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Which D.C. motor is preferred for elevators ?
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asked
Mar 20, 2018
by
anonymous
dc
motor
preferred
elevators
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1
Answer
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answered
Mar 20, 2018
by
anonymous
Cumulative compound
D.C. motor is preferred for elevators.
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Related questions
asked
Mar 20, 2018
by
anonymous
Which D.C. motor is generally preferred for cranes and hoists ?
Last answer:
D.C. Series motor is generally preferred for cranes and hoists.
dc
motor
cranes
hoists
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76
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1
answer
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
Mar 20, 2018
by
anonymous
Which D.C. motor will be suitable along with flywheel for intermittent light and heavy loads?
Last answer:
Cumulatively compounded D.C. motor will be suitable along with flywheel for intermittent light and heavy loads.
dc
motor
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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
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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
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126
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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
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answers
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
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101
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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
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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
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1
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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
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
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96
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1
answer
asked
Mar 20, 2018
by
anonymous
If a D.C. motor is to be selected for conveyors, which motor would be preferred ?
Last answer:
If a D.C. motor is to be selected for conveyors, Series motor would be preferred.
motor
conveyors
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81
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1
answer
asked
Mar 20, 2018
by
anonymous
Which D.C. motor has got maximum self loading property?
Last answer:
Differentially compounded D.C. motor has got maximum self loading property.
dc
motor
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1
answer
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
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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
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1
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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
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
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106
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1
answer
asked
Mar 20, 2018
by
anonymous
Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be?
Last answer:
Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be cumulatively compounded.
dc
motor
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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
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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
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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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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 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
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1
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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
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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 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
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94
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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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63
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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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1
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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
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
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
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115
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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
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148
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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
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88
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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
In a differentially compounded D.C. motor, if shunt field suddenly opens?
Last answer:
In a differentially compounded D.C. motor, if shunt field suddenly opens the motor will first stop and then run in opposite direction as series motor.
dc
motor
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70
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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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111
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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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173
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1
answer
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
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378
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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
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91
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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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75
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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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69
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1
answer
asked
Mar 19, 2018
by
anonymous
Why thyristor are not preferred for inverter?
Why thyristor are not preferred for inverter?
thyristor
preferred
inverter
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432
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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 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
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
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
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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257
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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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...