Q4. A 415V, three phase, 50 Hz 4 pole, star connected induction motor ruins at 24 rev/s onfull load. The rotor resistance and reactance per phase are 0.35 ohms and rotor respectivelyand the effective rotor stator turns ratio is 0.85:1 calculate:a. The synchronous speedb. The slip.c. The full load torque.d. The power output if mechanical losses amount to 770 We. The maximum torquef. The speed at which maximum torque occursg. The starting torqueh. Direct on-line startingi. Star delta starting[20]

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Answered: Q4. A 415V, three phase, 50 Hz 4 pole,…

Delmar's Standard Textbook Of Electricity

7th Edition

ISBN:9781337900348

Author:Stephen L. Herman

Publisher:Stephen L. Herman

Chapter32: Three-phase Motors

Section: Chapter Questions

Problem 6RQ: Name three factors that determine the torque produced by an induction motor.

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Similar questions

L-1). The 3-phase wound-rotor induction motor has .... . a) high starting torque b) low starting current c) both "a" and "b" d) neither "a" nor "b" L-2). The 3-phase wound-rotor induction.........a) motor has a wire wound rotor b) motor's rotor can be connected to an external resistive load by way of slip rings and brushes c) motor requires more maintenance than the 3-phase squirrel-cage induction motor d) all of the above L-3). The 3-phase wound-rotor induction motor's rotor circuit's resistance should be adjusted so it is__________ during starting. a) low b) high c) either "a" or "b" d) neither "a" nor "b" L-4). Will a 3-phase wound-rotor induction motor start with no external circuit connected to its rotor leads? a) yes b) no
A three –phase, 440V, 50 Hz, 6 – pole induction motor running at 950 rpm takes 50 kW at certain load. The friction and windage loss is 1.5 kW and the stator losses = 1.2 kW. Determine the output from the rotor. (a). 42.68 kW (b). 46.48 kW (c). 48.80 kW (d). 44. 86 kW
A 3 – phase induction motor has a 4 – pole, star – connected stator winding. The motorruns on a 50 – Hz supply with 200 V between lines. The rotor resistance and standstillreactance power phase are 0.1 and 0.9 ohm respectively. The ratio of rotor to stator turnsis 0.67. Calculate (a) total torque at 4 % slip, (b) total mechanical power at 4 % slip, (c)maximum torque, (d) speed at maximum torque, (e) maximum m power
3.An induction motor has a rotor resistance and reactance at standstill of 0.1 ohm and 3.5 ohm respectively. At standstill the voltage induced to the rotor is 60volts per phase. If the slip is 5%, determine the rotor current
Three Phase Induction Mot... The relative speed of stator magnetic field with respect to rotor of a 30 induction motor with 4 pole, 50 Hz frequency. If the slip is 0.05.
6- Which of the following supply is given to the rotor winding of 3-Phase Induction Motor: a) DC Supply b) AC Supply c) No Supply d) Pulsating Supply 7- 3-Phase Induction Motor will have Starting Torque and Starting Current a) High, High b) Low, Low. c) High, Low d) Low, High 8- Which of the following method is used for controlling the speed of an induction motor: a) Changing number of stator poles b) Supply voltage control c) Frequency control d) All the options are correct 9- Which of the following method cannot be used for starting of 3-Phase Squirrel Induction Motor: a) Star-Delta Starting b) Line resistor startling c) transformer Starter d) Rotor Resistance Starting 10- The rotor of a stepper motor has no: a) windings b) commutator c) brushes d) all of the above
A value of magnetizing current in a 3-phase induction motor * gives power factor smaller .. larger smaller. .poor large . better O large...poor O
A 6-pole, 3-phase, 50 Hz induction motor develops a maximum torque of 30 Nm at 960 r.p.m. Determine the torque exerted by the motor at 5% slip. The rotor resistance per phase is 0.6ohm.
4) It is advisable to avoid line-starting of induction motor and use starter because: A. motor takes five to seven times its full load current B. it will pick-up very high speed and may go out of step C. it will run in reverse direction D. starting torque is very high E. starting speed is very high 5) In a three-phase induction motor, the number of poles in the rotor winding is always: A. zero B. more than the number of poles in stator C. less than number of poles in stator D. equal to number of poles in stator E. two 6) DOL starting of induction motors is usually restricted to: A. low horsepower motors B. variable speed motors C. high horsepower motors D. high speed motors A. variable torque motors
3. A 440V 60-hp six pole 60 hz A connected induction motor has the following parameters R1=0.048 R2= 0.035 Xm= 9.50 X1= 0.33 0 X2= 0.37 0 Pcore= 600W PF&W= 350W Use the Thevenin's Equivalent circuit concept to find: (a)Vth and Zth seen by the rotor circuit (b)The slip at which maximum torque occurs (c) the value of Max/pullout Torques (d) The starting torque.
A single-phase, 120 V, 60 Hz, four-pole, split-phase induction motor has the following standstill impedances:Main winding: Zm =5+j6.25Auxiliary winding: Za =8+j6a) Determine the value of capacitance to be added in series with the auxiliary winding to obtainmaximum starting torque.b) Compare the starting torques and starting current with and without the added capacitance in theauxiliary winding circuit when operated from a 120V, 60Hz supply
A wound rotor, induction motor has a rotor resistance of 0.6 ohms per phase and a rotor leakage reactance of 8 ohms.a)What is the operating speed (rpm) of this 2-pole induction motor fed from a 50Hz supply if the slip is 5%?b)If maximum torque occurs when R2 = sX2, what is the slip at maximum torque?c)What resistance must be added to the rotor circuit to give maximum startingtorque?

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