How do split-phase induction motors become self-starting?

How do split-phase induction motors become self-starting?
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1 Answer

Answer :

By using combinations of inductance and capacitance to apply  out-of phase currents in starting windings.
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Related questions

Which statement is true concerning a split-phase induction motor? A. Motor rotation can be reversed without changing the windings or leads. B. Motor speed can be readily adjusted from zero to full speed. C. The motor will run as a generator with the proper wiring. D. Motor rotation can be reversed by reversing the leads on the starting winding.

Description : Which statement is true concerning a split-phase induction motor? A. Motor rotation can be reversed without changing the windings or leads. B. Motor speed can be readily adjusted from zero to full ... proper wiring. D. Motor rotation can be reversed by reversing the leads on the starting winding.

Last Answer : Answer: D

If the centrifugal switch or relay used for cutting out the starting winding of a split-phase induction motor fails to open once the motor is in operation, the _____________. A. motor will overspeed B. starting winding will burn out C. motor will immediately stall under load D. motor torque will be above normal at rated speed

Description : If the centrifugal switch or relay used for cutting out the starting winding of a split-phase induction motor fails to open once the motor is in operation, the _____________. A. motor will overspeed B ... C. motor will immediately stall under load D. motor torque will be above normal at rated speed

Last Answer : Answer: B

Which of the following problems will most likely occur if the starting winding of a split-phase induction motor failed to cutout once the motor was in continuous operation? A. The motor will overspeed. B. The motor will run at a reduced speed. C. A time delay will stop the motor. D. The winding will burn out.

Description : Which of the following problems will most likely occur if the starting winding of a split-phase induction motor failed to cutout once the motor was in continuous operation? A. The motor will overspeed. B. The ... reduced speed. C. A time delay will stop the motor. D. The winding will burn out.

Last Answer : Answer: D

Why is the starting torque of a resistance split-phase induction motor not high?

Description : Why is the starting torque of a resistance split-phase induction motor not high?

Last Answer : The starting torque is given as, Ts = K Im Is Sin Ф Where K = constant whose magnitude depends upon the design of the motor (i) The angle between Is and Im is small ... Im are not equal in magnitude, the rotating magnetic field is not uniform and the starting torque produced is small.

Why single-phase motors are not self-starting?

Description : Why single-phase motors are not self-starting?

Last Answer : When a 1φ supply is given to the single winding of the single phase motor, the field produced by it changes in magnitude and direction sinusoidally (pulsating flux). Such and alternating field is equivalent ... developed by the motor is equal to zero. So a single-phase motor is not self-starting.

What are methods available for making single phase induction motor a self starting?

Description : What are methods available for making single phase induction motor a self starting?

Last Answer : By slitting the single phase, by providing shading coil in the poles.

Why single phase induction motor is not a self starting one?

Description : Why single phase induction motor is not a self starting one?

Last Answer : When motor fed supply from single phase, its stator winding produces an alternating flux, which doesn’t develop any torque.

How is a three phase cage induction motor self starting?

Description : How is a three phase cage induction motor self starting?

Last Answer : Any type of induction motor is self starting. Because the reason for torqe production require two flux displaced by some angle theta.If theta is constant with time then torqe will be constant;if ... torqe also pulsating. In induction motor this angle theta is not pulsating.so it is self starting 

Autotransformer starters or compensators are sometimes used with polyphase induction motors to _____________. A. reduce the voltage applied to the motor during the starting period B. increase the voltage for 'across-the-line starting' C. provide a backup means of voltage regulation for emergency starting D. allow the voltage to be either stepped up or down, depending on the application, to ensure full torque

Description : Autotransformer starters or compensators are sometimes used with polyphase induction motors to _____________. A. reduce the voltage applied to the motor during the starting period B. increase the voltage for ' ... to be either stepped up or down, depending on the application, to ensure full torque

Last Answer : Answer: A

Why do we use capacitor-start induction motors in applications requiring high starting torque in preference to repulsion induction motors?

Description : Why do we use capacitor-start induction motors in applications requiring high starting torque in preference to repulsion induction motors?

Last Answer : Capacitors are easily available, cheaper and reliable. Repulsion-induction motors posses a special commutator and brushes that require maintenance. Most manufacturers have stopped making them.

Why do we use capacitor-start induction motors in applications requiring high starting torque in preference to repulsion induction motors?

Description : Why do we use capacitor-start induction motors in applications requiring high starting torque in preference to repulsion induction motors?

