Description : 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
Answer :
The torque developed by any 3-phase induction motor at 0.8 p.u. slip is unstable torque
asked
Apr 28, 2018
by
anonymous
Description : 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
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
asked
May 1, 2018
by
anonymous
Description : A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for
Answer :
A 400 V, 50 Hz three-phase induction motor rotates at 1440 rpm on full -load. The motor is wound for 4 poles
asked
Apr 29, 2018
by
anonymous
Answer :
Capacitor start motor has high torque in starting
asked
Sep 13, 2017
by
anonymous
Answer :
Speed torque characteristic of a repulsion induction motor is similar to that of a D.C. compound motor.
asked
Mar 20, 2018
by
anonymous
Description : 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 resistance winding. (C) Small current flows through the outer high resistance winding. (D) Large current flows through the inner low resistance winding.
Answer :
In a double squirrel cage induction motor, good starting torque is produced as Large current flows through the outer high resistance winding.
asked
May 8, 2018
by
anonymous
Description : 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
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
asked
May 1, 2018
by
anonymous
Description : Explain the need and steps to conduct the reduced voltage running up test on the three phase induction motor.
asked
Apr 16, 2020
by
anonymous
Description : 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 the same direction (C) the flux increases and decreases in the opposite direction with the same magnitude (D) current flows through the rotor
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
asked
Apr 28, 2018
by
anonymous
Description : 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
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
asked
Apr 28, 2018
by
anonymous
Description : What is mean by plugging in three phase induction motor?
Answer :
Plugging in three-phase induction motor means interchanging of any two phases of a stator for quick stopping.
asked
Mar 3, 2018
by
anonymous
Answer :
In repulsion motor, maximum torque is developed when brush axis is at 45° electrical to the field axis.
asked
Mar 20, 2018
by
anonymous
Description : 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
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
asked
Apr 28, 2018
by
anonymous
Description : How is a three phase cage induction motor self starting?
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
asked
Mar 17, 2018
by
anonymous
Description : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is
Answer :
The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent
asked
Apr 29, 2018
by
anonymous
Description : speed control methods of three phase induction motor?
Answer :
Speed control of three phase induction motor
Answer :
Torque developed by a D.C. motor depends upon magnetic field, active length of the conductor, current flow through the conductors, number of conductors, radius of armature.
asked
Mar 20, 2018
by
anonymous
Answer :
The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.
asked
Mar 20, 2018
by
anonymous
Answer :
If starting winding of a single-phase induction motor is left in the circuit, it will draw excessive current and overheat.
asked
Mar 20, 2018
by
anonymous
Answer :
If a single phase induction motor runs slower than normal, the most likely defect is worn bearings.
asked
Mar 20, 2018
by
anonymous
Description : 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
Answer :
0
asked
Apr 28, 2018
by
anonymous
Answer :
Reason is kinetic energy
asked
Mar 20, 2018
by
anonymous
Description : A change of 4% in the supply voltage to an induction motor will produce a change of approximately
Answer :
A change of 4% in the supply voltage to an induction motor will produce a change of approximately 8% in the rotor torque
asked
May 8, 2018
by
anonymous
Answer :
The armature torque of the D.C. shunt motor is proportional to armature current.
asked
Mar 20, 2018
by
anonymous
Answer :
In case one phase of a three-phase synchronous motor is short-circuited the motor will not start.
asked
Mar 20, 2018
by
anonymous
Description : Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.
asked
Apr 16, 2020
by
anonymous
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 auxiliary winding lags the current in the main winding (C) both windings develop the same starting torque (D) both windings develop high starting current
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
asked
Apr 28, 2018
by
anonymous
Description : How does a single phase induction motor work?
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.
asked
Mar 17, 2018
by
anonymous
Description : Split phase induction motor
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.
Description : explain the working of single phase induction motor.
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.
asked
Oct 24, 2017
by
anonymous
Description : Single Phase Induction Motor
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.
Answer :
For the same H.P. rating and full load speed, following motor has poor starting torque differentially compounded.
asked
Mar 20, 2018
by
anonymous
Answer :
The torque produced in induction type relay (shaded pole structure) is inversely proportional to the square of the current.
asked
Mar 20, 2018
by
anonymous
Description : State any four advantages of three phase induction motor.
Answer :
Advantages of three phase induction motor https://youtu.be/27OIOCKN05U
asked
Jul 30, 2019
by
anonymous
Description : how can we reverse the direction of rotation of three phase induction motor ?
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.
asked
Oct 4, 2017
by
anonymous
Description : A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will?
Answer :
A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will not start at all.
asked
Mar 20, 2018
by
anonymous
Answer :
In case the back e.m.f. and the speed of a D.C. motor are doubled, the torque developed by the motor will remain unchanged.
asked
Mar 20, 2018
by
anonymous
Description : A balanced three phase star connected load is supplied from a three phase 400V 50 Hz supply. The resistance for per phase is 10 Ohm. Find the value of phase current, line current, power factor and total power consumed.
asked
Aug 12, 2018
by
anonymous
Answer :
In a D.C. series motor, if the armature current is reduced by 50%, the torque of the motor will be equal to 25% of the previous value.
asked
Mar 20, 2018
by
anonymous
Description : In a single-phase induction motor, the operating direction is determined by the ________ A) Rotor B) Stator C) Starting circuit D) None of these
Answer :
In a single-phase induction motor, the operating direction is determined by the Starting circuit
asked
Apr 29, 2018
by
anonymous
Answer :
The rotor slots, in an induction motor, are usually not quite parallel to the shaft because it helps in reducing the tendency of the rotor teeth to remain under the stator teeth.
asked
Mar 20, 2018
by
anonymous
Description : Is induction motor is self starting?
Answer :
Single phase induction motor is not self starting. Three phase induction motor is self starting.
asked
Mar 17, 2018
by
anonymous
Description : What is the definition of induction motor?
Answer :
its working on magnetic base made by coils and its work with 1 phase or 3 phase ac or dc supply
asked
Mar 17, 2018
by
anonymous
Description : What is the function of induction motor?
Answer :
while you give supply to motor its motor run on magnet base
asked
Mar 17, 2018
by
anonymous
Description : At which time power factor of the induction motor is low?
Answer :
The power factor of the inducction motor is low at the time of starting as compare to while the induction motor is running.
asked
Mar 3, 2018
by
anonymous
Answer :
Induction motor is a AC motor it is also known as asynchronous motor .
asked
Sep 9, 2017
by
anonymous
Answer :
if induction motor rotates exceed than its synchronous speed, it acts as a generator.
asked
Sep 9, 2017
by
anonymous
Description : Induction motor
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.
Description : In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is :
Answer :
In a 2 kW, 200 V, 1000 rpm. DC series motor the torque at full load was found to be 0.3 N -m. The torque at half full load in N -m is : 0.075
asked
Apr 29, 2018
by
anonymous
Description : Explain the working of a single phase capacitor start induction motor.
Answer :
Single phase capacitor start induction motor https://youtu.be/31lvvzU5Puc
asked
Jul 30, 2019
by
anonymous