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
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Apr 28, 2018
by
anonymous

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 ... 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
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130 views
1 answer
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Apr 29, 2018
by
anonymous

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.
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116 views
1 answer
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Mar 20, 2018
by
anonymous

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.
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105 views
1 answer
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Mar 18, 2018
by
anonymous

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.
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367 views
1 answer
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Mar 18, 2018
by
anonymous

Last Answer : Yes, we can make the power factor of synchronous motor leading by adjusting its excitation.
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109 views
1 answer
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Mar 6, 2018
by
anonymous

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.
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302 views
1 answer
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Mar 20, 2018
by
anonymous

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.
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218 views
1 answer
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Mar 20, 2018
by
anonymous

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.
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150 views
1 answer
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Mar 18, 2018
by
anonymous

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.
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162 views
1 answer
asked
Mar 18, 2018
by
anonymous

In a synchronous motor which losses varies with load?
Last Answer : In a synchronous motor, copper losses varies with load.
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102 views
1 answer
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Mar 18, 2018
by
anonymous

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.
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223 views
1 answer
asked
Mar 18, 2018
by
anonymous

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.
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123 views
1 answer
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Mar 18, 2018
by
anonymous

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.
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512 views
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Mar 3, 2018
by
anonymous

While keeping the excitation constant, if the steam supply of an alternator running in parallel with another identical alternator is increased, then (A) It would over-run the other alternator (B) Its rotor ... (C) Its portion of share in load will increase (D) Its power factor would be decreased.
Last Answer : While keeping the excitation constant, if the steam supply of an alternator running in parallel with another identical alternator is increased, then Its portion of share in load will increase
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430 views
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Apr 28, 2018
by
anonymous

Last Answer : The size of a synchronous motor decreases with the increase in flux density.
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196 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : For a D.C. shunt motor if the excitation is changed torque will change but power will remain constant.
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168 views
1 answer
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Mar 20, 2018
by
anonymous
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Last Answer : Slip-rings in a synchronous motor carry direct current.
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1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The efficiency of a properly designed synchronous motor will usually fall in range 85 to 95%.
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1 answer
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Mar 20, 2018
by
anonymous

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.
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169 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The operating speed of a synchronous motor can be changed to new fixed value by changing frequency.
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121 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : A synchronous motor can develop synchronous torque at synchronous speed.
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1 answer
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Mar 20, 2018
by
anonymous

Last Answer : In case one phase of a three-phase synchronous motor is short-circuited the motor will not start.
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254 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a synchronous motor, the armature current has large values for high and low excitation.
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138 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The duration of sudden short-circuit test on a synchronous motor is usually about one second.
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150 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The construction of a synchronous motor resembles an alternator.
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83 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.
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257 views
1 answer
asked
Mar 20, 2018
by
anonymous

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?
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106 views
0 answers
asked
Mar 20, 2018
by
anonymous

Last Answer : The armature current of the synchronous motor has large values for low and high excitation.
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107 views
1 answer
asked
Mar 20, 2018
by
anonymous

Which motor have more efficiency, synchronous motor or induction motor?
Last Answer : Synchronous motor has more efficiency.
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93 views
1 answer
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Mar 18, 2018
by
anonymous

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.
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305 views
1 answer
asked
Mar 18, 2018
by
anonymous

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.
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1 answer
asked
Mar 18, 2018
by
anonymous

Hunting in synchronous motor cannot be due to?
Last Answer : Hunting in synchronous motor cannot be due to windage friction.
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96 views
1 answer
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Mar 18, 2018
by
anonymous

The damping winding in synchronous motor is generally used to?
Last Answer : The damping winding in synchronous motor is generally used to provide starting torque and prevent hunting.
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157 views
1 answer
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Mar 18, 2018
by
anonymous

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.
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483 views
1 answer
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Mar 18, 2018
by
anonymous

An unexcited single phase synchronous motor is ?
Last Answer : An unexcited single-phase synchronous motor is reluctance motor.
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160 views
1 answer
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Mar 18, 2018
by
anonymous

A synchronous motor can be made self starting by providing?
Last Answer : A synchronous motor can be made self-starting by providing damper bar.
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131 views
1 answer
asked
Mar 18, 2018
by
anonymous
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The back emf of synchronous motor depends on?
Last Answer : The back emf of synchronous motor depends on load angle.
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65 views
1 answer
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Mar 18, 2018
by
anonymous

Synchronous motor always runs at which speed?
Last Answer : Synchronous motor always runs at synchronous speed.
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90 views
1 answer
asked
Mar 18, 2018
by
anonymous

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.
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91 views
1 answer
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Mar 18, 2018
by
anonymous

Three phase synchronous motor will have how many sliprings?
Last Answer : Three phase synchronous motor will have two sliprings.
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1 answer
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Mar 18, 2018
by
anonymous

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
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564 views
2 answers
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Apr 28, 2018
by
anonymous
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In a synchronous generator delivering lagging power factor load (1) the excitation emf leads terminal voltage by the power angle (2) the excitation emf lags terminal voltage by the power angle (3) ... by the power factor angle (4) excitation emf lags the terminal voltage by the power factor angle
Last Answer : In a synchronous generator delivering lagging power factor load the excitation emf leads terminal voltage by the power angle
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340 views
1 answer
asked
Apr 29, 2018
by
anonymous

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.
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111 views
1 answer
asked
Mar 20, 2018
by
anonymous

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.
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2.7k views
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Jul 5, 2019
by
anonymous

List different starting methods of three phase synchronous motor. Explain any one of them.
Last Answer : Different Starting Methods of Three Phase Synchronous Motor: As synchronous motor is not self starting, different methods of starting are as follows: 1) By using an Induction (Pony) motor 2) ... . The rotor gets pulled into synchronism and starts running at constant speed as a synchronous motor.
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157 views
1 answer
asked
May 7, 2020
by
anonymous

Draw and explain V and inverted V curves for synchronous motor.
Last Answer : V curves' and inverted V curves' for Synchronous Motor: V curve: V curve is a plot of the stator current versus field current for different constant loads. The graph is plotted ... Vcurves of synchronous motor. The highest point on each of these curves indicates unity power factor.
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498 views
1 answer
asked
May 7, 2020
by
anonymous

List different torques in synchronous motor.
Last Answer : Different Torques in Synchronous Motor: 1) Starting torque 2) Running torque 3) Pull-in torque 4) Pull-out torque
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115 views
1 answer
asked
May 7, 2020
by
anonymous

Damper winding in a synchronous motor
Last Answer : Damper winding in a synchronous motor Serves to start the motor.
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87 views
1 answer
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May 8, 2018
by
anonymous

In a self-controlled synchronous motor fed from a variable frequency inverter (1) the rotor poles invariably have damper windings (2) there are stability problems (3) the speed of the rotor decides stator frequency (4) the frequency of the stator decides the rotor speed
Last Answer : 2
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636 views
2 answers
asked
Apr 29, 2018
by
anonymous
