The synchronous motor can be used as a capacitor

The synchronous motor can be used as a capacitor

• By increasing excitation

• By decreasing excitation

• By increasing speed

• By decreasing speed
by

1 Answer

Answer :

The synchronous motor can be used as a capacitor By increasing excitation

by

Related questions

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.

A synchronous capacitor is

Description : A synchronous capacitor is (A) an unloaded and under excited 3-phase synchronous motor (B) a loaded and over excited 3-phase synchronous generator (C) an unloaded and over excited 3-phase synchronous motor (D) a 3-phase synchronous generator loaded with a capacitor bank

Last Answer : A synchronous capacitor is an unloaded and over excited 3-phase synchronous motor

A stand alone engine driven synchronous generator is feeding a partly inductive load. A capacitor is now

Description : A stand alone engine driven synchronous generator is feeding a partly inductive load. A capacitor is now connected across the load to completely nullify the inductive current. For this operating condition.  ... left unaltered (D) the field current has to be reduced and fuel input left unaltered

Last Answer : A stand alone engine driven synchronous generator is feeding a partly inductive load. A capacitor is now connected across the load to completely nullify the inductive current. For this operating condition.  the field current has to be reduced and fuel input left unaltered

What will happen if the induction motor runs at synchronous speed ?

Description : What will happen if the induction motor runs at synchronous speed ?

Last Answer : Since there is always slip present in rotor it cannot run at synchronous speed no current will be developed hence no torque will developed

A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously

Description : A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously increased  1. The power factor decreases upto a certain value of field current and thereafter it increases.  2. The armature current ... the correct answer is (a) 1, 2 (b) 3, 4 (c) 1, 3 (d) 2, 4

Last Answer : A synchronous motor operates at 0.8 pf lagging. If the field current of the motor is continuously increased  1. The power factor decreases upto a certain value of field current and thereafter it increases.  2. The armature current ... the correct answer is (a) 1, 2 (b) 3, 4 (c) 1, 3 (d) 2, 4

The maximum possible power of a 3-phase synchronous motor with synchronous reactance 0.8 p.u. connected

Description : The maximum possible power of a 3-phase synchronous motor with synchronous reactance 0.8 p.u. connected to a bus-bar of 1.0 p.u. and excitation adjusted to 1.2 p.u. is (A) 0.5 p.u. (B) 0.96 p.u. (C) 1.5 p.u. (D) 1.8 p.u.

Last Answer : The maximum possible power of a 3-phase synchronous motor with synchronous reactance 0.8 p.u. connected to a bus-bar of 1.0 p.u. and excitation adjusted to 1.2 p.u. is 1.5 p.u.

A 12 -pole, 440 V, 50 Hz, 3 -phase synchronous motor takes a line current of 100 A at 0.8 pf leading....

Description : A 12 -pole, 440 V, 50 Hz, 3 -phase synchronous motor takes a line current of 100 A at 0.8 pf leading. Neglecting losses, the torque developed will be

Last Answer : A 12 -pole, 440 V, 50 Hz, 3 -phase synchronous motor takes a line current of 100 A at 0.8 pf leading. Neglecting losses, the torque developed will be 1165 Nm

When a synchronous motor is started, the field winding is initially :

Description :  When a synchronous motor is started, the field winding is initially :  a)excited by a d.c. sources b) short circuited c) open circuited d) none of these

Last Answer :  When a synchronous motor is started, the field winding is initially : short circuited

A synchronous motor is essentially a motor with

Description : A synchronous motor is essentially a motor with   (a) Constant speed (b) Leading power factor (c) Unity power factor (d) Lagging power factor 

Last Answer : a

A 3~phase synchronous motor, connected to infinite bus, is operating at no load at normal excitation. ...

Description : A 3~phase synchronous motor, connected to infinite bus, is operating at no load at normal excitation. The field excitation of the motor is first decreased to zero and then increased in the ... 2) First decrease and then increase, (3) Increases continuously (4) First increase and then decreased

Last Answer : A 3~phase synchronous motor, connected to infinite bus, is operating at no load at normal excitation. The field excitation of the motor is first decreased to zero and then increased in the reverse direction. The armature current of the synchronous motor will: Increases continuously.

In a 3-phase synchronous motor; ...

