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If we change the excitation of synchronous machine will it affect on motor speed?
asked
Mar 18, 2018
by
anonymous
If we change the excitation of synchronous machine will it affect on motor speed?
change
excitation
synchronous
machine
affect
motor
speed
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1
Answer
answered
Mar 18, 2018
by
anonymous
No,
If we change the excitation of synchronous machine it will not affect on motor speed.
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asked
Mar 18, 2018
by
anonymous
If we change the excitation of synchronous machine will it affect on power factor?
If we change the excitation of synchronous machine will it affect on power factor?
Last answer:
Yes, If we change the excitation of synchronous machine it will affect on power factor. If the synchronous motor is overexcited then it will have leading power factor and if the motor is underexcited then it will have lagging power factor.
change
excitation
synchronous
machine
affect
power
factor
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1
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1
asked
Mar 18, 2018
by
anonymous
what will happen when excitation of an unloaded salient pole synchronous motor suddenly gets disconnected?
what will happen when excitation of an unloaded salient pole synchronous motor suddenly gets disconnected?
Last answer:
When excitation of an unloaded salient pole synchronous motor suddenly gets disconnected the motor will stop.
excitation
unloaded
salient
pole
synchronous
motor
disconnected
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270
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1
answer
2
asked
Mar 6, 2018
by
anonymous
Can we make power factor of synchronous motor leading by adjusting its excitation?
Last answer:
Yes, we can make the power factor of synchronous motor leading by adjusting its excitation.
power
factor
synchronous
motor
leading
adjusting
excitation
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83
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1
answer
3
asked
Mar 20, 2018
by
anonymous
A synchronous motor running with normal excitation adjusts to load increases essentially by increase in?
Last answer:
A synchronous motor running with normal excitation adjusts to load increases essentially by increase in armature current.
synchronous
motor
running
normal
excitation
load
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1
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4
asked
Apr 28, 2018
by
anonymous
The effect of increasing load on a synchronous motor running with normal excitation is
The effect of increasing load on a synchronous motor running with normal excitation is (A) Increase both its Ia and power factor. (B) Decrease Ia, but increase power factor. (C) Increase Ia, but decrease power factor (D) Decrease both Ia and power factor.
Last answer:
The effect of increasing load on a synchronous motor running with normal excitation is Increase Ia, but decrease power factor
effect
load
synchronous
motor
running
normal
excitation
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5
asked
Mar 20, 2018
by
anonymous
In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will?
Last answer:
In case of a reluctance motor, when the load is increased so that it cannot maintain synchronous speed the motor will run as induction motor.
reluctance
motor
synchronous
speed
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1
answer
6
asked
Mar 20, 2018
by
anonymous
If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in?
Last answer:
If the centrifugal switch does not open at 70 to 80 percent of synchronous speed of motor, it would result in damage to the starting winding.
synchronous
speed
motor
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1
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7
asked
Mar 20, 2018
by
anonymous
The operating speed of a synchronous motor can be changed to new fixed value by?
Last answer:
The operating speed of a synchronous motor can be changed to new fixed value by changing frequency.
operating
speed
synchronous
motor
fixed
value
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1
answer
8
asked
Mar 18, 2018
by
anonymous
Synchronous motor always runs at which speed?
Synchronous motor always runs at which speed?
Last answer:
Synchronous motor always runs at synchronous speed.
synchronous
motor
always
runs
speed
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55
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1
answer
9
asked
Dec 31, 2017
by
anonymous
The synchronous speed of an 8 pole induction motor supplied power from a 50 Hz source will be ?
The synchronous speed of an 8 pole induction motor supplied power from a 50 Hz source will be ?
Last answer:
Ns equals f/pair pole 50/4 - 12.5
induction
motor
synchronous
speed
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119
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2
answers
10
asked
Mar 20, 2018
by
anonymous
Centrifugal switch disconnects the auxiliary winding of the motor at about what percent of synchronous speed?
