The operating speed of a synchronous motor can be changed to new fixed value by?

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1 Answer

Answer :

The operating speed of a synchronous motor can be changed to new fixed value by changing frequency.

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Related questions

In a synchronous generator if the excitation increased from a low value to normal value, with a fixed load

Description : 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

If we change the excitation of synchronous machine will it affect on motor speed?

Description : 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.

Synchronous motor always runs at which speed?

Description : Synchronous motor always runs at which speed?

Last Answer : Synchronous motor always runs at synchronous speed.

The no-load speed of a single-phase SCR bridge converter fed separately excited dc motor operating at a

Description : 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) ... 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

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.

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.

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.

The synchronous speed of an 8 pole induction motor supplied power from a 50 Hz source will be ?

Description : 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

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.

What is the maximum value of torque angle in synchronous motor?

Description : 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.

Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power

Description : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, ... system frequency is (A) 50 Hz (B) 51 Hz (C) 51.25 Hz (D) 51.5 Hz

Last Answer : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency is 50 Hz

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%.

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.

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.

A synchronous motor can develop synchronous torque?

Last Answer : A synchronous motor can develop synchronous torque at synchronous speed.

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.

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.

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.

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.

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 construction of a synchronous motor resembles?

Last Answer : The construction of a synchronous motor resembles an alternator.

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.

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.

The armature current of the synchronous motor?

Last Answer : The armature current of the synchronous motor has large values for low and high excitation.

Which motor have more efficiency, synchronous motor or induction motor?

Description : Which motor have more efficiency, synchronous motor or induction motor?

Last Answer : Synchronous motor has more efficiency.

How can we reverse the direction of rotation of synchronous motor?

Description : 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.

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.

Hunting in synchronous motor cannot be due to?

Description : Hunting in synchronous motor cannot be due to?

Last Answer : Hunting in synchronous motor cannot be due to windage friction.

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.

The damping winding in synchronous motor is generally used to?

Description : 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.

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.

An unexcited single phase synchronous motor is ?

Description : An unexcited single phase synchronous motor is ?

Last Answer : An unexcited single-phase synchronous motor is reluctance motor.

A synchronous motor can be made self starting by providing?

Description : A synchronous motor can be made self starting by providing?

Last Answer : A synchronous motor can be made self-starting by providing damper bar.

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.

The back emf of synchronous motor depends on?

Description : The back emf of synchronous motor depends on?

Last Answer : The back emf of synchronous motor depends on load angle.

Can we use the synchronous motor as the synchronous capacitor?

Description : 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.

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.

what will happen when excitation of an unloaded salient pole synchronous motor suddenly gets disconnected?

Description : 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.

Three phase synchronous motor will have how many sliprings?

Description : Three phase synchronous motor will have how many sliprings?

Last Answer : Three phase synchronous motor will have two sliprings.

The relay operating speed depends upon?

Last Answer : The relay operating speed depends upon the spring tension, the rate of flux built up, armature core air gap.

An electric motor in which both stator field and rotor rotates with same speed is called?

Description : 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.

In a single-phase induction motor, the operating direction is determined by the ________

Description : In a single-phase induction motor, the operating direction is determined by the ________ A) Rotor B) Stator C) Starting circuit D) None of these

Last Answer : In a single-phase induction motor, the operating direction is determined by the Starting circuit

List different starting methods of three phase synchronous motor. Explain any one of them.

Description : 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. 

Draw and explain V and inverted V curves for synchronous motor.

Description : 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.

List different torques in synchronous motor.

Description : 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

Damper winding in a synchronous motor

Description : Damper winding in a synchronous motor

Last Answer : Damper winding in a synchronous motor Serves to start the motor.

In a self-controlled synchronous motor fed from a variable frequency inverter

Description : 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

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