Description : In a 3-phase synchronous motor;  (A) the speed of the stator MMF is always more than that of the rotor MMF (B) the speed of the stator MMF is always less than that of the rotor MMF (C) the ... that of the rotor MMF is zero (D) the rotor and the stator MMF are stationary with respect to each other

Last Answer : In a 3 -phase synchronous motor:  the rotor and the stator MMF are stationary with respect to each other

What type of excitation is given to the rotor winding of a synchronous motor?

Description : What type of excitation is given to the rotor winding of a synchronous motor?  (A) DC supply at 100 -250 V (B) AC supply at 400 V (C) Revolving field (D) Induction from stator currents 

Last Answer : Dc supply of 100 to 250v is applied on the field circuit to make stable magnetic field which thens follow the rotating magnetic feild of stator or armature circuit.

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

Why is a capacitor used in a single phase motor and not in three phase motor ?

Description : Why is a capacitor used in a single phase motor and not in three phase motor ?

Last Answer : In 1-phase induction motor capacitor work is generate the auxiliary winding current than excite the main winding to rotor starts rotate. After rotor start rotating about 75% of their speed than auxiliary ... emf to start the motor.so,in 3-phase induction motor is self start induction motor.

Explain the working of a single phase capacitor start induction motor.

Description : Explain the working of a single phase capacitor start induction motor. 

Last Answer : Single phase capacitor start induction motor https://youtu.be/31lvvzU5Puc

In the capacitor-start, capacitor-run single-phase induction motor

Description : In the capacitor-start, capacitor-run single-phase induction motor (A) two capacitors are connected across the main winding (B) when the centrifugal switch opens, the permanent capacitor is left ... left in the main winding circuit (D) two capacitors are connected across the auxiliary winding.

Last Answer : In the capacitor-start, capacitor-run single-phase induction motor when the centrifugal switch opens, the permanent capacitor is left in the auxiliary winding circuit

A capacitor start, capacitor run single phase induction motor is basically a : -

Description : A capacitor start, capacitor run single phase induction motor is basically a : -  a) ac series motor b) dc series motor c) 2 phase induction motor d) 3 phase induction motor

Last Answer : A capacitor start, capacitor run single phase induction motor is basically a : -  2 phase induction motor 

In a capacitor start single-phase induction motor, the capacitor is connected in: ...

Description : In a capacitor start single-phase induction motor, the capacitor is connected in:  (A) series with the main winding (B) series with the auxiliary winding (C) series with both the windings (D) parallel with the auxiliary winding .

Last Answer : In a capacitor start single-phase induction motor, the capacitor is connected in: series with the auxiliary winding 

The value of the capacitor in a capacitor start motor controls the__________.

Last Answer : The value of the capacitor in a capacitor start motor controls the starting torque

Synchronous Of the motor Generated Torque What? What ?

Last Answer : 1 / Starting Torque 2 / Running Torque 3 / Pool In Torque 4 / Pool Out Torque

Synchronous Motor What ?

Last Answer : that Motor Synchronous At speed Turn around Him Synchronous Motor Says.

Synchronous Of the motor Torque Angle What ?

Last Answer : synchronous Of the motor Rotor Poll Axis And Stator Poll Axis Of In That Angular Interval Stays Him That said Of the motor Torque Angle Says.

Synchronous Of the motor Most Large Advantage What ?

Last Answer : Load In change Of Of speed No Change Is No.

Synchronous Motor No In principle Work By ?

Last Answer : synchronous Motor Magnetic Inter Locking In principle Work By

A four pole, 60 Hz, three-phase synchronous motor comes up to 1760 RPM when started as an induction motor. What is the percent slip after the rotor field is energized? A. 0 B. 1.1 C. 2.2 D. 3.3

Description : A four pole, 60 Hz, three-phase synchronous motor comes up to 1760 RPM when started as an induction motor. What is the percent slip after the rotor field is energized? A. 0 B. 1.1 C. 2.2 D. 3.3

Last Answer : Answer: A

Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency? A. A four-pole synchronous motor under normal load. B. A four-pole induction motor under no load. C. A six-pole synchronous motor under normal load. D. A six-pole induction motor under full load.

Description : Which of the listed motors will operate at the highest RPM, assuming that each operates at the same frequency? A. A four-pole synchronous motor under normal load. B. A four-pole induction motor under ... A six-pole synchronous motor under normal load. D. A six-pole induction motor under full load.

