Question 1

The cylindrical windings using circular conductors are used for current rating of

Accepted Answer

A) upto 20 A 
B) upto 40 A 
C) upto 60 A 
D) upto 80 A 
A) upto 20 A 
B) upto 40 A 
C) upto 60 A 
D) upto 80 A D

Question 2

The weight of copper of both armature and field windings decreases with _____ in number of poles.

Accepted Answer

A) increase 
B) decrease 
C) either of the above 
D) none of the above 
A) increase 
B) decrease 
C) either of the above 
D) none of the above A

Question 3

The surge phenomenon is particularly important in case of

Accepted Answer

A) low voltage transformers 
B) medium voltage transformers 
C) high voltage transformers 
D) any of the above 
A) low voltage transformers 
B) medium voltage transformers 
C) high voltage transformers 
D) any of the above C

Question 4

In D.C. machines, the ____ in field mmf results in increase in size and cost of machines.

Accepted Answer

A) increase 
B) decrease 
C) either of the above 
D) none of the above 
A) increase 
B) decrease 
C) either of the above 
D) none of the above

Question 5

In a D.C. machine the number of brush arms is _____ the number of poles.

Accepted Answer

A) less than 
B) equal to 
C) greater than 
D) none of the above 
A) less than 
B) equal to 
C) greater than 
D) none of the above

Question 6

D.C. servomotors are used in

Accepted Answer

A) purely D.C. control systems 
B) purely AC. control systems 
C) both D.C. and AC. control systems 
D) none of the above 
A) purely D.C. control systems 
B) purely AC. control systems 
C) both D.C. and AC. control systems 
D) none of the above

Question 7

In D.C. machines the number of slots per pole usually lies

Accepted Answer

A) between 2 to 4 
B) between 6 to 8 
C) between 9 to 16 
D) between 20 to 30 
A) between 2 to 4 
B) between 6 to 8 
C) between 9 to 16 
D) between 20 to 30

Question 8

In D.C. machines the width of the duct is usually

Accepted Answer

A) 4 mm 
B) 6 mm 
C) 8 mm 
D) 10 mm 
A) 4 mm 
B) 6 mm 
C) 8 mm 
D) 10 mm

Question 9

In a D.C. machine, the value of peripheral speed should not, normally, exceed

Accepted Answer

A) 10 m/s 
B) 20 m/s 
C) 30 m/s 
D) 40 m/s 
A) 10 m/s 
B) 20 m/s 
C) 30 m/s 
D) 40 m/s

Question 10

Which of the following in an application of D.C. motors?

Accepted Answer

A) Traction 
B) Drives for process industry 
C) Battery driven vehicles 
D) All of the above 
A) Traction 
B) Drives for process industry 
C) Battery driven vehicles 
D) All of the above

Question 11

In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made

Accepted Answer

A) equal to that of armature mmf 
B) less in comparison with the arma¬ture mmf 
C) large in comparison with the arma-ture mmf 
D) none of the above 
A) equal to that of armature mmf 
B) less in comparison with the arma¬ture mmf 
C) large in comparison with the arma-ture mmf 
D) none of the above

Question 12

______ brushes are fragile and cause excessive wear of commutator,

Accepted Answer

A) Natural graphite 
B) Hard carbon 
C) Electro graphitic 
D) Metal graphite 
A) Natural graphite 
B) Hard carbon 
C) Electro graphitic 
D) Metal graphite

Question 13

In a D.C. machine the current per brush arm should not be more than

Accepted Answer

A) 100 A 
B) 200 A 
C) 300 A 
D) 400 A 
A) 100 A 
B) 200 A 
C) 300 A 
D) 400 A

Question 14

Which of the following methods may be adopted to reduce the effects of armature reaction ?

