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

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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.

Answer : In a A.C. series motor armature coils are usually connected to commutator through resistance.

Answer : A.C. series motor as compared to D.C. series motor has smaller brush width, less number of field turns, more number of armature turns, less air gap.

Description : State the modification to be done in dc series motor to work satisfactorily as ac series motor. State applications of ac series motor.

Answer : Modifications are necessary in a dc series motor so that it operates satisfactorily on ac supply. The modifications are as follows:  1) AC series motor is built with a few field turns as ... and grinders 5) High speed vacuum cleaners 6) Sewing machines 7) Food processors 8) Drilling machine 

Answer : If a D.C. series motor is operated on A.C. supply, it will spark excessively, have poor efficiency, have poor power factor.

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?

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.

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

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

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

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

Answer : When a D.C. series motor is connected to A.C. supply, the power factor will be low because of high inductance of field and armature circuits.

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

Description : The damping winding in synchronous motor is generally used to?

Answer : The damping winding in synchronous motor is generally used to provide starting torque and prevent hunting.

Description : In case of conductively compensated D.C. series motors, the compensating winding is provided?

Answer : In case of conductively compensated D.C. series motors, the compensating winding is provided in series with armature winding.

Description : Damper winding in a synchronous motor

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

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

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

Answer : No, in the synchronous motor the winding losses do not vary with load.

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

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

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

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

Answer : If the field winding of an unloaded salient pole synchronous motor is open circuited, the motor will stop.

Answer : In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to 25% of the previous value.

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Description : Write two applications of D.C. series motor. 

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Answer : A D.C. series motor is that which has its field winding consisting of thick wire and less turns.

Answer : The direction of rotation of a D.C. series motor can be changed by interchanging field terminals.

Answer : In a low power factor wattmeter the compensating coil is connected in series with pressure coil.

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Answer : .embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; max-width: 100%; } .embed-container iframe, .embed-container object, .embed-container embed { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }

Description : Describe the reason of using dc series motor for electric trains.

Answer : Electric trains require an inverse torque speed characteristics for proper operation. That is a higher torque is required at start (when speed is nil or low) and as the train picks up ... torque - speed characteristics of DC series motors match, these motors are suitable for electric trains

Description : What are the advantages of DC series motor?

Description : Why dc series motor should not be started at no load?

Description : Why a dc series motor has a high starting torque?

Description : Explain series switching control of AC load. Single phase resistance load - Integral half cycle control Phase control - Resistance load

Description : Explain magnetic effect employed in measuring instrument.

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Description : List any four effects employed in measuring instruments.

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Description : Reflector mirrors employed for exploiting solar energy are called the  (1) Mantle (2) Heliostats (3) Diffusers (4) Ponds

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Description : The direction of rotation of an inverter fed 3-phase ac motor is reversed by (A) a mechanical reversing switch (B) reversing the input dc link voltage (C) operating the inverter as a rectifier (D) changing the sequence of switching

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Description : What are the parts of AC motor?

Description : What is the principle of AC motor?

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Description : AC motor

Answer : AC motor AC motor have two types one is Induction motor and second is synchronous motor. Induction motor have two types one is single phase induction motor and second is three phase ... self starting motor so using  external motor or we have to start it as induction motor.

Answer : In case of D.C. machine winding, number of commutator segments is equal to number of armature coils.

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Answer : In D.C. machines fractional pitch winding is used to reduce the sparking.

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