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Why the speed of synchronous motor is constant?
asked
Mar 15, 2018
by
anonymous
Why the speed of synchronous motor is constant?
speed
synchronous
motor
constant
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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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87
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1
answer
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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139
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1
answer
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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69
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1
answer
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
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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83
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1
answer
asked
Mar 18, 2018
by
anonymous
If we change the excitation of synchronous machine will it affect on motor speed?
If we change the excitation of synchronous machine will it affect on motor speed?
Last answer:
No, If we change the excitation of synchronous machine it will not affect on motor speed.
change
excitation
synchronous
machine
affect
motor
speed
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68
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1
answer
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
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
asked
Mar 20, 2018
by
anonymous
For constant torque drive which speed control method is preferred ?
Last answer:
For constant torque drive armature voltage control speed control method is preferred.
constant
torque
drive
speed
control
method
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86
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1
answer
asked
Mar 15, 2018
by
anonymous
Why synchronous motor Cannot start itself?
Why synchronous motor Cannot start itself?
synchronous
motor
start
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59
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0
answers
asked
May 1, 2018
by
anonymous
The speed of a three-phase induction motor is controlled by variable voltage variable frequency control
The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque (1) Decreases (2) Increases (3) Remains constant (4) None of the above
Last answer:
The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases
speed
three-phase
induction
motor
controlled
variable
voltage
frequency
control
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118
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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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105
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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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70
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1
answer
asked
Mar 20, 2018
by
anonymous
The speed of a universal motor is usually reduced by using?
Last answer:
The speed of a universal motor is usually reduced by using gearing.
speed
universal
motor
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77
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1
answer
asked
Mar 20, 2018
by
anonymous
The speed/load characteristics of a universal motor is same as that of?
Last answer:
The speed/load characteristics of a universal motor is same as that of D.C. series motor.
speed
load
characteristics
universal
motor
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69
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1
answer
asked
Mar 20, 2018
by
anonymous
The speed control of universal motor used for sewing machines is by?
Last answer:
The speed control of universal motor used for sewing machines is by varying the resistance.
speed
control
universal
motor
used
sewing
machines
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69
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1
answer
asked
Mar 20, 2018
by
anonymous
Speed control of a universal motor is achieved by?
Last answer:
Speed control of a universal motor is achieved by varying field flux with tapped field windings, connecting rheostat in series, applying variable voltage by means of silicon controlled rectifier, applying variable voltage by means of variable auto-transformer.
speed
control
universal
motor
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76
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1
answer
asked
Mar 20, 2018
by
anonymous
Speed torque characteristic of a repulsion induction motor is similar to that of a D.C.?
Last answer:
Speed torque characteristic of a repulsion induction motor is similar to that of a D.C. compound motor.
speed
torque
characteristic
repulsion
induction
motor
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68
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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
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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
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220
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1
answer
asked
Apr 28, 2018
by
anonymous
The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min
The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min (A) 100 rpm (B) 200 rpm (C) 400 rpm (D) 800 rpm
Last answer:
The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min 200 rpm
speed
2-pole
3-phase
stepper
motor
operated
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121
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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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112
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
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88
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
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2
answers
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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399
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1
answer
asked
Mar 15, 2018
by
anonymous
What is the principle of synchronous motor?
What is the principle of synchronous motor?
principle
synchronous
motor
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54
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0
answers
asked
Mar 15, 2018
by
anonymous
What is the use of synchronous motor?
What is the use of synchronous motor?
use
synchronous
motor
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57
views
0
answers
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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61
views
1
answer
asked
Aug 9, 2017
by
anonymous
speed control methods of three phase induction motor?
speed control methods of three phase induction motor?
Last answer:
Speed control of three phase induction motor
speed
control
phase
induction
motor
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191
views
2
answers
asked
Mar 20, 2018
by
anonymous
Which motor has the poorest speed control?
Last answer:
Series motor has the poorest speed control.
motor
poorest
speed
control
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79
views
1
answer
asked
Mar 20, 2018
by
anonymous
For the same H.P. rating and full load speed, following motor has poor starting torque?
Last answer:
For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.
hp
rating
full
load
speed
motor
poor
starting
torque
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114
views
1
answer
asked
Aug 6, 2017
by
anonymous
what is the difference between synchronous and asynchronous motor?
what is the difference between synchronous and asynchronous motor?
Last answer:
Asynchronous motors and syncrouns motor are called as dc machines. and also syncrouns motor called as induction motor. Asynonymous motor as are rotates with constant speed we not able to operate . ... It is able to operate. These are a small difference between syncrouns and asynchronous motors.
synchronous
asynchronous
motor
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237
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2
answers
asked
Apr 28, 2018
by
anonymous
The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and
The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is (A) 0.25 pu (B) 0.5 pu (C) 1.0 pu (D) 1.5 pu
Last answer:
The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and quadrature-axis reactance, 0.5 pu, and input voltage, 1.0 pu is 0.5 pu
maximum
reluctance
power
salient-pole
synchronous
motor
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71
views
1
answer
asked
Mar 20, 2018
by
anonymous
In variable speed motor?
Last answer:
In variable speed motor a weaker commutating field is needed at low speed than at high speed.
variable
speed
motor
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45
views
1
answer
asked
Apr 28, 2018
by
anonymous
A three-phase synchronous motor connected to ac mains is running at full load and unity power factor.
A three-phase synchronous motor connected to ac mains is running at full load and unity power factor. lf its shaft load is reduced by half and field current is held constant then its new power factor will be
Last answer:
Leading
synchronous
motor
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455
views
2
answers
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
views
1
answer
asked
Mar 3, 2018
by
anonymous
In synchronous motor, does the winding losses vary with load?
In synchronous motor, does the winding losses vary with load?
Last answer:
No, in the synchronous motor the winding losses do not vary with load.
synchronous
motor
winding
losses
vary
load
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492
views
1
answer
asked
May 8, 2018
by
anonymous
Damper winding in a synchronous motor
Damper winding in a synchronous motor
Last answer:
Damper winding in a synchronous motor Serves to start the motor.
damper
winding
synchronous
motor
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58
views
1
answer
asked
Mar 15, 2018
by
anonymous
How can we improve power factor using synchronous motor?
How can we improve power factor using synchronous motor?
improve
power
factor
synchronous
motor
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60
views
0
answers
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
views
1
answer
asked
Mar 20, 2018
by
anonymous
The speed of a universal motor is generally reduced by using?
Last answer:
The speed of a universal motor is generally reduced by using gear trains.
speed
universal
motor
reduced
using
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69
views
1
answer
asked
Oct 13, 2019
by
anonymous
Speed control of the motor using TRIAC
Speed control of the motor using TRIAC
Last answer:
Speed control of the motor using TRIAC: This basic phase triggering circuit uses the triac in series with the motor across an AC sinusoidal supply. The variable resistor, VR1 is used ... meaning that it may not trigger at the exact same point for each positive and negative half cycle.
speed
control
motor
triac
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208
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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
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122
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1
answer
asked
Mar 15, 2018
by
anonymous
How do you measure the speed of a motor?
How do you measure the speed of a motor?
measure
speed
motor
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36
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0
answers
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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173
views
1
answer
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
views
1
answer
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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116
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1
answer
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
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1
answer
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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735
views
1
answer
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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80
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1
answer
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