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During rheostat braking of D.C. series motors?
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asked
Mar 20, 2018
by
anonymous
rheostat
braking
dc
series
motors
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Answer
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answered
Mar 20, 2018
by
anonymous
During rheostat braking of D.C. series motors
motor is run as a generator.
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Mar 20, 2018
by
anonymous
Correct it If answer is wrong?
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Related questions
asked
Mar 20, 2018
by
anonymous
In case of conductively compensated D.C. series motors, the compensating winding is provided?
Last answer:
In case of conductively compensated D.C. series motors, the compensating winding is provided in series with armature winding.
dc
motors
series
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1
answer
asked
Mar 20, 2018
by
anonymous
When two D.C. series motors are connected in parallel, the resultant speed is?
Last answer:
When two D.C. series motors are connected in parallel, the resultant speed is normal speed.
dc
series
motors
speed
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305
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1
answer
asked
Mar 20, 2018
by
anonymous
For which types of D.C. motor, dynamic braking is generally used ?
Last answer:
Shunt motors, Series motors, Compound motors
types
dc
motor
dynamic
braking
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1
answer
asked
Mar 20, 2018
by
anonymous
D.C. shunt motors are used for driving?
Last answer:
D.C. shunt motors are used for driving machine tools.
dc
shunt
motors
used
driving
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68
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1
answer
asked
Mar 20, 2018
by
anonymous
Why are the D.C. motors preferred for traction applications?
Last answer:
The D.C. motors preferred for traction applications beacuse the speed is inversely proportional to the torque and the torque is proportional to square of armature current.
dc
motors
traction
applications
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100
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1
answer
asked
Mar 20, 2018
by
anonymous
In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to?
Last answer:
In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to improve power factor.
capacitor
start
run
motors
function
running
series
auxiliary
winding
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1
answer
asked
Mar 20, 2018
by
anonymous
In case of D.C. shunt motors the speed is dependent on back e.m.f. only because?
Last answer:
In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.
dc
shunt
motors
speed
back
emf
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146
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1
answer
asked
Mar 20, 2018
by
anonymous
In D.C. shunt motors as load is reduced?
Last answer:
In D.C. shunt motors as load is reduced the speed will remain almost constant.
dc
shunt
motors
load
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1
answer
asked
Mar 20, 2018
by
anonymous
Starters are used with D.C. motors because?
Last answer:
Starters are used with D.C. motors because to restrict armature current as there is no back e.m.f. while starting.
starters
used
dc
motors
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1
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asked
Mar 20, 2018
by
anonymous
Differentially compound D.C. motors can find applications requiring?
Last answer:
Differentially compound D.C. motors can find applications requiring low starting torque.
differentially
compound
dc
motors
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1
answer
asked
Mar 20, 2018
by
anonymous
Regenerative method of braking is based on that?
Last answer:
Regenerative method of braking is based on that back e.m.f. is equal to the applied voltage.
regenerative
method
braking
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69
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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
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1
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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
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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
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1
answer
asked
Mar 20, 2018
by
anonymous
When a D.C. series motor is connected to A.C. supply, the power factor will be low because of?
Last answer:
When a D.C. series motor is connected to A.C. supply, the power factor will be low because of high inductance of field and armature circuits.
dc
series
motor
the
power
factor
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1
answer
asked
Mar 21, 2018
by
anonymous
When two D.C. series generators are running in parallel, an equilizer bar is used?
Last answer:
If equalising bar is connected to the 2 DC generators the current will be equal in 2 generators irrespective of parallel connection so that we connect equaliser bar
series
generators
dc
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2
answers
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
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1
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asked
Mar 20, 2018
by
anonymous
A.C. series motor as compared to D.C. series motor has?
Last answer:
A.C. series motor as compared to D.C. series motor has smaller brush width, less number of field turns, more number of armature turns, less air gap.
ac
series
motor
compared
dc
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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
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1
answer
asked
Mar 25, 2018
by
anonymous
A rheostat differs from potentiometer in the respect that it?
A rheostat differs from potentiometer in the respect that it?
Last answer:
A rheostat differs from potentiometer in the respect that it has higher wattage rating.
rheostat
potentiometer
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66
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1
answer
asked
Aug 6, 2017
by
anonymous
what is Rheostat ?
what is Rheostat ?