Accepted Answer

A) Increase in length of air gap at pole tips 
B) Increasing reluctance of pole tips 
C) Compensating windings 
D) All of the above 
A) Increase in length of air gap at pole tips 
B) Increasing reluctance of pole tips 
C) Compensating windings 
D) All of the above

Question 15

The insulation between windings and grounded core and the insulation between the windings of the same phase is called

Accepted Answer

A) minor insulation 
B) major insulation 
C) either of the above 
D) none of the above 
A) minor insulation 
B) major insulation 
C) either of the above 
D) none of the above

Question 16

D.C. machines designed with a large value of air gap length have

Accepted Answer

A) worst, ventilation 
B) poor ventilation 
C) better ventilation 
D) none of the above 
A) worst, ventilation 
B) poor ventilation 
C) better ventilation 
D) none of the above

Question 17

The operation of a D.C. machine with large air gap lengths is comparatively

Accepted Answer

A) quiet 
B) noisy 
C) either of the above 
D) none of the above 
A) quiet 
B) noisy 
C) either of the above 
D) none of the above

Question 18

In D.C. machines the usual limit of slot pitch is

Accepted Answer

A) between 5 to 10 mm 
B) between 10 to 15 mm 
C) between 15 to 20 mm 
D) between 25 to 35 mm 
A) between 5 to 10 mm 
B) between 10 to 15 mm 
C) between 15 to 20 mm 
D) between 25 to 35 mm

Question 19

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is

Accepted Answer

A) 1 + 0.2 kVmm 
B) 2 + 0.5 kVmm 
C) 4 + 0.7 kV mm 
D) 5 + 0.9 kV mm 
A) 1 + 0.2 kVmm 
B) 2 + 0.5 kVmm 
C) 4 + 0.7 kV mm 
D) 5 + 0.9 kV mm

Question 20

The stator of a D.C. machine comprises of

Accepted Answer

A) main poles 
B) interpoles 
C) frame 
D) all of the above 
A) main poles 
B) interpoles 
C) frame 
D) all of the above

The cylindrical windings using circular conductors are used for current rating of

The weight of copper of both armature and field windings decreases with _____ in number of poles.

The surge phenomenon is particularly important in case of

In D.C. machines, the ____ in field mmf results in increase in size and cost of machines.

In a D.C. machine the number of brush arms is _____ the number of poles.

D.C. servomotors are used in

In D.C. machines the number of slots per pole usually lies

In D.C. machines the width of the duct is usually

In a D.C. machine, the value of peripheral speed should not, normally, exceed

Which of the following in an application of D.C. motors?

In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made

______ brushes are fragile and cause excessive wear of commutator,

In a D.C. machine the current per brush arm should not be more than

Which of the following methods may be adopted to reduce the effects of armature reaction ?

The insulation between windings and grounded core and the insulation between the windings of the same phase is called

D.C. machines designed with a large value of air gap length have

The operation of a D.C. machine with large air gap lengths is comparatively

In D.C. machines the usual limit of slot pitch is

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is

The stator of a D.C. machine comprises of

Design Considerations and Materials for Electrical Machines

Cooling and Electromagnets for Machines

Transformer Design and Electromagnets

Filters

Exam 4: Design and Operation of DC Machines

The cylindrical windings using circular conductors are used for current rating of

The weight of copper of both armature and field windings decreases with _____ in number of poles.

The surge phenomenon is particularly important in case of

In D.C. machines, the ____ in field mmf results in increase in size and cost of machines.

In a D.C. machine the number of brush arms is _____ the number of poles.

D.C. servomotors are used in

In D.C. machines the number of slots per pole usually lies

In D.C. machines the width of the duct is usually

In a D.C. machine, the value of peripheral speed should not, normally, exceed

Which of the following in an application of D.C. motors?

In D.C. machines, ir order to prevent excessive distortion of field form by the armature reaction, the field mmf must be made

______ brushes are fragile and cause excessive wear of commutator,

In a D.C. machine the current per brush arm should not be more than

Which of the following methods may be adopted to reduce the effects of armature reaction ?

The insulation between windings and grounded core and the insulation between the windings of the same phase is called

D.C. machines designed with a large value of air gap length have

The operation of a D.C. machine with large air gap lengths is comparatively

In D.C. machines the usual limit of slot pitch is

A practical formula for determining the thickness of insulation between low voltage and high voltage windings is

The stator of a D.C. machine comprises of

Design Considerations and Materials for Electrical Machines

Cooling and Electromagnets for Machines

Transformer Design and Electromagnets

Filters