Last Answer : Ans : Capacitors are easily available, cheaper and reliable. Repulsion-induction motors posses a special commutator and brushes that require maintenance. Most manufacturers have stopped making them.

What type of rotor is used in split-phase motors? A. Drum B. Salient pole C. Squirrel-cage D. Wound-rotor

Description : What type of rotor is used in split-phase motors? A. Drum B. Salient pole C. Squirrel-cage D. Wound-rotor

Last Answer : Answer: C

Why are resistance split-phase inductions motors most popular?

Description : Why are resistance split-phase inductions motors most popular?

Last Answer : These motors are most popular due to their low cost. They are used where moderate starting torque is required and where the starting periods are not frequent. They drive fans, pumps, washing machines, small machine tools etc. They have power rating between 60 watts and 250 watts.

Synchronous motors are generally not self-starting because?

Last Answer : Synchronous motors are generally not self-starting because the direction of instantaneous torque reverses after half cycle.

Most three-phase induction motors of five horsepower or less, are started by _____________. A. autotransformer starters B. resistor starters C. across-the-line starters D. reactor starters

Description : Most three-phase induction motors of five horsepower or less, are started by _____________. A. autotransformer starters B. resistor starters C. across-the-line starters D. reactor starters

Last Answer : Answer: C

Most three-phase induction motors used for driving engine room auxiliaries are started by _____________. A. resistor starters B. across-the-line starters C. impedance starters D. reactor starters

Description : Most three-phase induction motors used for driving engine room auxiliaries are started by _____________. A. resistor starters B. across-the-line starters C. impedance starters D. reactor starters

Last Answer : Answer: B

Why are centrifugal switches provided on many 1-phase Induction motors?

Description : Why are centrifugal switches provided on many 1-phase Induction motors?

Last Answer : Centrifugal switches are provided on many 1-phase Induction motors to disconnect the starting / auxiliary winding from the supply when the motor reaches about 70% of its synchronous speed.

Name types of 1-phase induction motors.

Description : Name types of 1-phase induction motors.

Last Answer : Based on the method of starting arrangement provided, the 1-phase Induction motors are classified as follows (i) Split-phase motor (ii) Shaded pole motor (iii) Resistor start Induction run ... iv) capacitor start Induction run single phase IM (v) capacitor start Capacitor run single phase IM

Name the two different theories with which principle of 1-phase induction motors are explained

Description : Name the two different theories with which principle of 1-phase induction motors are explained

Last Answer : The two different theories are · Double revolving field theory · Cross field theory

Where do we require single-phase induction motors?

Description : Where do we require single-phase induction motors?

Last Answer : Single-phase induction motors are required where (i) 3 phase supply is not available (ii) Efficiency is of lesser importance (iii) Rating is less than one H.P. (iv) Equipment is portable

SINGLE PHASE INDUCTION MOTORS MCQ

Description : SINGLE PHASE INDUCTION MOTORS MCQ

Last Answer : 101. After the starting winding of a single phase induction motor is disconnected from supply, it continues to run only on (a) running winding (b) rotor winding (c) field winding (d) compensating winding Ans: a ... motor is usually reduced by using (a) gearing (b) belts (c) brakes (d) chains Ans: a

THREE PHASE INDUCTION MOTORS MCQ

Description : THREE PHASE INDUCTION MOTORS MCQ

Last Answer : 101. Insertion of resistance in the stator of an induction motor (a) increases the load torque (b) decreases the starting torque (c) increases the starting torque (d) none of the above Ans: b

State the types of single phase induction motors.

Description : State the types of single phase induction motors.

Last Answer : The types of single phase induction motors are: i) Resistance split phase induction motor. ii) Capacitor split phase inductor motor. a. Capacitor start induction run motor b. permanent capacitor motor c. capacitor start capacitor run induction motor iii) Shaded pole induction motor.

State the classification of single phase induction motors.

Description : State the classification of single phase induction motors.

Last Answer : Types of single phase induction motors: 1. Split phase induction motor. 2. Capacitor start inductor motor. 3. Capacitor start capacitor run induction motor. 4. Permanent split capacitor motor. 5. Shaded pole induction motor. 

