1 Answer

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.

Related questions

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

Last Answer : Centrifugal switch disconnects the auxiliary winding of the motor at about 70 to 80 percent of synchronous speed.

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.

Description : Why the speed of synchronous motor is constant?

Description : Reluctance motor

Last Answer : Reluctance motor Reluctance is opposition to magnetic flux. Reluctance is analogous to electric resistance. Reluctance motor does not have any winding on rotor. Rotor consists of  ... for rotation of rotor is generated through magnetic reluctance so it called reluctance motor.

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

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.

Description : Synchronous motor always runs at which speed?

Last Answer : Synchronous motor always runs at synchronous speed.

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

Description : Why synchronous motor Cannot start itself?

Description : 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

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

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.

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

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.

Description : Damper winding in a synchronous motor

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

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

Description : What is the principle of synchronous motor?

Description : What is the use of synchronous motor?

Last Answer : Yes, we can make the power factor of synchronous motor leading by adjusting its excitation.

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. 

Last Answer : The speed of a D.C. shunt motor can be increased by increasing the resistance in field circuit.

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

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

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

Description : Hunting in synchronous motor cannot be due to?

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

Last Answer : A synchronous motor running with normal excitation adjusts to load increases essentially by increase in armature current.

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.

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.

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.

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.

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

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

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.

Last Answer : In case one phase of a three-phase synchronous motor is short-circuited the motor will not start.

Description : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque  (1) Decreases (2) Increases (3) Remains constant (4) None of the above

Last Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases 

Description : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min (A) 100 rpm (B) 200 rpm (C) 400 rpm (D) 800 rpm

Last Answer : The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min 200 rpm

Last Answer : In variable speed motor a weaker commutating field is needed at low speed than at high speed.

Last Answer : Series motor has the poorest speed control.

Description : The speed of a D.C. motor can be controlled by varying  1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above

Last Answer : The speed of a D.C. motor can be controlled by varying  1. Its flux per pole 2. Resistance of armature circuit 3. Applied voltage 4. All of the above