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.
Description : what is the application of shaded pole induction motor?
Last Answer : Because of its small starting torque, it is generally used for small fans, toys, instruments, hair driers, tape recorder, advertising display, ventilators, electric clock etc.
Description : What is the principle of operation of shaded-pole induction motor?
Last Answer : A shaded-pole motor is basically a small single-phase squirrel cage motor in which the starting winding is composed of short-circuited copper ring (called shading coil) surrounding one-third of each pole ... rotating magnetic field. As a result, the rotor is set in motion due to induction principle.
Description : Name the two winding of single phase induction motor?
Last Answer : Running and starting winding.
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.
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.
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.
Description : What is size of shaded-pole motor?
Last Answer : These are usually built in small fractional H.P, not exceed 1/4 H.P.
Description : In which direction does a shaded pole motor run?
Last Answer : The rotor starts rotation in the direction from unshaded part to the shaded part.
Description : what do you mean by shaded pole motor?
Last Answer : These motor have projected pole with 1/3 pole part rapped with a copper strip. This portion of the pole is called shaped part of the pole because of this a revolving field is set up in the Stator and torque is developed.
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.
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
Description : What is the function of capacitor in single phase induction motor?
Last Answer : To make phase difference between starting and running winding, to improve PF and to get more torque
Description : why single-phase induction motor has low power factor?
Last Answer : The current through the running winding lags behind the supply voltage by a very large angle. Therefore power factor is very low.
Description : what do you mean by single phase induction motor?
Last Answer : A machine that converts 1 phase ac electrical power into mechanical power by using a electromagnetic induction phenomenon is called a 1 phase induction motor.
Description : Why is the starting torque of a capacitor start induction motor high?
Last Answer : Ans: The capacitor C in the starting winding is so chosen that Is leads Im by 75 degree. Since the starting torque is directly proportional to Sin Ф, and it is quite high in capacitor-start induction motor.
Description : Is there any relation between the capacitances of two capacitors used in two value capacitor start capacitor run motor?
Last Answer : Ans: Starting capacitor has about 10 – 15 times high capacity than the value of running capacitor.
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..
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.
Description : What are the inherent characteristics of plain 1-phase Induction motor ?
Last Answer : 1-phase Induction motor is not used in practice due to the following inherent characteristics · 1-phase Induction motor does not have any starting torque · However, if the rotor is initially ... up its speed in a direction at which the initial torque is given and deliver the required output
Description : In a capacitor start single-phase induction motor, the capacitor is connected (A) in series with main winding. (B) in series with auxiliary winding. (C) in series with both the windings. (D) in parallel with auxiliary winding.
Last Answer : Ans: B To make single phase motor self start. We split the phases at 90 degree. Hence, motor behaves like a two phase motor.
Description : How the starting winding is made resistive?
Last Answer : It consists of only few turns of smaller diameter.
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
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
Description : In the illustrated device, the part labeled '1A' _________. EL-0001 A. are start and run windings for a single phase shaded pole induction motor B. is the stator for a polyphase induction ... armature for a squirrel cage rotor motor D. are direct current shunt field windings for a universal motor
Last Answer : Answer: B
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
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.
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.
Description : If a single phase motor is driven in any direction by any means, it starts running in that direction. Explain why?
Last Answer : Actually a pulsating torque has two components which are equal in magnitude and rotate in opposite direction with synchronous speed at unity slip. Now if the motor rotates in any direction, the ... component in this direction increases than the other component and hence motor runs in that direction.
Description : What is the use of shading ring in a pole motor?
Last Answer : The shading coil causes the flux in the shaded portion to lag behind the flux in unshaded portion of pole. This gives in effect a rotation of flux across the pole face and under the influence of this moving flux a staRting torque is developed.
Description : Differentiate between “capacitor start “and “capacitor start capacitor run“ induction motor?
Last Answer : In capacitor start motor, capacitor is connected in series with the starting winding. But it will be disconnected fro m the supply, when the motor picks up its speed. But ... capacitor are not disconnected, but always connected in the supply .so it has high starting and running torque.
Description : what is the type of induction motor used in wet grinders?
Last Answer : Capacitor start capacitor run single-phase induction motor.
Description : Give application of capacitor start capacitor run Induction motor
Last Answer : Ceiling fan, air conditioner, blowers, table fans, conveyors etc
Description : How is the direction of a capacitor start Induction motor be reversed?
Last Answer : The direction of rotation can be reversed by interchanging the terminals of either the main winding or the starting winding.
Description : Give applications of resistance start Induction run motor?
Last Answer : Fans, Lathe machines, blowers, refrigerator , separators, washing machine etc
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.
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
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
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
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
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
Description : After servicing a single phase fan it was found to run in reverse direction. What could be the reason?
Last Answer : The connection to the starting/ auxiliary winding would have reversed.
Description : How speed control is made in single phase motors?
Last Answer : It is usually controlled by applying a variable voltage from tapped transformers, variacs, potentio meters, and tapped reactors.
Description : Which type of torque is developed in single phase motors?
Last Answer : Pulsating torque is produced.
Description : Which type of rotor is used in single phase motors?
Last Answer : Squirrel cage type
Description : Which type of AC single-phase motor will also operate on direct current? A. Split-phase B. Series-wound C. Shaded-pole D. Repulsion-start
Description : Why capacitor –start induction motors advantageous?
Last Answer : In capacitor start induction motors capacitor is connected in series with the auxiliary winding. When speed of the motor approaches to 75 to 80% of the synchronous speed the starting winding gets ... torque is proportional to phase angle ά and hence such motors produce very high starting torque.
Description : Give applications of Capacitor start Induction run motors.
Last Answer : Drilling machine, centrifugal pump, grinders , refrigerator etc
Description : What happens when the centrifugal starting switch fails to open?
Last Answer : Ans: If the starting switch fails to open when needed, then the starting winding will overheat and burn out and motor will not start next time.
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.