 V 
D) 580V

Question 13

If a D.C. generator fails to build up the probable cause could not be

Accepted Answer

A) imperfect brush contact 
B) field resistance less than the critical resistance 
C) no residual magnetism in the generator 
D) faulty shunt connections tending to reduce the residual magnetism 
A) imperfect brush contact 
B) field resistance less than the critical resistance 
C) no residual magnetism in the generator 
D) faulty shunt connections tending to reduce the residual magnetism

Question 14

Following D.C. generator will be in a position to build up without any residual magnetism in the poles

Accepted Answer

A) series generator 
B) shunt generator 
C) compound generator 
D) self-excited generator 
A) series generator 
B) shunt generator 
C) compound generator 
D) self-excited generator

Question 15

In D.C. generators on no-load, the air gap flux distribution in space is

Accepted Answer

A) sinusoidal 
B) triangular 
C) pulsating 
D) flat topped 
A) sinusoidal 
B) triangular 
C) pulsating 
D) flat topped

Question 16

The following constitute short-circuit in the armature winding.

Accepted Answer

A) Insulation failure between two com-mutator bars 
B) Insulation failure between two turns of a coil 
C) Two of more turns of the same coil getting grounded 
D) All of the above 
A) Insulation failure between two com-mutator bars 
B) Insulation failure between two turns of a coil 
C) Two of more turns of the same coil getting grounded 
D) All of the above

Question 17

Armature coil is short circuited by brushes when it lies

Accepted Answer

A) along neutral axis 
B) along field axis 
C) in All of the above positions 
D) in none of the above positions 
A) along neutral axis 
B) along field axis 
C) in All of the above positions 
D) in none of the above positions

Question 18

The e.m.f. generated in a D.C. generator is directly proportional to

Accepted Answer

A) flux/pole 
B) speed of armature 
C) number of poles 
D) all of the above 
A) flux/pole 
B) speed of armature 
C) number of poles 
D) all of the above

Question 19

A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If thespeed increases to 1200 r.p.m., the generated e.m.f. will be nearly

Accepted Answer

A) 150 V 
B) 175 V 
C) 240 V 
D) 290V 
A) 150 V 
B) 175 V 
C) 240 V 
D) 290V

Question 20

The armature core of a D.C. generator is usually made of

Accepted Answer

A) silicon steel 
B) copper 
C) non-ferrous material 
D) cast-iron 
A) silicon steel 
B) copper 
C) non-ferrous material 
D) cast-iron

Flashing the field of D.C. generator means

To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead soas to bring them

Open circuited armature coil of a D.C. machine is

A cumulatively compounded long shunt generator when operating as a motor would be

For the parallel operation of two or more D.C. compound generators, we should ensure that

D.C. series generator is used

To avoid formation of grooves in the commutator of a D.C. machine

Permeance is the reciprocal of

In a D.C. generator the critical resistance refers to the resistance of

In D.C. generators the polarity of the interpoles

D.C. generator generally preferred for charging automobile batteries is

The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be

If a D.C. generator fails to build up the probable cause could not be

Following D.C. generator will be in a position to build up without any residual magnetism in the poles

In D.C. generators on no-load, the air gap flux distribution in space is

The following constitute short-circuit in the armature winding.

Armature coil is short circuited by brushes when it lies

The e.m.f. generated in a D.C. generator is directly proportional to

A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If thespeed increases to 1200 r.p.m., the generated e.m.f. will be nearly

The armature core of a D.C. generator is usually made of

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Exam 13: D.C Generator Operation and Construction

Flashing the field of D.C. generator means

To achieve sparkless commutation brushes of a D.C. generator are rockedm ahead soas to bring them

Open circuited armature coil of a D.C. machine is

A cumulatively compounded long shunt generator when operating as a motor would be

For the parallel operation of two or more D.C. compound generators, we should ensure that

D.C. series generator is used

To avoid formation of grooves in the commutator of a D.C. machine

Permeance is the reciprocal of

In a D.C. generator the critical resistance refers to the resistance of

In D.C. generators the polarity of the interpoles

D.C. generator generally preferred for charging automobile batteries is

The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be

If a D.C. generator fails to build up the probable cause could not be

Following D.C. generator will be in a position to build up without any residual magnetism in the poles

In D.C. generators on no-load, the air gap flux distribution in space is

The following constitute short-circuit in the armature winding.

Armature coil is short circuited by brushes when it lies

The e.m.f. generated in a D.C. generator is directly proportional to

A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If thespeed increases to 1200 r.p.m., the generated e.m.f. will be nearly

The armature core of a D.C. generator is usually made of

Transformer Fundamentals and Operation

Transformer Technology and Design

Transformer: Resistance, Oil, Relays, Harmonics, and Core Properties

Transformers: Efficiency, Design, and Testing

Transformers: Voltage Regulation, Efficiency, and Protection

Transformer and D.C Motor

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D.C Machine and Generator Laminations, Commutation, and Components

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D.C Generators

Direct Current Generators and Parallel Operation

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