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In a A.C. series motor armature coils are usually connected to commutator?
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asked
Mar 20, 2018
by
anonymous
ac
series
motor
armature
coils
usually
commutator
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answered
Mar 20, 2018
by
anonymous
In a A.C. series motor armature coils are usually connected to commutator
through resistance.
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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
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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 20, 2018
by
anonymous
In A.C. series motor compensating winding is employed to?
Last answer:
In A.C. series motor compensating winding is employed to reduce sparking at the brushes.
ac
series
motor
compensating
winding
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99
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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
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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
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1
answer
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
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1
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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
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
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175
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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
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1
answer
asked
Mar 20, 2018
by
anonymous
The armature voltage control of D.C. motor provides?
Last answer:
The armature voltage control of D.C. motor provides constant torque drive.
armature
voltage
control
motor
dc
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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 20, 2018
by
anonymous
In a shaded pole motor, the shading coil usually consist of?
Last answer:
In a shaded pole motor, the shading coil usually consist of a single turn of heavy copper wire which is short-circuited and carries only induced current.
shaded
pole
motor
shading
coil
usually
consist
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64
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1
answer
asked
Mar 20, 2018
by
anonymous
The efficiency of a properly designed synchronous motor will usually fall in range?
Last answer:
The efficiency of a properly designed synchronous motor will usually fall in range 85 to 95%.
efficiency
designed
synchronous
motor
usually
range
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1
answer
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
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175
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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
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71
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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
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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
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
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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
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127
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2
answers
asked
Mar 20, 2018
by
anonymous
The power factor of a single-phase induction motor is usually?
Last answer:
The power factor of a single-phase induction motor is usually lagging.
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factor
single-phase
induction
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usually
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102
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1
answer
asked
Mar 20, 2018
by
anonymous
The commutator segments are connected to the armature conductors by means of?
Last answer:
The commutator segments are connected to the armature conductors by means of copper lugs.
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conductors
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119
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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
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75
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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:
The normal value of the armature resistance of a d.c. motor is 0.5.
dc
motor
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resistance
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765
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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
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motor
rotates
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100
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1
answer
asked
Mar 20, 2018
by
anonymous
In a synchronous motor, the armature current has large values for?
Last answer:
In a synchronous motor, the armature current has large values for high and low excitation.
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motor
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88
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1
answer
asked
Mar 3, 2018
by
anonymous
From which material field coils of DC generator are made of?
From which material field coils of DC generator are made of?
Last answer:
Field coils of DC generator are usually made of copper.
material
field
coils
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generator
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97
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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
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series
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trains
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115
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1
answer
asked
Mar 20, 2018
by
anonymous
The armature current of the synchronous motor?
Last answer:
The armature current of the synchronous motor has large values for low and high excitation.
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current
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motor
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67
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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.
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series
motors
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306
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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
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 21, 2018
by
anonymous
To avoid formation of grooves in the commutator of a D.C. machine?
Last answer:
To avoid formation of grooves in the commutator of a D.C. machine the brushes of opposite polarity should track each other.
commutator
dc
machine
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2.9k
views
1
answer
asked
Mar 15, 2018
by
anonymous
What are the parts of AC motor?
What are the parts of AC motor?
parts
ac
motor
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46
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0
answers
asked
Apr 29, 2018
by
anonymous
Which of the following does not have a commutator?
Which of the following does not have a commutator? A) Dynamo B) Induction motor C) Universal motor D) None of these
Last answer:
Which of the following does not have a commutator? A) Dynamo B) Induction motor C) Universal motor D) None of these
commutator
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127
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1
answer
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
Mar 20, 2018
by
anonymous
The armature core of a D.C. generator is usually made of?
Last answer:
The armature core of a D.C. generator is usually made of silicon steel.
armature
core
dc
generator
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85
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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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160
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2
answers
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
views
0
answers
asked
Mar 21, 2018
by
anonymous
The purpose of providing dummy coils in a generator is?
Last answer:
The purpose of providing dummy coils in a generator is to provide mechanical balance for the rotor.
dummy
coils
generator
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242
views
1
answer
asked
Mar 11, 2018
by
anonymous
Explain series switching control of AC load.
Explain series switching control of AC load. Single phase resistance load - Integral half cycle control Phase control - Resistance load
series
switching
control
ac
load
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50
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0
answers
asked
Mar 26, 2018
by
anonymous
The induced e.m.f. in the armature conductors of a d.c. motor is?
The induced e.m.f. in the armature conductors of a d.c. motor is?
Last answer:
The induced e.m.f. in the armature conductors of a d.c. motor is sinusoidal.
armature
conductors
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334
views
1
answer
asked
May 1, 2018
by
anonymous
In dc machines, the armature windings are placed on the rotor because of the necessity for
In dc machines, the armature windings are placed on the rotor because of the necessity for (1) electromechanical energy conversion (2) generation of voltage (3) commutation (4) development of torque
Last answer:
3 Commutation
dc
machines
armature
windings
rotor
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189
views
2
answers
asked
Mar 15, 2018
by
anonymous
What is the principle of AC motor?
What is the principle of AC motor?
principle
ac
motor
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53
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0
answers
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
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73
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1
answer
asked
Aug 9, 2017
by
anonymous
what is AC motor?
AC motor
Last answer:
AC motor AC motor have two types one is Induction motor and second is synchronous motor. Induction motor have two types one is single phase induction motor and second is three phase ... self starting motor so using external motor or we have to start it as induction motor.
ac
motor
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72
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1
answer
asked
Mar 22, 2018
by
anonymous
The voltage used for suburban trains in D.C. system is usually?
Last answer:
The voltage used for suburban trains in D.C. system is usually 600 to 750 V.
voltage
used
suburban
trains
dc
system
usually
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66
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1
answer
asked
Mar 21, 2018
by
anonymous
The two pressure coils of a single phase power factor meter have?
Last answer:
The two pressure coils of a single phase power factor meter have the same dimensions and the same number of turns.
two
pressure
coils
single
phase
power
factor
meter
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74
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1
answer
asked
Mar 20, 2018
by
anonymous
The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it?
Last answer:
The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it helps in reducing the tendency of the rotor teeth to remain under the stator teeth.
induction
motor
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119
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1
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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
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307
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1
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asked
Mar 25, 2018
by
anonymous
Two resistors are said to be connected in series when?
Two resistors are said to be connected in series when?
Last answer:
Two resistors are said to be connected in series when same current passes in turn through both.
resistors
series
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