Q.1
Which of the following DC motor has the poorest speed control?
  • a) Differentially compounded motor
  • b) Cumulatively compounded motor
  • c) Shunt motor
  • d) Series motor
Q.2
In variable speed motor ____________
  • a) Stronger commutating field is needed at low speed than at high speed
  • b) Weaker commutating field is needed at low speed than at high speed
  • c) Same commutating field is needed at low speed and at high speed
  • d) Cannot be determined
Q.3
The speed of a motor falls fromrpm at no-load torpm at rated load. The speed regulation of the motor is ____________
  • a) 12.36%
  • b) 14.28%
  • c) 16.77%
  • d) 18.84%
Q.4
Which of the following is not the method of speed control in DC series motor?
  • a) Diverter
  • b) Tapped-field control
  • c) Variable resistance in series with armature
  • d) Series- parallel control
Q.5
For speed reversal, field control method is suitable.
  • a) True
  • b) False
Q.6
For large motors what is the ratio of compensating winding is required for increasing the speed of the motor?
  • a) 2:1
  • b) 4:1
  • c) 6:1
  • d) 8:1
Q.7
In diverter resistor field control method of DC series motor, variable resistor is added ________
  • a) In parallel with field
  • b) In series with field
  • c) In parallel with armature
  • d) In parallel with load
Q.8
Why it is advisable to use inductively wound diverter resistor?
  • a) To make speed control on more range
  • b) For long-life of machine
  • c) Cost efficient
  • d) To avoid oscillations in speed
Q.9
For higher diverter resistance, speed-torque characteristic will lie ____________
  • a) Above speed-torque characteristic of lower resistance
  • b) Below speed-torque characteristic of lower resistance
  • c) On the speed-torque characteristic of lower resistance
  • d) Cannot say
Q.10
In tapped field control method ____________
  • a) A variable resistor is connected in parallel
  • b) A variable resistor is connected in series
  • c) Field winding is made with more out pins
  • d) Another field winding is added with the previous one
Q.11
Which of the following method will not give many speed values for a DC series motor?
  • a) Diverter
  • b) Series-parallel
  • c) Field tapped
  • d) All field control methods will give many speed values
Q.12
In series-parallel speed control method ______________
  • a) Speed given by parallel connection is more
  • b) Speed given by series connection is more
  • c) Both speeds can be equal
  • d) Will depend on other parameters
Q.13
Where diverters are used?
  • a) In shunt motors
  • b) In series motors
  • c) In both motors
  • d) All other motors except shunt and series motors
Q.14
What will happen to the speed of a series motor if the temperature of armature resistance is increased?
  • a) Not change
  • b) Decreases
  • c) Increases
  • d) Cannot be determined
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