Deep bar rotor construction is used in three phase induction motors to mainly:

Description : Deep bar rotor construction is used in three phase induction motors to mainly: (1) Control speed (2) Control power factor (3) Increase starting torque (4) None of these

Last Answer : Deep bar rotor construction is used in three phase induction motors to mainly: Increase starting torque

A split-phase induction squirrel-cage motor will not come up to speed, even though the rated voltage, rated frequency, and rated load are applied. The suspected trouble could be due to _____________. A. a faulty centrifugal switch B. broken rotor bars C. worn bearings D. all of the above

Description : A split-phase induction squirrel-cage motor will not come up to speed, even though the rated voltage, rated frequency, and rated load are applied. The suspected trouble could be due to _____________. A. a faulty centrifugal switch B. broken rotor bars C. worn bearings D. all of the above

Last Answer : Answer: D

The variable resistance placed in the rotor circuit of a wound-rotor induction motor provides for __________. A. speed control B. frequency control C. voltage control D. use as a split-phase motor

Description : The variable resistance placed in the rotor circuit of a wound-rotor induction motor provides for __________. A. speed control B. frequency control C. voltage control D. use as a split-phase motor

Last Answer : Answer: A

How the speed of rotation of a split phase induction motor is reversed?

Description : How the speed of rotation of a split phase induction motor is reversed?

Last Answer : The terminal connections of the starting windings are reversed with respect to main running windings..

What is the draw back of the resistance split-phase induction motor?

Description : What is the draw back of the resistance split-phase induction motor?

Last Answer : The starting winding has a relatively small number of turns of fine wire and its resistance is higher than that of the main winding. Therefore the current density is high and the winding heats up quickly. ... begins to smoke and may burn out unless the motor is protected by a built-in-thermal relay.

Explain the working of resistance split phase induction motor with a neat diagram.

Description : Explain the working of resistance split phase induction motor with a neat diagram.

Last Answer : Circuit diagram of resistance split single phase induction motor:   * Working of resistors split single phase induction motor: To make a single phase induction motor self-starting, we ... function is to automatically disconnected the starting winding from the supply Once motor is started. 

Split phase induction motor

Description : Split phase induction motor

Last Answer : Split phase induction motor : There are two windings used in split phase induction motor. It is a type of single-phase induction motor. There are two winding one is called main winding and ... motor have low starting torque it is used for small fans, blowers, centrifugal pumps, grinders etc.

In a split-phase induction motor, the resistance/reactance ratios of windings are such that

Description : In a split-phase induction motor, the resistance/reactance ratios of windings are such that (A) current in the auxiliary winding leads the current in the main winding (B) current in the ... (C) both windings develop the same starting torque (D) both windings develop high starting current

Last Answer : In a split-phase induction motor, the resistance/reactance ratios of windings are such that current in the auxiliary winding leads the current in the main winding

What is the main function in the use of a capacitor for starting a single phase motor? A. Reduce radio interference B. Split the phase to establish a rotating magnetic field C. Reduce the phase angle D. Prolong the life of the starting contacts

Description : What is the main function in the use of a capacitor for starting a single phase motor? A. Reduce radio interference B. Split the phase to establish a rotating magnetic field C. Reduce the phase angle D. Prolong the life of the starting contacts

Last Answer : Answer: B

The main purpose of the auxiliary winding on a split-phase, single-phase motor is to _____________. A. limit the starting voltage B. increase the starting current C. start the motor D. keep the motor running in the event the main winding should fail

Description : The main purpose of the auxiliary winding on a split-phase, single-phase motor is to _____________. A. limit the starting voltage B. increase the starting current C. start the motor D. keep the motor running in the event the main winding should fail

Last Answer : Answer: C

Is induction motor is self starting?

Description : Is induction motor is self starting?

Last Answer : Single phase induction motor is not self starting. Three phase induction motor is self starting.

A single-phase induction motor starts, comes up to about 75% rated speed, slows down to a lower speed, and accelerates again. The problem is most likely in the ____________. A. starting winding B. running winding C. starting capacitor D. running centrifugal switch

Description : A single-phase induction motor starts, comes up to about 75% rated speed, slows down to a lower speed, and accelerates again. The problem is most likely in the ____________. A. starting winding B. running winding C. starting capacitor D. running centrifugal switch

Last Answer : Answer: B

A single-phase induction motor will only start if you spin the rotor rapidly with the line switch closed. After starting, its speed fluctuates between very slow and half-speed. The problem probably lies in the ________. A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Description : A single-phase induction motor will only start if you spin the rotor rapidly with the line switch closed. After starting, its speed fluctuates between very slow and half-speed. The problem ... in the ________. A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Last Answer : Answer: D

