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 : Why a single phase motor is not a self starting motor
Last Answer : The motor mechanical degree 360 degree this must covered revolving field so single phase to starting need starting winding with 90 degree to main winding
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.
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
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
Last Answer : Answer: D
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 : 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 : 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 : 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.
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 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 : 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.
Description : What are the methods of starting synchronous motor?
Last Answer : 1. Pony motor starting( using ac or dc motor) 2. Starting as squirrel cage Induction motor or using damper winding 3. Starting as slip ring Induction motor or synchronous motor 4. Using dc machine coupled to it.
Description : Mention the methods for starting an induction motor?
Last Answer : The different methods of starting an induction motor DOL:direct online starter Star delta starter Auto transformer starter Resistance starter Series reactor starter
Description : What are the different methods for the starting of a synchronous motor.
Last Answer : Starting methods: Synchronous motor can be started by the following two methods: By means of an auxiliary motor: The rotor of a synchronous motor is rotated by auxiliary motor. Then ... rotor and the rotor starts rotating continuously as the rotor field is locked with stator revolving field.
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
Description : Why synchronous motor is not self starting?
Last Answer : Synchronous motor is a doubly excited machine i.e two electrical inputs are provided to it. It's stator winding which consists of a 3 phase winding is provided with 3 phase supply and rotor ... due to attractive or repulsive force and remain in standstill condition. Hence it is not self starting.
Description : A hysteresis motor (A) is not a self-starting motor. (B) is a constant speed motor. (C) needs dc excitation. (D) can not be run in reverse speed.
Last Answer : (B) is a constant speed motor
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.
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
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.
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 : 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.
Description : List out the methods of speed control of cage type 3-phase induction motor?
Last Answer : a) By changing supply frequency b) By changing the number of poles c) By operating two motors in cascade
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.
Last Answer : The starting winding of a single-phase motor is placed in stator.
Last Answer : Reason is kinetic energy
Last Answer : If starting winding of a single-phase induction motor is left in the circuit, it will draw excessive current and overheat.
Last Answer : Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a magnetic relay.
Last Answer : The rotor developed by a single-phase motor at starting is zero.
Last Answer : Capacitor start motor has high torque in starting
Description : If a single-phase induction motor fails to start, the problem may be _____________. A. an open in the main winding B. a shorted shunt field C. a closed centrifugal switch D. low circuit frequency
Last Answer : Answer: A
Description : If a single-phase induction motor fails to start, the problem may be _____________. A. an open in the run winding B. a shorted shunt field C. a closed centrifugal switch D. low circuit frequency
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
Description : In the illustration, the assembly labeled 2 is a ________. EL-0001 A. wound rotor and shaft for a single phase induction motor B. conduction rotor and shaft for a polyphase induction motor C. ... cage rotor and shaft for a polyphase motor D. squirrel cage rotor for a single phase induction motor
Description : If the illustrated motor fails to start and gives a loud hum when the start button is pushed, the problem is ________. EL-0007 A. one of the phases to the motor is not energized because of ... electrical distribution system D. 'OL1' is open because of 'T1' overload causing the motor to single phase
Description : If a three-phase induction motor malfunctions and drops to a single-phase (one supply line open) ____________. A. the motor will continue to run if it is not heavily loaded B. more torque will be ... be able to be restarted D. the motor will immediately stop and can only be restarted at no load
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 : A shaded-pole motor is a ____________. A. synchronous motor B. three-phase induction motor C. compound-wound motor D. single-phase induction motor
Description : The diagram shown in the illustration represents a _________. EL-0058 A. dual speed, 2-winding motor controller B. navigation running light circuit C. single phase, 2-motor selectable starter D. common fluorescent lighting circuit
Description : What Are The Advantages Of Three Phase Motor Over Single Phase Motor?
Last Answer : Three phase motors are having Higher starting torques Improved speed regulation Less vibration Quieter operation compared to the single phase motors.
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 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 : Name the two winding of single phase induction motor?
Last Answer : Running and starting winding.
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 : A single phase Hysteresis motor (A) can run at synchronous speed only (B) can run at sub synchronous speed only (C) can run at synchronous and super synchronous speed (D) can run at synchronous and sub synchronous speed
Last Answer : Ans: A The rotor revolves synchronously because the rotor poles magnetically lock up with the revolving stator poles of opposite polarity
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.