Discuss
menu
search
person
Login
Register
search
edit
Ask a Question
Discuss
All Activity
Q&A
Questions
Hot!
Unanswered
Tags
Ask a Question
What is the RPM of a DC motor?
asked
Mar 15, 2018
by
anonymous
What is the RPM of a DC motor?
rpm
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
52
views
Please
log in
or
register
to add a comment.
Please
log in
or
register
to answer this question.
0
Answers
← Prev Question
Next Question →
Related questions
asked
May 3, 2018
by
anonymous
A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance
A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is
Last answer:
A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is 36 Ohm
dc
shunt
motor
running
current
armature
winding
resistance
thumb_up_alt
0
like
thumb_down_alt
0
dislike
169
views
1
answer
asked
Apr 29, 2018
by
anonymous
In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at
In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is :
Last answer:
In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is : 0.075
dc
series
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
70
views
1
answer
asked
Dec 16, 2017
by
anonymous
What are the speed control methods of dc motor?
What are the speed control methods of dc motor?
Last answer:
Field control of DC motor Armature control of DC motor
speed
control
methods
dc
motor
thumb_up_alt
3
like
thumb_down_alt
0
dislike
150
views
2
answers
asked
Apr 29, 2018
by
anonymous
The function of a brush and commutator arrangement in a dc motor is to
The function of a brush and commutator arrangement in a dc motor is to (1) produce unidirectional torque (2) produce unidirectional current in the armature (3) help in changing the direction of rotation of the armature (4) reduce sparking
Last answer:
The function of a brush and commutator arrangement in a dc motor is to produce unidirectional torque
function
brush
commutator
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
1.3k
views
1
answer
asked
May 8, 2018
by
anonymous
A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s.
A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be
Last answer:
A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be 474 V
dc
shunt
motor
rated
load
speed
thumb_up_alt
0
like
thumb_down_alt
0
dislike
220
views
1
answer
asked
Sep 18, 2018
by
anonymous
Describe the reason of using dc series motor for electric trains.
Describe the reason of using dc series motor for electric trains.
Last answer:
Electric trains require an inverse torque speed characteristics for proper operation. That is a higher torque is required at start (when speed is nil or low) and as the train picks up ... torque - speed characteristics of DC series motors match, these motors are suitable for electric trains
dc
series
motor
electric
trains
thumb_up_alt
0
like
thumb_down_alt
0
dislike
114
views
1
answer
asked
Sep 9, 2017
by
anonymous
is induction motor ac or dc?
Last answer:
Induction motor is a AC motor it is also known as asynchronous motor .
induction
motor
dc
ac
thumb_up_alt
1
like
thumb_down_alt
0
dislike
73
views
1
answer
asked
Aug 9, 2017
by
anonymous
Armature control of DC motor
Armature control of DC motor
Last answer:
Armature control of DC motor
armature
control
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
126
views
2
answers
asked
Aug 9, 2017
by
anonymous
Field control of DC motor
Field control of DC motor
Last answer:
Field control of DC motor
field
control
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
91
views
2
answers
asked
Aug 9, 2017
by
anonymous
Four Quadrant Operation Of DC Motor
Four Quadrant Operation Of DC Motor
Last answer:
Four Quadrant Operation Of DC Motor
four
quadrant
operation
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
207
views
1
answer
asked
Aug 9, 2017
by
anonymous
Separately Excited DC motor
Separately Excited DC motor
Last answer:
Separately Excited DC motor
separately
excited
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
294
views
2
answers
asked
Mar 15, 2018
by
anonymous
What is the back EMF of a dc motor?
What is the back EMF of a dc motor?
back
emf
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
2.5k
views
0
answers
asked
Mar 20, 2018
by
anonymous
What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?
Last answer:
The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.
back
emf
dc
motor
vanishes
suddenly
thumb_up_alt
0
like
thumb_down_alt
0
dislike
374
views
1
answer
asked
Mar 15, 2018
by
anonymous
What is the principle of DC motor?
What is the principle of DC motor?
principle
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
66
views
0
answers
asked
Aug 18, 2019
by
anonymous
What would happen if a DC motor was supplied with AC ?
What would happen if a DC motor was supplied with AC ?
Last answer:
With three phase induction motor, humming and not rotate, but if single phase universal motor like air blower, home mixture, motor run on constant speed..speed variation not possible...
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
91
views
2
answers
asked
Mar 15, 2018
by
anonymous
What are the advantages of DC series motor?
What are the advantages of DC series motor?
advantages
dc
series
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
80
views
0
answers
asked
Mar 20, 2018
by
anonymous
At the instant of starting when a D.C. motor is put on supply, it behaves like?
Last answer:
At the instant of starting when a D.C. motor is put on supply, it behaves like a low resistance circuit.
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
64
views
1
answer
asked
Mar 20, 2018
by
anonymous
As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent...
As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit?
Last answer:
As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit a resistance is connected in series with armature.
