Hi friends, this is post about objectives of electrical engineering with emphasis on dc motor check out and comment...
1) If the speed of a dc motor increases with load torque, then it is a
A) series motor
B) permanent magnet
C) differentially compounded motor
D) cumulatively compounded motor
Ans:C
2) The speed of a 4-pole dc series motor at no load will be
A) zero
B) 3000 rpm
C) infinite
D) 1500 rpm
E) depending upon the applied voltage
Ans:C
3) When the torque of a dc series motor is trippled, the power approximately increases by
A) 33%
B) 50%
C) 75%
D) 150%
Ans:C
4) It is advisable to start a dc series motor with some load to
A) limit the flux
B) limit the current
C) limit the speed
D) avoid sparking
E) avoid demagnetization of field system
Ans:C
5) If the supply voltage to a dc shunt motor is increased by 15%, which of the following will reduce?
A) Full load current
B) Full load speed
C) starting torque
D) None of the above
Ans:A
6) A dc shunt motor may have rising speed torque characteristic due to
A) very high armature circuit resistance
B) very high field circuit resistance
C) very high demagnetizing armature reaction
D) very low demagnetizing armature reaction
Ans:C
7) DC shunt motors are used for driving
A) machine tools
B) lathes
C) centrifugal pumps
D) line shafts
E) blowers and fans
F) all of these
Ans:F
8) Running the machine at no load is inadvisable for
A) dc shunt motor
B) dc series motor
C) induction motor
D) synchronous motor
Ans:B
9) A dc series motor is used for an overhauling load. It can work stably if
A) the armature is shunted by a resistor
B) the field winding is reversed
C) a resistor is put in series with the machine
D) a divertor is put across the field
Ans:A
10) A dc series motor must not be started on no load because it would
A) not develop starting torque
B) fails to start without load
C) run at dangerously high speed
D) draw more current without producing sufficient torue
Ans:C
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1) If the speed of a dc motor increases with load torque, then it is a
A) series motor
B) permanent magnet
C) differentially compounded motor
D) cumulatively compounded motor
Ans:C
2) The speed of a 4-pole dc series motor at no load will be
A) zero
B) 3000 rpm
C) infinite
D) 1500 rpm
E) depending upon the applied voltage
Ans:C
3) When the torque of a dc series motor is trippled, the power approximately increases by
A) 33%
B) 50%
C) 75%
D) 150%
Ans:C
4) It is advisable to start a dc series motor with some load to
A) limit the flux
B) limit the current
C) limit the speed
D) avoid sparking
E) avoid demagnetization of field system
Ans:C
5) If the supply voltage to a dc shunt motor is increased by 15%, which of the following will reduce?
A) Full load current
B) Full load speed
C) starting torque
D) None of the above
Ans:A
6) A dc shunt motor may have rising speed torque characteristic due to
A) very high armature circuit resistance
B) very high field circuit resistance
C) very high demagnetizing armature reaction
D) very low demagnetizing armature reaction
Ans:C
7) DC shunt motors are used for driving
A) machine tools
B) lathes
C) centrifugal pumps
D) line shafts
E) blowers and fans
F) all of these
Ans:F
8) Running the machine at no load is inadvisable for
A) dc shunt motor
B) dc series motor
C) induction motor
D) synchronous motor
Ans:B
9) A dc series motor is used for an overhauling load. It can work stably if
A) the armature is shunted by a resistor
B) the field winding is reversed
C) a resistor is put in series with the machine
D) a divertor is put across the field
Ans:A
10) A dc series motor must not be started on no load because it would
A) not develop starting torque
B) fails to start without load
C) run at dangerously high speed
D) draw more current without producing sufficient torue
Ans:C
If you like my post share it with your friends and subscribe for latest updates...
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