Electrical Machine - I (3140913) MCQs

MCQs of DC Machines

Showing 121 to 130 out of 167 Questions
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121.
Which of the following DC Motor uses a 4-point starter?
(a) DC shunt motor with field weakening control
(b) DC series motor
(c) DC compound motor
(d) DC shunt motor with armature resistance
Answer:

Option (d)

122.
High inrush of current during a starting of DC motor can efficiently be restricted to a safer value by increasing the _________________ resistance.
(a) armature circuit
(b) shunt field
(c) both A and B
(d) none of the above
Answer:

Option (a)

123.
In a separately excited DC Motor if field current is increased, it will
(a) Increase speed
(b) Reduce armature heating
(c) Reduce starting torque
(d) Increase acceleration duration
Answer:

Option (b)

124.
A DC series motor is running with a diverter connected across its field winding. If the diverter resistance is reduced then the speed of the motor will
(a) increase
(b) decrease
(c) remain unaltered
(d) become excessively high
Answer:

Option (b)

125.
In speed control of DC shunt motor by varying field flux, what may be the value of field regulator?
(a) 0.1 ohm
(b) 1 ohm
(c) 10 ohm
(d) 100 ohm
Answer:

Option (d)

126.
DC Shunt Motor has a disadvantage(s) of
(a) constant speed
(b) less expensive
(c) not suitable for rapidly changing loads
(d) none of the above
Answer:

Option (c)

127.
Ward-Leonard system for controlling the speed of a DC motor is used where
(a) The accuracy in speed control is required
(b) The speed in both the direction is required
(c) Very fine speed control over the whole range from zero to normal speed is required
(d) All of the above
Answer:

Option (d)

128.
The speed of a cumulatively compound DC motor can be controlled by varying
(a) Armature resistance control
(b) Shunt field resistance control
(c) Armature voltage control
(d) Any of the above
Answer:

Option (d)

129.
The type of DC motor generally used for shears and punches is
(a) Series motor
(b) Shunt motor
(c) Cumulative compound motor
(d) Differential compound motor
Answer:

Option (c)

130.
A 220 V DC machine has an armature resistance 1 Ω. If the full load current is 20 A, the difference of induced voltage between generator and motor is
(a) 0 V
(b) 20 V
(c) 40 V
(d) 80 V
Answer:

Option (c)

Showing 121 to 130 out of 167 Questions
10 11 12 13 14 15