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
113
views
1
answer
asked
Mar 20, 2018
by
anonymous
In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to?
Last answer:
In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to 25% of the previous value.
dc
motor
series
thumb_up_alt
0
like
thumb_down_alt
0
dislike
140
views
1
answer
asked
Mar 20, 2018
by
anonymous
The speed of a D.C. series motor is?
Last answer:
The speed of a D.C. series motor is inversely proportional to the armature current.
speed
series
motor
dc
thumb_up_alt
0
like
thumb_down_alt
0
dislike
70
views
1
answer
asked
Mar 20, 2018
by
anonymous
The starting resistance of a D.C. motor is generally?
Last answer:
The starting resistance of a D.C. motor is generally low.
starting
resistance
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
76
views
1
answer
asked
Mar 20, 2018
by
anonymous
By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?
Last answer:
By looking at Commutator part of the motor, it can be easily confirmed that a particular motor is D.C. motor.
motor
dc
thumb_up_alt
0
like
thumb_down_alt
0
dislike
79
views
1
answer
asked
Mar 20, 2018
by
anonymous
If the field of a D.C. shunt motor gets opened while motor is running?
Last answer:
If the field of a D.C. shunt motor gets opened while motor is running the motor will attain dangerously high speed.
field
dc
shunt
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
92
views
1
answer
asked
Mar 20, 2018
by
anonymous
If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor?
Last answer:
If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor is to be derated by a factor recommended by manufacturer and select the next higher H.P. motor.
ambient
temperature
motor
dc
thumb_up_alt
0
like
thumb_down_alt
0
dislike
75
views
1
answer
asked
Mar 20, 2018
by
anonymous
For a D.C. shunt motor if the excitation is changed?
Last answer:
For a D.C. shunt motor if the excitation is changed torque will change but power will remain constant.
dc
shunt
motor
excitation
thumb_up_alt
0
like
thumb_down_alt
0
dislike
122
views
1
answer
asked
Mar 20, 2018
by
anonymous
If a D.C. motor is connected across the A.C. supply it will?
Last answer:
If a D.C. motor is connected across the A.C. supply it will burn due to heat produced in the field winding by eddy currents.
dc
motor
connected
ac
thumb_up_alt
0
like
thumb_down_alt
0
dislike
75
views
1
answer
asked
Apr 29, 2018
by
anonymous
In a DC motor, it is important to place the brushes along ______
In a DC motor, it is important to place the brushes along ______ A) Magnetic Neutral Axis B) Normal Geometric Axis C) Nominal Geometric Axis D) None of these
Last answer:
In a DC motor, it is important to place the brushes along Magnetic Neutral Axis
dc
motor
brushes
thumb_up_alt
0
like
thumb_down_alt
0
dislike
65
views
1
answer
asked
Mar 20, 2018
by
anonymous
The speed of a D.C. motor can be controlled by varying
The speed of a D.C. motor can be controlled by varying 1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above
Last answer:
The speed of a D.C. motor can be controlled by varying 1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above
speed
dc
motor
varying
thumb_up_alt
0
like
thumb_down_alt
0
dislike
112
views
1
answer
asked
Mar 20, 2018
by
anonymous
In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will?
Last answer:
In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will remain unchanged.
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
146
views
1
answer
asked
Mar 20, 2018
by
anonymous
The speed of a D.C. shunt motor can be increased by?
Last answer:
The speed of a D.C. shunt motor can be increased by increasing the resistance in field circuit.
speed
dc
shunt
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
88
views
1
answer
asked
Mar 20, 2018
by
anonymous
Sparking at the commutator of a D.C. motor may result in?
Last answer:
Sparking at the commutator of a D.C. motor may result in damage to commutator segments, damage to commutator insulation, increased power consumption.
sparking
commutator
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
109
views
1
answer
asked
Mar 20, 2018
by
anonymous
In case the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be?
Last answer:
In case the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be less than 50%.
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
96
views
1
answer
asked
Mar 20, 2018
by
anonymous
In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be?
Last answer:
In a D.C. shunt motor, under the conditions of maximum power, the current in the armature will be more than full-load current.
dc
shunt
motor
conditions
maximum
power
current
armature
thumb_up_alt
0
like
thumb_down_alt
0
dislike
169
views
1
answer
asked
Mar 20, 2018
by
anonymous
The speed of a D.C. shunt motor more than its full-load speed can be obtained by?
Last answer:
The speed of a D.C. shunt motor more than its full-load speed can be obtained by decreasing the field current.
dc
shunt
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
91
views
1
answer
asked
Mar 20, 2018
by
anonymous
The direction of rotation of a D.C. series motor can be changed by?
Last answer:
The direction of rotation of a D.C. series motor can be changed by interchanging field terminals.
direction
rotation
dc
series
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
75
views
1
answer
asked
Jul 5, 2019
by
anonymous
Why does the speed of a DC shunt motor decrease as the load increases?
Why does the speed of a DC shunt motor decrease as the load increases?
