In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then (A) the flux is constant (B) the flux first decreases and then increases in ... increases and decreases in the opposite direction with the same magnitude (D) current flows through the rotor
Last Answer : In a single-phase induction motor when the rotor is stationary and voltage is applied to the stator, then the flux first decreases and then increases in the same direction
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Apr 28, 2018
by
anonymous

A 3-phase, 4-pole, 50Hz induction motor runs at a speed of 1440 rpm. The rotating field produced by the rotor rotates at a speed of ________ rpm with respect to stator field. (A) 1500 (B) 0 (C) 1440 (D) 60
Last Answer : 0
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2.0k views
2 answers
asked
Apr 28, 2018
by
anonymous
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An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is (A) 5.06 kW (B) 0.3 kW (C) 100 kW (D) 83.33 kW
Last Answer : An 8-pole, 50Hz, three-phase induction motor is running at 705rpm and has a rotor copper loss of 5kW. Its rotor input is 83.33 kW
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179 views
1 answer
asked
Apr 28, 2018
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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131 views
0 answers
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Apr 16, 2020
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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165 views
1 answer
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May 3, 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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230 views
1 answer
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Sep 20, 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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136 views
1 answer
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May 8, 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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467 views
1 answer
asked
May 8, 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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371 views
1 answer
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May 1, 2018
by
anonymous

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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234 views
1 answer
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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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422 views
1 answer
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Apr 29, 2018
by
anonymous
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The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is
Last Answer : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent
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361 views
1 answer
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Apr 29, 2018
by
anonymous

A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for
Last Answer : A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for 4 poles
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304 views
1 answer
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Apr 29, 2018
by
anonymous

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
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106 views
1 answer
asked
Apr 28, 2018
by
anonymous

The torque developed by any 3-phase induction motor at 0.8 p.u. slip is (A) Full-load torque (B) unstable torque (C) starting torque (D) break down
Last Answer : The torque developed by any 3-phase induction motor at 0.8 p.u. slip is unstable torque
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3.1k views
1 answer
asked
Apr 28, 2018
by
anonymous

In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is (A) 0.2 Ω (B) 0.3 Ω (C) 0.4 Ω (D) 0.5 Ω
Last Answer : In a 3-phase slip-ring induction motor, the slip at some speed is 0.05. The speed is reduced by inserting an external resistance in the rotor circuit and the slip is 0.15. If the rotor winding resistance per phase is 0.2 Ω, the external resistance is 0.3 Ω
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165 views
1 answer
asked
Apr 28, 2018
by
anonymous

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

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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234 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : If a single phase induction motor runs slower than normal, the most likely defect is worn bearings.
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170 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Speed torque characteristic of a repulsion induction motor is similar to that of a D.C. compound motor.
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164 views
1 answer
asked
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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158 views
1 answer
asked
Mar 17, 2018
by
anonymous

How does a single phase induction motor work?
Last Answer : As we know that single phase induction is not self started because for self started we require atleast two revolving field but single phase induction motor has only one. So we provide extra ... 1phase IM classified as split phase IM, capacitor start capacitor run, capacitor start induction run.
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124 views
1 answer
asked
Mar 17, 2018
by
anonymous
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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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111 views
1 answer
asked
Mar 17, 2018
by
anonymous
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What is the definition of induction motor?
Last Answer : its working on magnetic base made by coils and its work with 1 phase or 3 phase ac or dc supply
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123 views
1 answer
asked
Mar 17, 2018
by
anonymous

What is the function of induction motor?
Last Answer : while you give supply to motor its motor run on magnet base
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158 views
1 answer
asked
Mar 17, 2018
by
anonymous

At which time power factor of the induction motor is low?
Last Answer : The power factor of the inducction motor is low at the time of starting as compare to while the induction motor is running.
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150 views
1 answer
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Mar 3, 2018
by
anonymous

What is mean by plugging in three phase induction motor?
Last Answer : Plugging in three-phase induction motor means interchanging of any two phases of a stator for quick stopping.
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153 views
1 answer
asked
Mar 3, 2018
by
anonymous

explain the working of single phase induction motor.
Last Answer : Stator has two winding namely main winding and auxiliary winding.when single phase ac supply is given to the motor,its produces alternating field.this field cut by a cage rotor.so some emf ... due to this emf,rotor flux produced.the interaction between two fluxes produce torque.so rotor rotates.
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1 answer
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Oct 24, 2017
by
anonymous

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

Last Answer : Induction motor is a AC motor it is also known as asynchronous motor .
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98 views
1 answer
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Sep 9, 2017
by
anonymous

Last Answer : if induction motor rotates exceed than its synchronous speed, it acts as a generator.
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67 views
1 answer
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Sep 9, 2017
by
anonymous

Induction motor
Last Answer : Induction Motor Inductor is a coil of wire which possess the property of inductance. Inductance is the property of an electric conductor which generate electromotive force (EMF ... motor are classified as slip ring induction motor and squirrel cage induction motor.
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1 answer
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Aug 9, 2017
by
anonymous

Single Phase Induction Motor
Last Answer : Single Phase Induction Motor Single phase induction motor is mostly used in home, office, shop and many single phase appliances like pumps, ... torque and silent operation. It is uses where silent operation is required.
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528 views
1 answer
asked
Aug 9, 2017
by
anonymous

speed control methods of three phase induction motor?
Last Answer : Speed control of three phase induction motor
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2 answers
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Aug 9, 2017
by
anonymous

Last Answer : Single phase induction motor usually operates on 0.6 power factor lagging.
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126 views
1 answer
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Mar 20, 2018
by
anonymous

Last Answer : The power factor of a single-phase induction motor is usually lagging.
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189 views
1 answer
asked
Mar 20, 2018
by
anonymous
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Last Answer : The repulsion-start induction-run motor is used because of high starting torque.
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89 views
1 answer
asked
Mar 20, 2018
by
anonymous

Basic electrical engineering
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12 views
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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584 views
1 answer
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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
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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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220 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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1.1k 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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264 views
2 answers
asked
Apr 27, 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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218 views
0 answers
asked
Apr 16, 2020
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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3 answers
asked
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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59 views
1 answer
asked
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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394 views
2 answers
asked
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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137 views
2 answers
asked
Jul 30, 2019
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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690 views
1 answer
asked
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
1 answer
asked
Sep 22, 2018
by
anonymous