Last answer:
Centrifugal switch disconnects the auxiliary winding of the motor at about 70 to 80 percent of synchronous speed.
centrifugal
switch
disconnects
auxiliary
winding
motor
synchronous
speed
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138
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1
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11
asked
Mar 15, 2018
by
anonymous
Why the speed of synchronous motor is constant?
Why the speed of synchronous motor is constant?
speed
synchronous
motor
constant
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12
asked
Apr 29, 2018
by
anonymous
In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load
In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load (A) The armature current increases and the power factor decreases (B) The armature current decreases and the power factor also decreases (C) The armature current decreases and the power factor increases but is lagging (D) The armature current decreases and the power factor increases and is leading
Last answer:
In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load The armature current decreases and the power factor increases and is leading
synchronous
generator
excitation
normal
value
fixed
load
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1
answer
13
asked
Mar 20, 2018
by
anonymous
If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will?
Last answer:
If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.
field
winding
unloaded
salient
pole
synchronous
motor
open
circuited
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115
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1
answer
14
asked
Mar 18, 2018
by
anonymous
If the load of the normally excited synchronous motor is increased the power factor will?
If the load of the normally excited synchronous motor is increased the power factor will?
Last answer:
If the load of the normally excited synchronous motor is increased the power factor will become lagging.
load
normally
excited
synchronous
motor
increased
power
factor
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1
answer
15
asked
Mar 18, 2018
by
anonymous
If the field of synchronous motor is under excited, power factor will be?
If the field of synchronous motor is under excited, power factor will be?
Last answer:
If the field of synchronous motor is under excited, power factor will be lagging.
field
synchronous
motor
excited
power
factor
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143
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1
answer
16
asked
Mar 18, 2018
by
anonymous
V - curve of synchronous machine shows the relation between?
V - curve of synchronous machine shows the relation between?
Last answer:
V - curve of synchronous machine shows the relation between AC armature current and DC field current.
synchronous
machine
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53
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1
answer
17
asked
Mar 18, 2018
by
anonymous
Which machine is the exciter of synchronous machine?
Which machine is the exciter of synchronous machine?
Last answer:
DC shunt machine is the exciter of synchronous machine.
machine
exciter
synchronous
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41
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1
answer
18
asked
Mar 20, 2018
by
anonymous
Synchronsizing power of a synchronous machine is?
Last answer:
Synchronsizing power of a synchronous machine is inversely proportional to the synchronous reactance.
synchronsizing
power
synchronous
machine
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1
answer
19
asked
Mar 20, 2018
by
anonymous
A synchronous machine with low value of short-circuit ratio has?
Last answer:
A synchronous machine with low value of short-circuit ratio has lower stability limit.
synchronous
machine
low
value
short-circuit
ratio
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75
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1
answer
20
asked
Mar 20, 2018
by
anonymous
If the synchronous motor, properly synchronised to the supply is running on no load and is having negligible loss then?
Last answer:
If the synchronous motor, properly synchronised to the supply is running on no load and is having negligible loss then the stator current will be zero.
synchronous
motor
synchronised
supply
running
load
negligible
loss
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87
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1
answer
21
asked
Mar 18, 2018
by
anonymous
Why synchronous machine is called doubly excited machine?
Why synchronous machine is called doubly excited machine?
Last answer:
Armature windings of synchronous machines either deliver 3 phase AC or absorb 3 phase AC source, whereas field windings are energized from DC source. Thus due to presence of AC on armature and DC on field windings, synchronous machines are often referred as doubly excited machines.
synchronous
machine
doubly
excited
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2
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22
asked
Mar 18, 2018
by
anonymous
How can we reverse the direction of rotation of synchronous motor?
How can we reverse the direction of rotation of synchronous motor?
Last answer:
By reversing supply phase sequence we can reverse the direction of rotation of synchronous motor.
reverse
direction
rotation
synchronous
motor
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183
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1
answer
23
asked
Mar 18, 2018
by
anonymous
Can we use the synchronous motor as the synchronous capacitor?
