A three phase induction motor designed for a rated voltage of V1 at 50 Hz is accidentally switched on directly to a voltage of V2 at 60 Hz. Stator impedance of the motor is negligible. Calculate the ratios of currents and torques at starting and maximum torques when V2 = V1. Also find the ratio of V2 to V1 to obtain the same values of starting current and torque at 60 Hz. (Ans: 0.834, 0.695, 0.695, ;

A three phase induction motor designed for a rated voltage of V1 at 50 Hz is accidentally switched on directly to a voltage of V2 at 60 Hz. Stator impedance of the motor is negligible. Calculate the ratios of currents and torques at starting and maximum torques when V2 = V1. Also find the ratio of V2 to V1 to obtain the same values of starting current and torque at 60 Hz. (Ans: 0.834, 0.695, 0.695, ;

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.

See similar textbooks

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
Derive the torque equation for a three phase induction motor, with the help of torque speed characteristics curve briefly explain how an induction motor can operate in stable region.
B/ Fill in the blanks: TV ezur 1- In a three-phase induction motor iron losses in stator will be..... that in rotor. 2- In three-phase induction motors sometimes copper bars are placed deep in the rotor to........... 3- Blocked rotor test on induction motors is used to find out. R..., ke, X. 4- The maximum torque in an induction motor depends on .............and .....
Torque-speed characteristics for three phase induction motor 4. Discuss the following (rated torque, starting torque, break down torque).
A four-pole induction motor drives a load at 2500 rpm. This is to be accomplished by using an electronic converter to convert a 400-V dc source into a set of three-phase ac voltages. Find the frequency required for the ac voltages assuming that the slip is 4 percent. The load requires 2 hp. If the dc-to-ac converter has a power efficiency of 88 percent and the motor has a power efficiency of 80 percent, estimate the current taken from the dc source.
200 +21. If maximum torque of an induction motor is kg-m at a slip of 12%, the torque at 6% slip would be...... kg-m. 1 (a) 100 (b) 160 (c) 50 (d) 40 B, 1993)
A 4-pole induction motor drives a load at 2500 rpm. This is to be accomplished by using an electronic converter to convert 400 Volts DC into a set of 3-phase AC voltages. Find the frequency required for the AC voltages assuming that the slip is 4 percent. The load requires 2 hp. If the DC-to-AC converter has a power efficiency of 88 percent and the motor has a power efficiency of 80 percent, estimate the current taken from the DC source.
Design and develop equivalent circuit model of a single phase Induction motor with th consideration of core losses present with the parameter consideration of stator resistance R1 and reactance X1 and two rotor parameters which includes r2,x2 and magnetising reactance xm. (Illustration is required) Draw by hand please
An 3-phase induction motor(IM) has full load slip = 0.5%. If the rotor circuit resistance is increased so that R2new =2R2old, then the slip at which the motor develops the same full load torque is=.. * ......
Design a DC motor circuit to drive A fan-type load with a torque equation equal to: TL=1.34×10−7ω2TL=1.34×10−7ω2 N.m The fan speed range is from 500 to 1200 rpm. To achieve the required operation, the armature voltage of the motor is adjusted by a single-phase, full-wave, ac/dc converter. The input voltage and frequency to the converter are 480 V (rms) and 50 Hz. choose the motor type, show the motor rating, αα range, Supply voltage, and frequency, and any required other information Modify the design to automatically adjust the voltage drive the load within the specified speed range. show the control variable, controller type, connection, and controller weights.
Design a DC motor circuit to drive A fan-type load with a torque equation equal to: TL=1.34×10−7ω2TL=1.34×10−7ω2 N.m The fan speed range is from 500 to 1200 rpm. To achieve the required operation, the armature voltage of the motor is adjusted by a single-phase, full-wave, ac/dc converter. The input voltage and frequency to the converter are 480 V (rms) and 50 Hz. choose the motor type, show the motor rating, αα range, Supply voltage, and frequency, and any required other information Modify the design to automatically adjust the voltage drive the load within the specified speed range. show the control variable, controller type, connection, and controller weights. design the single-phase, full-wave, ac/ dc converter. show design specifications, the reason for DC motor selection. correct manual circuit, and correct automatic closed-loop control circuit
2. Describe the Torque-Slip characteristics of a three phase induction motor.