Last answer:
Rheostat is varible resistance device which gives large range variation in resistance generally used for operating electrical motors
rheostat
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2
answers
asked
Apr 29, 2018
by
anonymous
Which of the following motors can run on both AC and DC?
Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
Last answer:
Which of the following motors can run on both AC and DC? A) Universal motor B) Dual wattage motor C) Flexible motor D) All the above
motors
ac
dc
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113
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1
answer
asked
Sep 3, 2019
by
anonymous
Why are DC motors used in trains and not AC motors ?
Why are DC motors used in trains and not AC motors ?
Last answer:
The reason is torque. torque is inversely proportional to speed..i.e when th knowe train comes to rest position to motion.. initial speed is zero..so it requires high starting torque for ... current will flow through field and armature coils then maximum torque is available at the intial condition.
dc
motors
trains
ac
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1
answer
asked
May 7, 2020
by
anonymous
State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.
State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.
Last answer:
Modifications are necessary in a dc series motor so that it operates satisfactorily on ac supply. The modifications are as follows: 1) AC series motor is built with a few field turns as ... and grinders 5) High speed vacuum cleaners 6) Sewing machines 7) Food processors 8) Drilling machine
state
the
modification
to
be
done
in
dc
series
motor
work
satisfactorily
as
ac
applications
of
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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
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114
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1
answer
asked
May 8, 2018
by
anonymous
We connected a 35V dc supply to a resistance of 600 Ohm in series with an unknown resistance
We connected a 35V dc supply to a resistance of 600 Ohm in series with an unknown resistance R.A. voltmeter having a resistance of 1.2 kOhm is connected across 600 Ohm resistance and read 5v. The value of resistance R will be
Last answer:
We connected a 35V dc supply to a resistance of 600 Ohm in series with an unknown resistance R.A. voltmeter having a resistance of 1.2 kOhm is connected across 600 Ohm resistance and read 5v. The value of resistance R will be 2.4 kOhm
dc
supply
resistance
series
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113
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1
answer
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
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80
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0
answers
asked
Mar 20, 2018
by
anonymous
Which method of braking is generally used in elevators ?
Last answer:
Plugging method of braking is generally used in elevators.
method
braking
elevators
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51
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1
answer
asked
Apr 21, 2020
by
anonymous
Brake test on DC series motor
Brake test on DC series motor
Last answer:
.embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
brake
test
on
dc
series
motor
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2
answers
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
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70
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1
answer
asked
Apr 29, 2018
by
anonymous
A DC voltage source is connected across a series RLC circuit. Under steady-state conditions, the applied DC
A DC voltage source is connected across a series RLC circuit. Under steady-state conditions, the applied DC voltage drops entirely across the
Last answer:
A DC voltage source is connected across a series RLC circuit. Under steady-state conditions, the applied DC voltage drops entirely across the C only
dc
voltage
source
series
rlc
circuit
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508
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1
answer
asked
Mar 15, 2018
by
anonymous
Why dc series motor should not be started at no load?
Why dc series motor should not be started at no load?
dc
series
motor
started
load
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597
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0
answers
asked
Mar 15, 2018
by
anonymous
Why a dc series motor has a high starting torque?
Why a dc series motor has a high starting torque?
dc
series
motor
high
starting
torque
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64
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0
answers
asked
Aug 9, 2019
by
anonymous
Explain in brief how anti-lock braking system works
Explain in brief how anti-lock braking system works
Last answer:
An ABS is a system on motor vehicles which prevents the wheels from locking while braking stopping safely is one of the most important functions a motor vehicle can perform. Diagram: ... to decrease the pressure on the braking circuit, effectively reducing the braking force on that wheel.
anti-lock
braking
system
works
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48
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1
answer
asked
Mar 22, 2018
by
anonymous
The braking retardation is usually in the range?
Last answer:
The braking retardation is usually in the range 10 to 15 km phps.
braking
retardation
usually
range
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203
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1
answer
asked
Apr 27, 2020
by
anonymous
Write two applications of D.C. series motor.
Write two applications of D.C. series motor.