Last Answer : Answer: A

A four-pole 60-hertz induction motor has a synchronous speed of 1800 RPM and a slip of 4 percent at full load. What will be its full load speed? A. 1728.0 RPM B. 1730.7 RPM C. 1800.0 RPM D. 1872.0 RPM

Description : A four-pole 60-hertz induction motor has a synchronous speed of 1800 RPM and a slip of 4 percent at full load. What will be its full load speed? A. 1728.0 RPM B. 1730.7 RPM C. 1800.0 RPM D. 1872.0 RPM

Last Answer : Answer: A

If the synchronous speed of a 12 pole, polyphase, induction motor operating at 60 Hz were 600 RPM, how many poles will be required in a similar motor operating at the same frequency but having a synchronous speed of 900 RPM? A. 4 B. 6 C. 8 D. 18

Description : If the synchronous speed of a 12 pole, polyphase, induction motor operating at 60 Hz were 600 RPM, how many poles will be required in a similar motor operating at the same frequency but having a synchronous speed of 900 RPM? A. 4 B. 6 C. 8 D. 18

Last Answer : Answer: C

The effect of carrying field excitation excessively high on a synchronous motor will result in a _____________. A. tendency for the motor to fall out of step B. tendency for the motor to overspeed C. tendency for the motor to overheat D. loss of motor speed regulation

Description : The effect of carrying field excitation excessively high on a synchronous motor will result in a _____________. A. tendency for the motor to fall out of step B. tendency for the motor to overspeed C. tendency for the motor to overheat D. loss of motor speed regulation

Last Answer : Answer: C

If a synchronous motor begins to vibrate severely and pull out of synchronism, the cause may be ____________. A. an overload B. an open in the field coils C. no exciter voltage D. all of the above

Description : If a synchronous motor begins to vibrate severely and pull out of synchronism, the cause may be ____________. A. an overload B. an open in the field coils C. no exciter voltage D. all of the above

Last Answer : Answer: D

The speed of a synchronous motor is varied by _____________. A. interchanging any two of the three live leads B. changing the voltage of the system C. changing the input frequency D. increasing the field excitation

Description : The speed of a synchronous motor is varied by _____________. A. interchanging any two of the three live leads B. changing the voltage of the system C. changing the input frequency D. increasing the field excitation

Last Answer : Answer: C

What type of electric motor is commonly used to start small auxiliary diesel engines? A. synchronous B. series C. shunt D. cage

Description : What type of electric motor is commonly used to start small auxiliary diesel engines? A. synchronous B. series C. shunt D. cage

Last Answer : Answer: B

Which of the instruments listed could be use to locate a grounded field coil in a synchronous motor? A. Ammeter B. Voltmeter C. Megohmmeter D. Frequency meter

Description : Which of the instruments listed could be use to locate a grounded field coil in a synchronous motor? A. Ammeter B. Voltmeter C. Megohmmeter D. Frequency meter

Last Answer : Answer: C

The direction of propeller shaft rotation in a turbo-electric synchronous propulsion drive motor is changed by reversing the _____________. A. polarity of the propulsion motor B. polarity of the propulsion generator C. phase sequence of power to the motor D. phase sequence of power to the generator

Description : The direction of propeller shaft rotation in a turbo-electric synchronous propulsion drive motor is changed by reversing the _____________. A. polarity of the propulsion motor B. polarity of the propulsion generator C. phase sequence of power to the motor D. phase sequence of power to the generator

Last Answer : Answer: C

The propeller shaft speed in a turbo-electric, synchronous, propulsion drive motor is changed by varying the __________. A. turbine speed B. number of motor poles C. field strength of the generator D. field strength of the motor

Description : The propeller shaft speed in a turbo-electric, synchronous, propulsion drive motor is changed by varying the __________. A. turbine speed B. number of motor poles C. field strength of the generator D. field strength of the motor

Last Answer : Answer: A

If an induction motor were to be operated at 90% rated voltage, _____________. A. there would be an increase in starting torque B. starting current would increase slightly C. synchronous speed would decrease slightly D. the slip would increase

Description : If an induction motor were to be operated at 90% rated voltage, _____________. A. there would be an increase in starting torque B. starting current would increase slightly C. synchronous speed would decrease slightly D. the slip would increase

Last Answer : Answer: D

The speed of a wound-rotor induction motor _____________. A. will be fixed by the number of field poles B. can be varied by a rheostat-type control C. can only be synchronous speed at full load D. can only attain synchronous speed at no load

Description : The speed of a wound-rotor induction motor _____________. A. will be fixed by the number of field poles B. can be varied by a rheostat-type control C. can only be synchronous speed at full load D. can only attain synchronous speed at no load

