The standard full-load power factor ratings for synchronous motors are?

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1 Answer

Answer :

The standard full-load power factor ratings for synchronous motors are unity or 0.8 leading.

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Related questions

For power factor correction, synchronous motors operate at?

Last Answer : For power factor correction, synchronous motors operate at no-load and greatly over-excited fields.

If the load of the normally excited synchronous motor is increased the power factor will?

Description : 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.

The synchronous motor which works on leading power factor and does not drive any mechanical load is called?

Description : 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.

A synchronous motor has better power factor as compared to that of an equivalent induction motor...

Description : 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.

If we change the excitation of synchronous machine will it affect on power factor?

Description : 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.

If the field of synchronous motor is under excited, power factor will be?

Description : 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.

Synchronous motors are generally not self-starting because?

Last Answer : Synchronous motors are generally not self-starting because the direction of instantaneous torque reverses after half cycle.

In a synchronous generator delivering lagging power factor load

Description : 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

The power factor angle and torque angle of a salient pole synchronous generator drawing a current of 1.0 pu

Description : 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

In a distribution system, in order to improve power factor, the synchronous capacitors are installed?

Last Answer : In a distribution system, in order to improve power factor, the synchronous capacitors are installed at the receiving end.

Can a synchronous condenser improve power factor?

Description : Can a synchronous condenser improve power factor?

Last Answer : Yes, synchronous condenser can improve power factor.

How can we improve power factor using synchronous motor?

Description : How can we improve power factor using synchronous motor?

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.

SYNCHRONOUS MOTORS MCQ

Description : SYNCHRONOUS MOTORS MCQ

Last Answer : 101. In a synchronous motor it the back e.m.f. generated in the armature at noload is approximately equal to the applied voltage, then (a) the motor is said to be fully loaded (b) the torque ... square of the applied voltage (c) inversely proportional to applied voltage (d) none of the above Ans: a

Damper winding is provided in 3 phase synchronous motors to :

Description : Damper winding is provided in 3 phase synchronous motors to :

Last Answer : Damper winding is provided in 3 phase synchronous motors to : provide starting torque and prevent hunting

What is the difference between synchronous and asynchronous motors?

Description : What is the difference between synchronous and asynchronous motors?

Last Answer : The motor which rotates at constant speed is called synchronous motor. And that constant speed is called as synchronous speed.  And the motor which does not rotates at constant speed are called asynchronous motor. Asynchronous motor is also called as Induction motor.

The synchronous motor will develop maximum power when the load angle is?

Description : 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.

Synchronsizing power of a synchronous machine is?

Last Answer : Synchronsizing power of a synchronous machine is inversely proportional to the synchronous reactance.

A 50 Hz, 3-phase induction motor delivers a full load speed of 1440 r.p.m. The number of poles of the motor will be

Description : A 50 Hz, 3-phase induction motor delivers a full load speed of 1440 r.p.m. The number of poles of the motor will be

The efficiencies of transformers compared with that of electric motors of the same power are?

Description : The efficiencies of transformers compared with that of electric motors of the same power are?

Last Answer : Transformers have high efficiency than the same ratted motors

Have you ever taken part in surveys about listening/watching ratings?

Description : Have you ever taken part in surveys about listening/watching ratings?

Last Answer : answer:Nielsen Ratings are widely used. They use different methods to see what a group of selected viewers are watching and use that as a sample group. ---------- Nielsen television ratings are ... identify it. That way they can tell more reliably if someone is watching a recorded program as well.

Oil Filter Ratings

Description : Oil Filter Ratings

Last Answer : When grading oil filters, three main criteria must be considered: single-pass efficiency, multiple-pass efficiency, and the micron rating for particle pass-through. Single-Pass Efficiency Single- ... using an ISO approved particle counting is used to determine the real efficiency of oil filters.

The maximum reluctance power of a salient-pole synchronous motor having direct-axis reactance, 1.0 pu and

Description : 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

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.

The maximum constant load torque under which a synchronous motor will pull into synchronism...

Description : 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.

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.

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.

In a synchronous motor which losses varies with load?

Description : In a synchronous motor which losses varies with load?

Last Answer : In a synchronous motor, copper losses varies with load.

A transformer has negative voltage regulation when its load power factor is

Description : A transformer has negative voltage regulation when its load power factor is   (1) Zero (2) Unity (3) Leading (4) Lagging

Last Answer : 0

Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW

Description : 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

The power factor of a single phase load can be calculated if the instruments available are?

Last Answer : The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.

Load factor of a power station is generally?

Last Answer : Load factor of a power station is generally less than unity.

Load factor of a power station is defined as?

Last Answer : Load factor of a power station is defined as average load/maximum demand.

Minimum voltage regulation occurs when the power factor of the load is?

Description : 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.

Why the power factor of semiconverter is better than full converter?

Description : Why the power factor of semiconverter is better than full converter?

Last Answer : Power factor of semiconverter is better than full converter

At full -load of a transformer, the iron loss and copper loss are 3000 W and 4000 W respectively. Then total

Description : At full -load of a transformer, the iron loss and copper loss are 3000 W and 4000 W respectively. Then total loss at maximum efficiency is :  (A) 7000 W (B) 6000 W (C) 8000 W (D) 4000 W

Last Answer : At full -load of a transformer, the iron loss and copper loss are 3000 W and 4000 W respectively. Then total loss at maximum efficiency is : 6000 W

The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to :

Description : The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to :

Last Answer : The ratio of full -load volt-amperes to short-circuit volt-amperes is equal to : Z (p.u)

The ratio of starting torque to full-load torque is least in case of?

Last Answer : The ratio of starting torque to full-load torque is least in case of shunt motors.

Slip-rings in a synchronous motor carry?

Last Answer : Slip-rings in a synchronous motor carry direct current.

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%.