Last answer:
The applications of D.C. series motor: 1. Cranes 2. Hoists 3. Trolley and cars 4. Conveyors 5. For traction work i.e. electric locomotives 6. Elevator 7. Air compressor
write
two
applications
of
d
c
series
motor
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58
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1
answer
asked
May 25, 2018
by
anonymous
The widely used series-parallel system of speed control of d.c. series motors in traction work gives a speed
The widely used series-parallel system of speed control of d.c. series motors in traction work gives a speed range of about (a) 1 : 2 (b) 1 : 3 (c) 1 : 4 (d) 1 : 6
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0
answers
asked
May 22, 2020
by
anonymous
Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.
Explain the necessity of starter for D.C. motor. State various types of D.C. motor starter.
Last answer:
Necessity of Starter for D.C. Motor: Armature current is given by equation Ia = (V−Eb)/Ra i) If the motor is at standstill or rest, back emf Eb is zero (as Eb= ZNP/(60A), at start speed N ... . Types of D.C. motor starters: i) Two point starter ii)Three point starter iii) Four point starter
starter
dc
motor
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81
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1
answer
asked
Mar 26, 2018
by
anonymous
The Eb/V ratio of a d.c. motor is an indication of its?
The Eb/V ratio of a d.c. motor is an indication of its?
Last answer:
The Eb/V ratio of a d.c. motor is an indication of its efficiency.
ratio
motor
indication
dc
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531
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1
answer
asked
Mar 26, 2018
by
anonymous
The normal value of the armature resistance of a d.c. motor is?
The normal value of the armature resistance of a d.c. motor is?
Last answer:
asked Mar 26, 2018 by anonymous The normal value of the armature resistance of a d.c. motor is?
dc
motor
armature
resistance
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757
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2
answers
asked
Mar 26, 2018
by
anonymous
The counter e.m.f. of a d.c. motor?
The counter e.m.f. of a d.c. motor?
Last answer:
The counter e.m.f. of a d.c. motor helps in energy conversion.
counter
emf
dc
motor
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60
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1
answer
asked
Mar 26, 2018
by
anonymous
In a d.c. motor, unidirectional torque is produced with the help of?
In a d.c. motor, unidirectional torque is produced with the help of
Last answer:
Commutator provides unidirectional torque and pulsating dc
dc
motor
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256
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1
answer
asked
Mar 20, 2018
by
anonymous
D.C. motor is to a drive a load which is almost nil for certain part of the load cycle...
D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select the?
Last answer:
D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select the compound motor.
dc
motor
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75
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1
answer
asked
Mar 20, 2018
by
anonymous
D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value...
D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the?
Last answer:
D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the series motor.
dc
motor
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206
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1
answer
asked
Mar 20, 2018
by
anonymous
When the armature of a D.C. motor rotates, e.m.f. induced is
Last answer:
When the armature of a D.C. motor rotates, e.m.f. induced is back e.m.f.
armature
dc
motor
rotates
emf
induced
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99
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1
answer
asked
Mar 20, 2018
by
anonymous
If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will?
Last answer:
If the speed of a D.C. shunt motor is increased, the back e.m.f. of the motor will increase.
speed
dc
shunt
motor
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111
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1
answer
asked
Mar 26, 2018
by
anonymous
A d.c. motor can be looked upon as d.c. generator with the power flow?
A d.c. motor can be looked upon as d.c. generator with the power flow?
Last answer:
A d.c. motor can be looked upon as d.c. generator with the power flow reversed.
dc
motor
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2.7k
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1
answer
asked
Mar 20, 2018
by
anonymous
Which D.C. motor has got maximum self relieving property ?
Last answer:
Series motor has got maximum self relieving property.
dc
motor
maximum
self
property
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129
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1
answer
asked
Mar 20, 2018
by
anonymous
If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens?
Last answer:
If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens this will make armature to take heavy current, possibly burning it.
dc
shunt
motor
working
full
load
field
circuit
suddenly
opens
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103
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1
answer
asked
Mar 20, 2018
by
anonymous
Torque developed by a D.C. motor depends upon?
Last answer:
Torque developed by a D.C. motor depends upon magnetic field, active length of the conductor, current flow through the conductors, number of conductors, radius of armature.
torque
developed
dc
motor
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...