Can we use the synchronous motor as the synchronous capacitor?
Last answer:
Yes, we can use the synchronous motor as the synchronous capacitor when the synchrnous motor is overexcited.
use
synchronous
motor
capacitor
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76
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1
answer
24
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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1
answer
25
asked
Apr 29, 2018
by
anonymous
The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole)
The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) (A) has q -axis current only (B) has d -axis current only (C) has both d and q axis currents (D) cannot be divided between q and d axis currents
Last answer:
The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) has d -axis current only
armature
current
symmetrical
phase
short
circuit
synchronous
machine
salient
pole
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112
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1
answer
26
asked
May 1, 2018
by
anonymous
In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation,
In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as (1) synchronous motor (2) synchronous generator (3) asynchronous motor (4) asynchronous generator
Last answer:
In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as synchronous generator
synchronous
machine
field
flux
axis
armature
direction
rotation
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310
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1
answer
27
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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55
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1
answer
28
asked
Mar 20, 2018
by
anonymous
In case one phase of a three-phase synchronous motor is short-circuited the motor will?
Last answer:
In case one phase of a three-phase synchronous motor is short-circuited the motor will not start.
one
phase
three-phase
synchronous
motor
short-circuited
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171
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1
answer
29
asked
Mar 20, 2018
by
anonymous
The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor...
The maximum torque which a synchronous motor will develop at rest for any angular position of the rotor, at rated stator supply voltage and frequency, is known as?
maximum
torque
synchronous
motor
rated
stator
supply
voltage
frequency
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86
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0
answers
30
asked
Apr 29, 2018
by
anonymous
During a disturbance on a synchronous machine, the rotor swings form A to B before finally setting down to
During a disturbance on a synchronous machine, the rotor swings form A to B before finally setting down to steady state at point C on the power angle curve. The speed of the machine during oscillation is synchronous at point(s)
Last answer:
During a disturbance on a synchronous machine, the rotor swings form A to B before finally setting down to steady state at point C on the power angle curve. The speed of the machine during oscillation is synchronous at point(s) only at C
disturbance
synchronous
machine
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151
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1
answer
31
asked
Mar 20, 2018
by
anonymous
The maximum constant load torque under which a synchronous motor will pull into synchronism...
The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as?
Last answer:
The maximum constant load torque under which a synchronous motor will pull into synchronism at rated rotor supply voltage and frequency is known as pull-in torque.
maximum
constant
load
torque
synchronous
motor
synchronism
rated
rotor
supply
voltage
frequency
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213
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1
answer
32
asked
Mar 18, 2018
by
anonymous
The synchronous motor will develop maximum power when the load angle is?
The synchronous motor will develop maximum power when the load angle is?
Last answer:
The synchronous motor will develop maximum power when the load angle is 900.
synchronous
motor
develop
maximum
power
load
angle
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80
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1
answer
33
asked
Mar 20, 2018
by
anonymous
The duration of sudden short-circuit test on a synchronous motor is usually about?
Last answer:
The duration of sudden short-circuit test on a synchronous motor is usually about one second.
short-circuit
test
synchronous
motor
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113
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1
answer
34
asked
Mar 18, 2018
by
anonymous
The back emf of synchronous motor depends on?
The back emf of synchronous motor depends on?
Last answer:
The back emf of synchronous motor depends on load angle.
back
emf
synchronous
motor
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47
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1
answer
35
asked
Mar 18, 2018
by
anonymous
Three phase synchronous motor will have how many sliprings?
Three phase synchronous motor will have how many sliprings?
Last answer:
Three phase synchronous motor will have two sliprings.
three
phase
synchronous
motor
slipring
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63
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1
answer
36
asked
Mar 18, 2018
by
anonymous
The synchronous motor which works on leading power factor and does not drive any mechanical load is called?
The synchronous motor which works on leading power factor and does not drive any mechanical load is called?
