1-Which of the following load normally need starting torque more than the rated torque? (a) Conveyors (b) Blowers © Centrifugal pump (d) Air compressor 2-The efficiency of the DC motor at maximum power is |(a) 90% (b) 100% © Around 80% (d) Less than 50% 3-in which of the following applications DC series motor is used?
1-Which of the following load normally need starting torque more than the rated torque? (a) Conveyors (b) Blowers © Centrifugal pump (d) Air compressor 2-The efficiency of the DC motor at maximum power is |(a) 90% (b) 100% © Around 80% (d) Less than 50% 3-in which of the following applications DC series motor is used?
Introductory Circuit Analysis (13th Edition)
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ISBN:9780133923605
Author:Robert L. Boylestad
Publisher:Robert L. Boylestad
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Question
![1-Which of the following load normally need starting torque more than the rated torque?
© Centrifugal pump
(a) Conveyors
2-The efficiency of the DC motor at maximum power is
(b) Blowers
(d) Air compressor
(a) 90%
(b) 100%
© Around 80%
(d) Less than 50%
3-in which of the following applications DC series motor is used?
(a) Centrifugal Pump
(b) Motor Operation in DC and AC
© Water pump drive
(d) Starter for car
4-Which DC motor has the least percentage increase in Input current for the same percentage
increase in torque?
(a)Separately excited motor
(b)Series motor
© Shunt motor ( d)Compound motor
5-Counter EMF of the DC motor is
(b)More than the applied voltage
(a) Less than the applied voltage
© Equal to the applied voltage
6-Which DC motor is used for the conveyor?
(d)None of the above
(a)Series motor (b)Cumulative compound motor(c) Differentially compound motor
(d)Shunt
motor
7-Which D.C motor is preferred for machine tools?
(a) Series motor
(b)Cumulative compound motor (
c) Differentially compound motor
(d)Shunt motor
8-When the speed of D.C motor is increased
(a)Back E.M.F increases and current drawn decreases (b) Back E.M.F decreases and current drawn
increases
© Back E.M.F and current drawn both increases (d)Back E.M.F and current drawn both decreases
9-A 240v de shunt motor with an armature resistance of 0.5 has a full load current of 40A.
Find out the ratio of the stalling torque to the full load torque when a resistance of 1 ohm is
connected in series with the armature
(a)12
(b) 6
© 4
(d)10
10-A DC Motor is driving a constant load torque having armature resistance of 0.15 2 and
armature current of 0.25 A having connected to a voltage of 230 V. Now a resistance of 1 ohm
is added into the armature circuit. The ratio of their speed will be
(a)0.25
(b)1.24
©0.62
(d)0.72
11-220 V, 15 kW, 1000 RPM shunt Motor with an armature resistance of 0.252, has a rated
line current of 68 A and a rated field current of 2.2 A. The change in field flux required to
obtain a speed of 1600 RPM while drawing a line current of 52.8 A and a field current of 1.8 A
is
(a)18.18% Increase
(b)18. 18% decrease
©36.36 % increase
(d)36. 36 % decrease](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F3728370c-f7f9-49d3-bcff-1f582c801f3f%2F35a56673-3523-4bdd-a4fc-af9681afd223%2F6odptnb_processed.jpeg&w=3840&q=75)
Transcribed Image Text:1-Which of the following load normally need starting torque more than the rated torque?
© Centrifugal pump
(a) Conveyors
2-The efficiency of the DC motor at maximum power is
(b) Blowers
(d) Air compressor
(a) 90%
(b) 100%
© Around 80%
(d) Less than 50%
3-in which of the following applications DC series motor is used?
(a) Centrifugal Pump
(b) Motor Operation in DC and AC
© Water pump drive
(d) Starter for car
4-Which DC motor has the least percentage increase in Input current for the same percentage
increase in torque?
(a)Separately excited motor
(b)Series motor
© Shunt motor ( d)Compound motor
5-Counter EMF of the DC motor is
(b)More than the applied voltage
(a) Less than the applied voltage
© Equal to the applied voltage
6-Which DC motor is used for the conveyor?
(d)None of the above
(a)Series motor (b)Cumulative compound motor(c) Differentially compound motor
(d)Shunt
motor
7-Which D.C motor is preferred for machine tools?
(a) Series motor
(b)Cumulative compound motor (
c) Differentially compound motor
(d)Shunt motor
8-When the speed of D.C motor is increased
(a)Back E.M.F increases and current drawn decreases (b) Back E.M.F decreases and current drawn
increases
© Back E.M.F and current drawn both increases (d)Back E.M.F and current drawn both decreases
9-A 240v de shunt motor with an armature resistance of 0.5 has a full load current of 40A.
Find out the ratio of the stalling torque to the full load torque when a resistance of 1 ohm is
connected in series with the armature
(a)12
(b) 6
© 4
(d)10
10-A DC Motor is driving a constant load torque having armature resistance of 0.15 2 and
armature current of 0.25 A having connected to a voltage of 230 V. Now a resistance of 1 ohm
is added into the armature circuit. The ratio of their speed will be
(a)0.25
(b)1.24
©0.62
(d)0.72
11-220 V, 15 kW, 1000 RPM shunt Motor with an armature resistance of 0.252, has a rated
line current of 68 A and a rated field current of 2.2 A. The change in field flux required to
obtain a speed of 1600 RPM while drawing a line current of 52.8 A and a field current of 1.8 A
is
(a)18.18% Increase
(b)18. 18% decrease
©36.36 % increase
(d)36. 36 % decrease
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