A single-phase induction motor fails to start. The rotor is spun rapidly with the line switch closed. Having started by this method it is noted that the motor fluctuates between a very slow speed and half speed. The problem probably lies in the ______ A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Description : A single-phase induction motor fails to start. The rotor is spun rapidly with the line switch closed. Having started by this method it is noted that the motor fluctuates between a very slow ... lies in the ______ A. starting winding B. centrifugal mechanism C. centrifugal switch D. running winding

Last Answer : Answer: D

A single-phase induction motor having a relatively high starting torque, is the ___________. A. shaded pole motor B. wound-rotor motor C. capacitor-start motor D. resistance-start motor

Description : A single-phase induction motor having a relatively high starting torque, is the ___________. A. shaded pole motor B. wound-rotor motor C. capacitor-start motor D. resistance-start motor

Last Answer : Answer: C

Why shaded-pole single phase induction motor does not need any special starting technique like capacitors and auxiliary winding etc.

Description : Why shaded-pole single phase induction motor does not need any special starting technique like capacitors and auxiliary winding etc.

Last Answer : Because it is inherently self started motor. The construction of the poles is such that they give a sweep to the magnetic flux and motor starts rotating.

How the starting winding produce rotation in a single phase resistance start induction motor?

Description : How the starting winding produce rotation in a single phase resistance start induction motor?

Last Answer : The starting winding is highly resistive and the main winding is inductive. So the phase difference between the two currents becomes nearly 90 degree and hence the motor start as two phase motor.

What is the function of centrifugal starting switch in a single-phase induction motor?

Description : What is the function of centrifugal starting switch in a single-phase induction motor?

Last Answer : Ans: The centrifugal switch is connected in series with the starting winding. The primary function of the centrifugal switch is to produce rotating flux in conjunction with main winding at the time of ... has no function to perform and is removed from the circuit by a centrifugally operated switch.

why the three phase induction motor draws heavy current at starting?

Description : why the three phase induction motor draws heavy current at starting?

Last Answer : At the time of starting, the rotor speed is zero hence slip is 1, the emf induced in rotor winding is very high. Hence rotor current is also very high. The starting current is 5 to 7 times more than its full load current.

A 3-phase delta connected squirrel cage induction motor when started with a DOL starter has a starting

Description : A 3-phase delta connected squirrel cage induction motor when started with a DOL starter has a starting torque of 600 NM. Its starting torque when star delta starter is used:

Last Answer : A 3-phase delta connected squirrel cage induction motor when started with a DOL starter has a starting torque of 600 NM. Its starting torque when star delta starter is used: 200 NM

A three-phase squirrel cage induction motor has a starting torque of 150% and a maximum torque of 300%

Description : A three-phase squirrel cage induction motor has a starting torque of 150% and a maximum torque of 300% with respect to rated torque at rated voltage and rated frequency. Neglect the stator resistance and rotational losses. The ... maximum torque is  (A) 13.48% (B) 16.42% (C) 18.92% (D) 26.79%

Last Answer : A three-phase squirrel cage induction motor has a starting torque of 150% and a maximum torque of 300% with respect to rated torque at rated voltage and rated frequency. Neglect the stator resistance and rotational losses. The value of slip for maximum torque is 26.79%

Starting torque can be obtained in the case of a single phase induction motor with identical main and ...

Description : Starting torque can be obtained in the case of a single phase induction motor with identical main and auxiliary windings by connecting:  (1) A capacitor across the mains (2) A capacitor in ... with the auxiliary winding (4) Equal value capacitors in series with the main and the auxiliary windings

Last Answer : Starting torque can be obtained in the case of a single phase induction motor with identical main and auxiliary windings by connecting:  A capacitor is series with the auxiliary winding.

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.

which single phase induction motor has highest starting torque?

Last Answer : Capacitor start motor has high torque in starting

During the final stage of cell division, the mitotic apparatus disappears, the chromosomes become attenuated, the centrioles duplicate and split, the nuclear membrane becomes reconstituted and the nucleolus reappears. This phase of cell division is known as:

Description : During the final stage of cell division, the mitotic apparatus disappears, the chromosomes become attenuated, the centrioles duplicate and split, the nuclear membrane becomes reconstituted and the nucleolus reappears. This ... as: a) prophase (pron: prO-phase) b) metaphase c) anaphase d) telophase

Last Answer : ANSWER: D -- Telophase