Last answer:
The synchronous motor which works on leading power factor and does not drive any mechanical load is called synchronous condenser.
synchronous
motor
leading
power
factor
drive
mechanical
load
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69
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1
answer
37
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
38
asked
Apr 30, 2018
by
anonymous
The 'Equal area criterion' for the determination of transient stability of a synchronous machine connected to
The 'Equal area criterion' for the determination of transient stability of a synchronous machine connected to an infinite bus (1) ignores line as well as synchronous machine resistance and shunt capacitances. (2) assumes accelerating power acting on the rotor as constant. (3) ignores the effect of voltage ... inherent damping present in the machine. (4) takes into consideration the possibility of machine losing synchronism after it has survived during the first swing.
Last answer:
1
equal
area
criterion
transient
stability
synchronous
machine
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2
answers
39
asked
May 7, 2020
by
anonymous
Define Feed and speed in shaping machine
Define Feed and speed in shaping machine
Last answer:
1) Feed: Feed (S) is the relative movement of the work or tool in a direction perpendicular to the axis of reciprocation of the ram per double stroke. It is expressed in mm per stroke. 2) Speed: ... speed is the speed at which the metal is removed by the cutting tool in a period of one minute.
define
feed
and
speed
in
shaping
machine
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45
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1
answer
40
asked
Apr 28, 2018
by
anonymous
Torque angle for the synchronous machine is the angle between
Torque angle for the synchronous machine is the angle between (A) stator magnetic field and rotor magnetic field (B) stator magnetic field and net magnetic field in the air gap (C) rotor magnetic field and net magnetic field in the air gap (D) excitation voltage and impedance voltage drop
Last answer:
Torque angle for the synchronous machine is the angle between rotor magnetic field and net magnetic field in the air gap
torque
angle
synchronous
machine
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71
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1
answer
41
asked
Mar 20, 2018
by
anonymous
The size of a synchronous motor decreases with the increase in?
Last answer:
The size of a synchronous motor decreases with the increase in flux density.
size
synchronous
motor
decreases
increase
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132
views
1
answer
42
asked
Mar 20, 2018
by
anonymous
The construction of a synchronous motor resembles?
Last answer:
The construction of a synchronous motor resembles an alternator.
construction
synchronous
motor
resembles
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55
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1
answer
43
asked
Mar 20, 2018
by
anonymous
The coupling angle or load angle of synchronous motor is defined as the angle between the?
Last answer:
The coupling angle or load angle of synchronous motor is defined as the angle between the rotor and the stator poles of opposite polarity.
coupling
angle
load
synchronous
motor
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135
views
1
answer
44
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.
armature
current
synchronous
motor
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67
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1
answer
45
asked
Mar 18, 2018
by
anonymous
What is the maximum value of torque angle in synchronous motor?
What is the maximum value of torque angle in synchronous motor?
Last answer:
The maximum value of torque angle in synchronous motor is 90 degrees electrical.
maximum
torque
angle
synchronous
motor
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698
views
1
answer
46
asked
Mar 20, 2018
by
anonymous
The wattage of motor for driving domestic sewing machine will be around?
Last answer:
The wattage of motor for driving domestic sewing machine will be around 100 to 150 W.
wattage
motor
driving
domestic
sewing
machine
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75
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1
answer
47
asked
Mar 18, 2018
by
anonymous
An electric motor in which both stator field and rotor rotates with same speed is called?
An electric motor in which both stator field and rotor rotates with same speed is called?
Last answer:
An electric motor in which both stator field and rotor rotates with same speed is called synchronous motor.
electric
motor
stator
field
rotor
rotates
speed
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91
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1
answer
48
asked
Mar 20, 2018
by
anonymous
A synchronous motor has better power factor as compared to that of an equivalent induction motor...
A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because?
Last answer:
A synchronous motor has better power factor as compared to that of an equivalent induction motor. This is mainly because stator supply is not required to produce magnetic field.
synchronous
power
factor
equivalent
induction
motor
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0
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86
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1
answer
49
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.
synchronous
motor
armature
current
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88
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