The effect of increasing load on a synchronous motor running with normal excitation is

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.
by

1 Answer

Answer :

The effect of increasing load on a synchronous motor running with normal excitation is Increase Ia, but decrease power factor


by

Related questions

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.

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 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.

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.

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.

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.

In synchronous motor, does the winding losses vary with load?

Description : 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.

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 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.

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 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.

While keeping the excitation constant, if the steam supply of an alternator running in parallel with another

Description : 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

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.

For a D.C. shunt motor if the excitation is changed?

Last Answer : For a D.C. shunt motor if the excitation is changed torque will change but power will remain constant.

A three-phase synchronous motor connected to ac mains is running at full load and unity power factor.

Description : 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

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

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.

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.

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

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.

what is the difference between synchronous and asynchronous motor?

Description : what is the difference between synchronous and asynchronous motor?

Last Answer : Asynchronous motors and syncrouns motor are called as dc machines.  and also syncrouns motor called as induction motor. Asynonymous motor as are rotates with constant speed we not able to operate . ... It is able to operate. These are a small difference between syncrouns and asynchronous motors. 

A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s.

Description : A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be

Last Answer : A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be 474 V

As the load is increased the speed of D.C. shunt motor will?

Last Answer : As the load is increased the speed of D.C. shunt motor will reduce slightly.

For the same H.P. rating and full load speed, following motor has poor starting torque?

Last Answer : For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.

The speed/load characteristics of a universal motor is same as that of?

Last Answer : The speed/load characteristics of a universal motor is same as that of D.C. series motor.

A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance

Description : A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is

Last Answer : A 200 V dc shunt motor is running at 1000 rpm and drawing a current of 10 A. Its armature winding resistance is 2 Ohm. It. is braked by plugging. The resistance to be connected in series with armature to restrict armature current to 10 A, is 36 Ohm

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

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

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.

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.

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 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 armature current of the synchronous motor?

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

An over excited synchronous motor on noload is known as?

Last Answer : An over excited synchronous motor on noload is known as synchronous condenser.

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.

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.

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.