Exciters of synchronous machines are?

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1 Answer

Answer :

Exciters of synchronous machines are d.c. shunt machines.

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Related questions

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.

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

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

Synchronsizing power of a synchronous machine is?

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

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.

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.

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 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.

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.

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.

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.

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.

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 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.

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.

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.

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.

V - curve of synchronous machine shows the relation between?

Description : V - curve of synchronous machine shows the relation between?

Last Answer : V - curve of synchronous machine shows the relation between AC armature current and DC field current.

Why synchronous machine is called doubly excited machine?

Description : Why synchronous machine is called doubly excited machine?

Last Answer : Armature windings of synchronous machines either deliver 3 phase AC or absorb 3 phase AC source,  whereas field windings are energized from DC source. Thus due to presence of AC on armature and DC on field windings, synchronous machines are often referred as doubly excited machines.

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.

Which machine is the exciter of synchronous machine?

Description : Which machine is the exciter of synchronous machine?

Last Answer : DC shunt machine is the exciter of synchronous machine.

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.

Synchronous motor always runs at which speed?

Description : Synchronous motor always runs at which speed?

Last Answer : Synchronous motor always runs at synchronous speed.

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.

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