Last Answer : Answer: B

The synchronous speed of an induction motor is the ________. A. speed at which the rotor turns B. speed of the rotating field C. frequency of the rotor current D. slip in per cent of rotor RPM

Description : The synchronous speed of an induction motor is the ________. A. speed at which the rotor turns B. speed of the rotating field C. frequency of the rotor current D. slip in per cent of rotor RPM

Last Answer : Answer: B

An increase in which of the listed conditions will increase the speed of a synchronous motor? A. Frequency B. Voltage C. Armature current D. Inductance

Description : An increase in which of the listed conditions will increase the speed of a synchronous motor? A. Frequency B. Voltage C. Armature current D. Inductance

Last Answer : Answer: A

The rotor of a synchronous motor operates in synchronism with the rotating field because ______________. A. of the amortisseur windings B. the rotor is magnetically locked into step with the rotating magnetic field by the excitation current C. the field strength varies directly with rotor slip D. the stator flux rotates in the opposite direction

Description : The rotor of a synchronous motor operates in synchronism with the rotating field because ______________. A. of the amortisseur windings B. the rotor is magnetically locked into step with the ... field strength varies directly with rotor slip D. the stator flux rotates in the opposite direction

Last Answer : Answer: B

Which of the listed instruments can be best used to locate a grounded field coil in a synchronous motor? A. Frequency meter B. Megohmmeter C. Voltmeter D. Multimeter

Description : Which of the listed instruments can be best used to locate a grounded field coil in a synchronous motor? A. Frequency meter B. Megohmmeter C. Voltmeter D. Multimeter

Last Answer : Answer: B

A shaded-pole motor is a ____________. A. synchronous motor B. three-phase induction motor C. compound-wound motor D. single-phase induction motor

Description : A shaded-pole motor is a ____________. A. synchronous motor B. three-phase induction motor C. compound-wound motor D. single-phase induction motor

Last Answer : Answer: D

The purpose of squirrel-cage windings in a synchronous motor is to ______________. A. provide more precise balancing B. produce a higher power factor C. eliminate arcing between the stator and the frame D. provide a means for starting

Description : The purpose of squirrel-cage windings in a synchronous motor is to ______________. A. provide more precise balancing B. produce a higher power factor C. eliminate arcing between the stator and the frame D. provide a means for starting

Last Answer : Answer: D

The purpose of amortisseur windings in a synchronous motor is to ______________. A. reduce eddy current losses B. produce a higher power factor C. provide a means for starting D. eliminate arcing between the stator and the rotor

Description : The purpose of amortisseur windings in a synchronous motor is to ______________. A. reduce eddy current losses B. produce a higher power factor C. provide a means for starting D. eliminate arcing between the stator and the rotor

Last Answer : Answer: C

A damper winding is designed as part of a synchronous motor to ____________. A. increase efficiency B. provide starting torque C. provide excitation D. eliminate slippage

Description : A damper winding is designed as part of a synchronous motor to ____________. A. increase efficiency B. provide starting torque C. provide excitation D. eliminate slippage

Last Answer : Answer: B

The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply

Description : The most common source of excitation for synchronous motors is a/an _____________. A. low voltage battery B. motor attenuator set C. DC exciter generator D. AC supply

Last Answer : Answer: C

On an engine throttle control system, the auxiliary control circuits are provided with devices to prevent excessive overtravel of the pilot valve by the synchronous motor. These devices are called _________________. A. overlap sensors B. limit switches C. overtravel relays D. proximity switches

Description : On an engine throttle control system, the auxiliary control circuits are provided with devices to prevent excessive overtravel of the pilot valve by the synchronous motor. These devices are called _________________. A. overlap sensors B. limit switches C. overtravel relays D. proximity switches

Last Answer : Answer: B

The function of amortisseur, or damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency

Description : The function of amortisseur, or damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency

Last Answer : Answer: C

A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor magnets to lock in with the rotating flux of the stator C. the stator poles are dragged around due to the flux created by the excitation current D. the stator flux rotates in the opposite direction

Description : A synchronous motor maintains synchronism with the rotating field because _____________. A. field strength varies directly with rotor slip B. DC current applied to the rotor coils causes the rotor ... the flux created by the excitation current D. the stator flux rotates in the opposite direction

Last Answer : Answer: B

The function of damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency

Description : The function of damper windings in a synchronous motor is to _____________. A. eliminate slippage B. provide excitation C. provide starting torque D. increase efficiency

Last Answer : Answer: C