Electrical Machine - I (3140913) MCQs

MCQs of DC Machines

Showing 91 to 100 out of 167 Questions
7 8 9 10 11 12
91.
A large series motor is never started without some mechanical load on it because otherwise, it will
(a) produce sparking at brushes
(b) open fuse or circuit breaker
(c) draw too much current
(d) develop excessive speed and damage itself
Answer:

Option (d)

92.
Which of the following winding is connected in series with armature winding of DC machine?
(a) Auxiliary winding
(b) Compensating winding
(c) Both Compensating and Commutating pole winding
(d) Commutating pole winding
Answer:

Option (c)

93.
The direction of rotation of DC motor is reversed by
(a) Reversing supply connection
(b) Adding resistance to the field circuit
(c) Interchanging armature and field connection
(d) Reversing armature connection or field connection
Answer:

Option (d)

94.
With the increase in the speed of a DC motor
(a) back emf increases but line current falls
(b) back emf falls and line current increases
(c) both back emf as well as line current increase
(d) both back emf as well as line current fall
Answer:

Option (a)

95.
If the back emf in DC motor vanishes suddenly the motor will
(a) burn
(b) run at very high speed
(c) run at a very low speed.
(d) start haunting
Answer:

Option (a)

96.
The speed of a DC motor is
(a) directly proportional to flux and inversely proportional to back emf
(b) directly proportional to both back emf and flux
(c) inversely proportional to both back emf and flux
(d) directly proportional to back emf and inversely proportional flux
Answer:

Option (d)

97.
The direction of rotation of conductor of a DC motor can be determined by
(a) Ampere law
(b) Fleming's left-hand rule
(c) Fleming's right-hand rule
(d) Lenz's law
Answer:

Option (b)

98.
If the temperature of armature resistance is increased, the speed of a series motor would
(a) not change
(b) decrease
(c) increase
(d) None of above
Answer:

Option (b)

99.
For the same HP rating and full load speed which of the following motor has poor starting torque?
(a) Series
(b) Shunt
(c) Cumulative compound
(d) Differently compounded
Answer:

Option (d)

100.
Which of the DC Motor uses flywheel?
(a) Shunt motor
(b) Cumulatively compound motor
(c) Differently compared motor
(d) Series motor
Answer:

Option (b)

Showing 91 to 100 out of 167 Questions
7 8 9 10 11 12