Last answer:
Because if the load is increasing then the torque must also be increase. If not then the speed of motor will decrease.
why
does
the
speed
of
a
dc
shunt
motor
decrease
as
load
increases
thumb_up_alt
0
like
thumb_down_alt
0
dislike
2.5k
views
1
answer
asked
Apr 28, 2018
by
anonymous
The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a
The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ (A) directly proportional to α and Φ (B) inversely proportional to α and Φ (C) directly proportional to α and inversely proportional to Φ (D) directly proportional to Φ and inversely proportional to α
Last answer:
The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a firing delay angle, α and flux, Φ directly proportional to α and inversely proportional to Φ
no-load
speed
single-phase
scr
bridge
converter
fed
separately
excited
dc
motor
operating
thumb_up_alt
0
like
thumb_down_alt
0
dislike
122
views
1
answer
asked
Apr 28, 2018
by
anonymous
In a 4-pole wave winding connected dc motor, the cross-magnetizing AT/pole for a brush shift of θ radians
In a 4-pole wave winding connected dc motor, the cross-magnetizing AT/pole for a brush shift of θ radians (A) Armature amp-conductors × (θ/360o) (B) Armature amp-turns × (θ/360o) (C) Armature amp-conductors × (1/4 - θ/360o) (D) Armature amp-conductors × (1/8 - θ/360o)
Last answer:
In a 4-pole wave winding connected dc motor, the cross-magnetizing AT/pole for a brush shift of θ radians Armature amp-conductors × (1/8 - θ/360o)
dc
motor
cross-magnetizing
brush
shift
thumb_up_alt
0
like
thumb_down_alt
0
dislike
78
views
1
answer
asked
Mar 20, 2018
by
anonymous
Sparking, is discouraged in a D.C. motor because?
Last answer:
Sparking, is discouraged in a D.C. motor because commutator gets damaged.
sparking
discouraged
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
94
views
1
answer
asked
Mar 20, 2018
by
anonymous
If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens?
Last answer:
If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses.
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
95
views
1
answer
asked
Mar 20, 2018
by
anonymous
In a D.C. shunt motor, speed is?
Last answer:
In a D.C. shunt motor, speed is independent of armature current.
dc
shunt
motor
speed
thumb_up_alt
0
like
thumb_down_alt
0
dislike
61
views
1
answer
asked
Mar 20, 2018
by
anonymous
For starting a D.C. motor a starter is required because?
Last answer:
For starting a D.C. motor a starter is required because it limits the starting current to a safe value.
starting
dc
motor
starter
thumb_up_alt
0
like
thumb_down_alt
0
dislike
62
views
1
answer
asked
Mar 20, 2018
by
anonymous
A D.C. series motor is that which?
Last answer:
A D.C. series motor is that which has its field winding consisting of thick wire and less turns.
dc
series
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
51
views
1
answer
asked
Mar 20, 2018
by
anonymous
If a D.C. series motor is operated on A.C. supply, it will?
Last answer:
If a D.C. series motor is operated on A.C. supply, it will spark excessively, have poor efficiency, have poor power factor.
dc
series
motor
operated
ac
supply
thumb_up_alt
0
like
thumb_down_alt
0
dislike
63
views
1
answer
asked
Apr 30, 2018
by
anonymous
A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling
A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling diode is open circuited, then the motor : (A) can be operated in first quadrant (B) can be operated in first & second quadrants (C) can be operated in first & fourth quadrants (D) cannot be operated
Last answer:
A separately excited dc motor operating in first quadrant is fed from 3-phase semi -converter free -wheeling diode is open circuited, then the motor : can be operated in first & fourth quadrants
separately
excited
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
162
views
1
answer
asked
Mar 20, 2018
by
anonymous
The armature torque of the D.C. shunt motor is proportional to?
Last answer:
The armature torque of the D.C. shunt motor is proportional to armature current.
armature
torque
dc
shunt
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
87
views
1
answer
asked
Mar 20, 2018
by
anonymous
As the load is increased the speed of D.C. shunt motor will?
Last answer:
As the load is increased the speed of D.C. shunt motor will reduce slightly.
load
increased
speed
dc
shunt
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
105
views
1
answer
asked
Mar 20, 2018
by
anonymous
The condition for maximum power in case of D.C. motor is?
condition
maximum
power
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
83
views
0
answers
asked
Mar 20, 2018
by
anonymous
The current drawn by the armature of D.C. motor is directly proportional to?
Last answer:
The current drawn by the armature of D.C. motor is directly proportional to the torque required.
dc
motor
thumb_up_alt
0
like
thumb_down_alt
0
dislike
303
views
1
answer
asked
Mar 20, 2018
by
anonymous
The type of D.C. motor used for shears and punches is?
Last answer:
The type of D.C. motor used for shears and punches is cumulative compound D.C. motor.
type
dc
motor
used
shears
punches
thumb_up_alt
0
like
thumb_down_alt
0
dislike
101
views
1
answer
Install Now
...