Electrical Machine - I (3140913) MCQs

MCQs of DC Machines

Showing 111 to 120 out of 167 Questions
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111.
In which of the following DC Motor the ratio of starting torque to full load torque is minimum?
(a) Shunt motor
(b) Series motor
(c) Differential compound motor
(d) Cumulative compound motor
Answer:

Option (c)

112.
The main disadvantage(s) of the ward-Leonard system is/are
(a) high initial cost
(b) high maintenance cost
(c) poor overall efficiency
(d) all of the above
Answer:

Option (d)

113.
Ward Leonard control provides speed control
(a) in both direction
(b) in one direction only
(c) below rated speed
(d) above rated speed
Answer:

Option (a)

114.
In the case of DC Shunt Motor, the speed will____ if the voltage increases, neglecting armature saturation.
(a) increase
(b) decrease
(c) remain the same
(d) be unpredictable
Answer:

Option (c)

115.
Which of the following DC Motor requires 3 point starter?
(a) Shunt motor
(b) Series motor
(c) Shunt motor as well as compound motors
(d) Shunt, compound and series motor
Answer:

Option (c)

116.
For starting a DC motor a starter is required because
(a) it limits the starting current
(b) It starts the motor
(c) it limits the speed of the motor
(d) None of the above
Answer:

Option (a)

117.
If the handle of a three point starter goes to back to OFF position, it may be due to
(a) overload
(b) high filed circuit resistance
(c) zero or very low voltage supply
(d) all of these
Answer:

Option (d)

118.
If the no-voltage release in a DC motor starter fails to operate on the failure of supply, on the resumption of supply the motor will
(a) develop very low starting torque
(b) start automatically without trouble
(c) get damaged
(d) not start automatically
Answer:

Option (c)

119.
In a DC Motor 3 point starter is used to
(a) provide protection against Low-Voltage
(b) provide overload protection
(c) limit the starting current to a safer value
(d) all of the above
Answer:

Option (d)

120.
If the starter is not used with large DC motor for starting, it will
(a) damage the armature and commutator
(b) draw a starting current many times its rated full load current
(c) provide an excessive voltage drop in line
(d) all of the above
Answer:

Option (d)

Showing 111 to 120 out of 167 Questions
9 10 11 12 13 14