Centrifugal switch disconnects the auxiliary winding of the motor at about what percent of synchronous speed?

by

1 Answer

Answer :

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

by

Related questions

A centrifugal switch is used to disconnect starting winding when motor has?

Last Answer : A centrifugal switch is used to disconnect starting winding when motor has picked up about 50 to 70 per cent of rated speed.

If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open then?

Last Answer : If the centrifugal switch of a two-value capacitor motor using two capacitors fails to open then Electrolytic capacitor will, in all probability, suffer break down.

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.

In split-phase motor auxiliary winding is of?

Last Answer : In split-phase motor auxiliary winding is of thin wire placed at the top of the slots.

In a single phase motor the centrifugal switch?

Last Answer : In a single phase motor the centrifugal switch disconnects auxiliary winding of the 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.

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.

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 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.

In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to?

Last Answer : In a capacitor start and run motors the function of the running capacitor in series with the auxiliary winding is to improve power factor.

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.

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.

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 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

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

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

The starting winding of a single-phase motor is placed in?

Last Answer : The starting winding of a single-phase motor is placed in stator.

If starting winding of a single-phase induction motor is left in the circuit, it will?

Last Answer : If starting winding of a single-phase induction motor is left in the circuit, it will draw excessive current and overheat.

Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a?

Last Answer : Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a magnetic relay.

The purpose of stator winding in the compensated repulsion motor is to?

Last Answer : The purpose of stator winding in the compensated repulsion motor is to improve power factor and provide better speed regulation.

In split phase motor main winding is of?

Last Answer : In split phase motor main winding is of thick wire placed at the bottom of the slots.

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

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

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

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

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.

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. 

In A.C. series motor compensating winding is employed to?

Last Answer : In A.C. series motor compensating winding is employed to reduce sparking at the brushes.

The running winding of a single phase motor on testing with meggar is found to be ground...

Description : The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be?

Last Answer : The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be at the slot edge where coil enters or comes out of the slot.

In a capacitor start motor, the phase displacement between starting and running winding can be nearly?

Last Answer : In a capacitor start motor, the phase displacement between starting and running winding can be nearly 90°.

In a split phase motor, the running winding should have?

Last Answer : In a split phase motor, the running winding should have low resistance and high inductance.

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

The speed of a three-phase induction motor is controlled by variable voltage variable frequency control

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 

The speed of a 2-pole, 3-phase stepper motor operated by 1200 pulses/min

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

In variable speed motor?

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

Which motor has the poorest speed control?

Last Answer : Series motor has the poorest speed control.

The speed of a D.C. motor can be controlled by varying

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

The speed of a D.C. shunt motor can be increased by?

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

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 of a D.C. series motor is?

Last Answer : The speed of a D.C. series motor is inversely proportional to the armature current.

In a D.C. shunt motor, speed is?

Last Answer : In a D.C. shunt motor, speed is independent of armature current.

The speed of a universal motor is usually reduced by using?

Last Answer : The speed of a universal motor is usually reduced by using gearing.

Speed control of a universal motor is achieved by?

Last Answer : Speed control of a universal motor is achieved by varying field flux with tapped field windings, connecting rheostat in series, applying variable voltage by means of silicon controlled rectifier, applying variable voltage by means of variable auto-transformer.

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.

Speed torque characteristic of a repulsion induction motor is similar to that of a D.C.?

Last Answer : Speed torque characteristic of a repulsion induction motor is similar to that of a D.C. compound motor.

The speed control of universal motor used for sewing machines is by?

Last Answer : The speed control of universal motor used for sewing machines is by varying the resistance.

What are the speed control methods of dc motor?

Description : What are the speed control methods of dc motor?

Last Answer : Field control of DC motor Armature control of DC motor

speed control methods of three phase induction motor?

Description : speed control methods of three phase induction motor?

Last Answer : Speed control of three phase induction motor

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.