Why starter is required for starting an induction motor?
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asked
Mar 15, 2018
by
anonymous

In a double squirrel cage induction motor, good starting torque is produced as (A) Large current flows through the outer high resistance winding. (B) Large current flows through the inner high ... the outer high resistance winding. (D) Large current flows through the inner low resistance winding.
Last Answer : In a double squirrel cage induction motor, good starting torque is produced as Large current flows through the outer high resistance winding.
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1 answer
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May 8, 2018
by
anonymous
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Last Answer : If starting winding of a single-phase induction motor is left in the circuit, it will draw excessive current and overheat.
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236 views
1 answer
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Mar 20, 2018
by
anonymous

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
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1 answer
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Mar 17, 2018
by
anonymous

Is induction motor is self starting?
Last Answer : Single phase induction motor is not self starting. Three phase induction motor is self starting.
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112 views
1 answer
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Mar 17, 2018
by
anonymous

Last Answer : Capacitor start motor has high torque in starting
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136 views
1 answer
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Sep 13, 2017
by
anonymous

Why a dc series motor has a high starting torque?
Last Answer : motor
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86 views
1 answer
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Mar 15, 2018
by
anonymous

Last Answer : An induction motor has relatively high power factor at near full load.
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1 answer
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Mar 20, 2018
by
anonymous

Why high starting torque is required?
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0 answers
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Mar 15, 2018
by
anonymous

Last Answer : Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of D.C. series motor.
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Mar 20, 2018
by
anonymous

Last Answer : Reason is kinetic energy
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290 views
2 answers
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Mar 20, 2018
by
anonymous

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.
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1 answer
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May 7, 2020
by
anonymous

Last Answer : For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.
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1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The starting resistance of a D.C. motor is generally low.
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1 answer
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Mar 20, 2018
by
anonymous
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Last Answer : For starting a D.C. motor a starter is required because it limits the starting current to a safe value.
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Mar 20, 2018
by
anonymous

Last Answer : The starting winding of a single-phase motor is placed in stator.
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Mar 20, 2018
by
anonymous

Last Answer : Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a magnetic relay.
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Mar 20, 2018
by
anonymous

Last Answer : The value of starting capacitor of a fractional horse power motor will be 300 uF .
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Mar 20, 2018
by
anonymous

Last Answer : A centrifugal switch is used to disconnect starting winding when motor has picked up about 50 to 70 per cent of rated speed.
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Mar 20, 2018
by
anonymous

Last Answer : The rotor developed by a single-phase motor at starting is zero.
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Mar 20, 2018
by
anonymous
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Last Answer : In a capacitor start motor, the phase displacement between starting and running winding can be nearly 90°.
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1 answer
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Mar 20, 2018
by
anonymous

A synchronous motor can be made self starting by providing?
Last Answer : A synchronous motor can be made self-starting by providing damper bar.
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1 answer
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Mar 18, 2018
by
anonymous

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
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Aug 18, 2019
by
anonymous

Define Slip of Induction Motor.
Last Answer : Slip: It is the ratio of relative speed of rotor (difference between synchronous speed and rotor speed) to the synchronous speed of rotating magnetic field. Slip = (NS – N) / NS where , NS = synchronous speed, N = speed of rotor
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Aug 17, 2019
by
anonymous

Explain the working of a single phase capacitor start induction motor.
Last Answer : Single phase capacitor start induction motor https://youtu.be/31lvvzU5Puc
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414 views
2 answers
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Jul 30, 2019
by
anonymous

State any four advantages of three phase induction motor.
Last Answer : Advantages of three phase induction motor https://youtu.be/27OIOCKN05U
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140 views
2 answers
asked
Jul 30, 2019
by
anonymous

In a single-phase induction motor, the operating direction is determined by the ________ A) Rotor B) Stator C) Starting circuit D) None of these
Last Answer : In a single-phase induction motor, the operating direction is determined by the Starting circuit
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1 answer
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Apr 29, 2018
by
anonymous

What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these
Last Answer : What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these
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127 views
1 answer
asked
Apr 29, 2018
by
anonymous

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
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2 answers
asked
Dec 31, 2017
by
anonymous

how can we reverse the direction of rotation of three phase induction motor ?
Last Answer : The direction of rotation of three phase induction motor can be reversed by plugging i.e by changing any two out of three phases of the supply to the stator of the Induction motor terminal.
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1 answer
asked
Oct 4, 2017
by
anonymous

In the induction type directional over current relay, when a short-circuit occurs in the circuit (A) power flows in reverse direction (B) power flows in normal direction (C) directional power element does not operate (D) over current element is not energized
Last Answer : In the induction type directional over current relay, when a short-circuit occurs in the circuit power flows in reverse direction
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1 answer
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Apr 28, 2018
by
anonymous

Last Answer : An induction meter can handle current up to 100 A.
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Mar 21, 2018
by
anonymous

Basic electrical engineering
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0 answers

