Last Answer : Yes, we can make the power factor of synchronous motor leading by adjusting its excitation.
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110 views
1 answer
asked
Mar 6, 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
asked
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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226 views
1 answer
asked
Mar 18, 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
asked
Mar 20, 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
asked
Mar 18, 2018
by
anonymous

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

How can we improve power factor using synchronous motor?
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78 views
0 answers
asked
Mar 15, 2018
by
anonymous

Last Answer : A synchronous motor running with normal excitation adjusts to load increases essentially by increase in armature current.
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196 views
1 answer
asked
Mar 20, 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
asked
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
asked
Mar 20, 2018
by
anonymous
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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
asked
Mar 20, 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
asked
Mar 18, 2018
by
anonymous

Last Answer : The standard full-load power factor ratings for synchronous motors are unity or 0.8 leading.
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98 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : For power factor correction, synchronous motors operate at no-load and greatly over-excited fields.
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110 views
1 answer
asked
Mar 20, 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
asked
Mar 18, 2018
by
anonymous

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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550 views
1 answer
asked
Apr 28, 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
1 answer
asked
Mar 3, 2018
by
anonymous

In a d.c. motor, the mechanical output power actually comes from?
Last Answer : In a d.c. motor, the mechanical output power actually comes from electrical input power.
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1.2k views
1 answer
asked
Mar 26, 2018
by
anonymous
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The mechanical power developed by the armature of a d.c. motor is equal to?
Last Answer : The mechanical power developed by the armature of a d.c. motor is equal to armature current multiplied by back e.m.f.
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985 views
1 answer
asked
Mar 26, 2018
by
anonymous

Last Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.
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324 views
1 answer
asked
Mar 20, 2018
by
anonymous

The power factor angle and torque angle of a salient pole synchronous generator drawing a current of 1.0 pu from a lagging load are 45o and 15o, respectively. The direct axis and quadrature axis currents, respectively, are (A) 0.5 pu ... pu, 0.5 pu (C) 0.707 pu, 0.707 pu (D) 0.5 pu, 0.5 pu
Last Answer : The power factor angle and torque angle of a salient pole synchronous generator drawing a current of 1.0 pu from a lagging load are 45o and 15o, respectively. The direct axis and quadrature axis currents, respectively, are 0.866 pu, 0.5 pu
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98 views
1 answer
asked
Apr 28, 2018
by
anonymous

Last Answer : In a distribution system, in order to improve power factor, the synchronous capacitors are installed at the receiving end.
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185 views
1 answer
asked
Mar 20, 2018
by
anonymous

Can a synchronous condenser improve power factor?
Last Answer : Yes, synchronous condenser can improve power factor.
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90 views
1 answer
asked
Mar 19, 2018
by
anonymous

A transformer has negative voltage regulation when its load power factor is (1) Zero (2) Unity (3) Leading (4) Lagging
Last Answer : 0
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5.1k views
3 answers
asked
Apr 30, 2018
by
anonymous

Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW then annual energy production is (1) 122.8 GWh (2) 198.55 GWh (3) 128.2 GWh (4) 188.82 GWh
Last Answer : Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW then annual energy production is 122.8 GWh
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148 views
1 answer
asked
Apr 29, 2018
by
anonymous

Last Answer : The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.
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296 views
2 answers
asked
Mar 21, 2018
by
anonymous

Last Answer : Load factor of a power station is generally less than unity.
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107 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Load factor of a power station is defined as average load/maximum demand.
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321 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Minimum voltage regulation occurs when the power factor of the load is?
Last Answer : Minimum voltage regulation occurs when the power factor of the load is leading.
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224 views
1 answer
asked
Mar 19, 2018
by
anonymous

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
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98 views
1 answer
asked
Apr 28, 2018
by
anonymous
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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.
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119 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : The power factor of a single-phase induction motor is usually lagging.
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191 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : An induction motor has relatively high power factor at near full load.
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92 views
1 answer
asked
Mar 20, 2018
by
anonymous

At which time power factor of the induction motor is low?
Last Answer : The power factor of the inducction motor is low at the time of starting as compare to while the induction motor is running.
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151 views
1 answer
asked
Mar 3, 2018
by
anonymous

Last Answer : Slip-rings in a synchronous motor carry direct current.
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99 views
1 answer
asked
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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73 views
1 answer
asked
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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122 views
1 answer
asked
Mar 20, 2018
by
anonymous

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

Last Answer : The construction of a synchronous motor resembles an alternator.
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83 views
1 answer
asked
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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258 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
asked
Mar 18, 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
asked
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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1.5k views
1 answer
asked
Mar 18, 2018
by
anonymous