Explain the working principle of induction motor.
Last Answer : Working principle of induction motor: * When the motor is excited with three-phase supply, three-phase stator winding carries three-phase currents & produces a rotating magnetic field of constant magnitude and ... , which tend to move the rotor in the same direction as the rotating magnetic field.
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1 answer
asked
May 22, 2020
by
anonymous

Explain the activities carried out during weekly maintenance of 3 ph. Induction motor.
Last Answer : Activities Carried out During Weekly Maintenance of 3 ph. Induction Motor: 1) Check belt tension. In cases where this is excessive it should immediately be reduces and in the case of sleeve ... and cooled by oil mist systems its important to check the oil mist flow paths/pressure components.
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163 views
1 answer
asked
May 7, 2020
by
anonymous

State the function of following parts in Induction motor. (i) Stator (ii) Slip rings
Last Answer : Name of part Function Stator 1) Stator frame supports the core, terminal box and protects the inner parts. 2) Stator core houses stator winding. 3) Stator winding ... ) Provides facility to connect external resistance to rotor circuit through brushes for starting and control.
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223 views
1 answer
asked
May 7, 2020
by
anonymous

List the energy conservation technique in induction motor.
Last Answer : Following are the list of energy conservation techniques in electrical motors: 1) Reduction in iron losses by using low loss silicon steel core material laminated to thinner dimension. 2) Using bigger length ... at light load. 13) By rewinding in induction motor 14) By motor survey
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1.2k views
1 answer
asked
May 3, 2020
by
anonymous

With a neat sketch give the working of shaded pole induction motor.
Last Answer : Explanation: It has squirrel cage rotor and salient pole stator. The stator poles are shaded partially by short circuited conductor band to create the phase difference between the fluxes emerging from shaded ... rotating magnetic field in the air-gap and torque is exerted on the squirrel cage rotor.
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2 answers
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Apr 27, 2020
by
anonymous

Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.
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Apr 16, 2020
by
anonymous

Explain the need and steps to conduct the reduced voltage running up test on the three phase induction motor.
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Apr 16, 2020
by
anonymous

Last Answer : Energy conservation technique in induction motor by minimizing idle and redundant running of motor: 1) Loss of energy as the no load power drawn is approximately about 12% to 16% of rated ... to unnecessary line losses. 4) Reduction in overall system energy efficiency over period of time.
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694 views
1 answer
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Sep 22, 2018
by
anonymous

State and explain any four factors governing selection of induction motor.
Last Answer : The factors governing the selection of Induction motor: 1) Load torque required at normal speed matches with available torque of motor. 2) Break down torque or pull out torque or maximum torque ... If selecting energy efficient motor the cost benefit analysis over the long run must be worked out.
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2.8k views
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Sep 22, 2018
by
anonymous

Explain energy conservation technique “by improving power quality” for induction motor.
Last Answer : Energy conservation method in induction motor by improving power quality: Electrical energy can be conserved by improving the power quality. It can be achieved by avoiding voltage unbalance, maintaining ... losses can be minimized by using harmonic filter thus reducing the harmonics in the system.
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3.6k views
2 answers
asked
Sep 22, 2018
by
anonymous

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.
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233 views
1 answer
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Sep 20, 2018
by
anonymous

State starters used for i) 3-Ph squirrel cage induction motor (3HP) ii) D.C. motor
Last Answer : Name the starters used for following motors : i) 3 H.P. 3-Ph squirrel cage I.M: i) DOL starter OR ii) Star-Delta Starter OR ii) Auto transformer starter OR iii) Soft start starter. ii) D.C Shunt Motor : 1) Armature resistance starter (Three Point Starter) OR 2) Four Point Starter
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155 views
1 answer
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Sep 18, 2018
by
anonymous

A change of 4% in the supply voltage to an induction motor will produce a change of approximately
Last Answer : A change of 4% in the supply voltage to an induction motor will produce a change of approximately 8% in the rotor torque
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491 views
1 answer
asked
May 8, 2018
by
anonymous

The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be
Last Answer : The rotor impedance of a slip ring induction motor is (0.1 + j0.6)Ohm/ ph . The resistance/ph to be inserted into rotor to get maximum torque at starting should be 0.5 Ohm
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166 views
1 answer
asked
May 3, 2018
by
anonymous

In an induction motor if the flux density is reduced to one-half, of its normal value then the torque will (1) reduce to one-half (2) reduce to one-fourth (3) remain unchanged (4) increase four times
Last Answer : In an induction motor if the flux density is reduced.to one-half, of its normal value then the torque will reduce to one-fourth
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1 answer
asked
May 1, 2018
by
anonymous
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The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque (1) Decreases (2) Increases (3) Remains constant (4) None of the above
Last Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases
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238 views
1 answer
asked
May 1, 2018
by
anonymous

Torque developed by a three-phase, 400V, induction motor is 100 N -m. If the applied voltage is reduced to 200-V, the d'veloped torque will be
Last Answer : Torque developed by a three-phase, 400V, induction motor is 100 N -m. If the applied voltage is reduced to 200-V, the d'veloped torque will be 25 N -m
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431 views
1 answer
asked
Apr 29, 2018
by
anonymous
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