Testbook Logo
Exams SuperCoaching Test Series Skill Academy
More

Question

Download Solution PDF

The locked rotor in a 3 phase star connected 15 kW 4 pole 230 V 50 Hz IM runs at rated conditions of 50A. Neglecting losses and magnetising current the approximate locked rotor line current drawn when the motor is connected to 236 V 57 Hz is

This question was previously asked in
GATE EE 2012 Official Paper
Attempt Online
View all GATE EE Papers >

  1. 58.5A

  2. 45.0A

  3. 45.7A

  4. 55.6A

Answer (Detailed Solution Below)

Option 2 :

45.0A
Free Tests
View all Free tests >
Free
GATE EE 2023: Full Mock Test
5.5 K Users
65 Questions 100 Marks 180 Mins
Start Now

Detailed Solution

Download Solution PDF

\(\begin{array}{l} {I_{se}} = \frac{V}{{{X_{se}}}}\ \alpha\ \frac{v}{f}\\ \therefore {I_{se}}\ nw = 50 \times \frac{{236}}{{230}} \times \frac{{50}}{{57}}\\ = 45A \end{array}\)

Download Solution PDF
Latest GATE EE Updates

Last updated on Feb 19, 2024

-> GATE EE 2024 Answer Key has been released.

-> The exam was held on 3rd, 4th, 10th and 11th February 2024. 

-> Candidates preparing for the exam can refer to the GATE EE Important Questions to improve their preparation for the exam and increase their chances of selection.

-> Candidates must take the GATE EE mock tests to improve their performance.

-> Practice GATE EE Previous Year Papers to kickstart preparation for the upcoming cycle. 

More Induction Motor Rotor Frequency Questions

Q1.A 3 - phase, 20 HP, 208 V, 60 Hz, 6 - pole star connected induction motor delivers 15 kW at a slip of 5%. Find the frequency of the rotor current.
Q2.A three-phase 20 HP. 208 V, 60 Hz, 6 - pole, star - connected induction motor delivers 15 kW at 5% slip. Calculate the frequency of the rotor current.
Q3.When the rotor of a three-phase induction motor runs at synchronous speed, its rotor frequency will become-
Q4.A 3 phase induction motor runs at almost 1000 rpm at no load and 950 rpm at full load when supplied with power from a 50 Hz 3 phase line. The frequency of rotor voltage is:
Q5.The stator of a 415V, 50 Hz, 4-pole slip ring Induction Motor is excited by rated frequency with slip rings open circuited. The rotor is made to rotate at a speed of 600 rpm in the opposite direction to the normal direction, The frequency of induced voltage across slip ring is
Q6.A 500 HP, 440 V, 3-phase, 50 Hz induction motor runs at 950 r.p.m. when on full load with a synchronous speed of 1000 r.p.m. For this condition, the frequency of the rotor current will be
Q7.A 3 phase induction motor runs at almost 1000 rpm at no load and 950 rpm at full load when supplied with power from a 50 Hz 3 phase line. The frequency of rotor voltage is:
Q8.The locked rotor in a 3 phase star connected 15 kW 4 pole 230 V 50 Hz IM runs at rated conditions of 50A. Neglecting losses and magnetising current the approximate locked rotor line current drawn when the motor is connected to 236 V 57 Hz is
Q9.The speed of a 4 pole induction motor is controlled by varying the supply frequency while maintaining ratio of Voltage to frequency constant(V/f). At rated frequency of 50Hz and rated voltage of 400 V its speed is 1440 rpm. Find the speed at 30 Hz, If the load torque remains constant.

More Three Phase Induction Motor Questions

Q1.A three-phase induction motor is operating at a slip of 0.05 at full load. During the run, if the phase sequence of the supply is reversed, then what is the slip at the instant of reversal?
Q2.A three-phase, 440 V, 6 pole, slip ring induction motor operates with 2% slip and takes a stator current of 50 A. The speed of the motor is reduced at constant torque to 500 rpm using stator voltage control. The new value of the stator current will be _________.
Q3.A 400 V, 50 Hz, three-phase induction motor runs at a slip of 0.06 when it is driving a constant load torque. With what slip will it run driving the same load if the voltage applied is reduced to 200 V, neglecting stator resistance and the equivalent reactance of the motor?
Q4.At what value of brush shift angle, the torque produced by the repulsion motor is maximum?
Q5.On which of the following parameter, the maximum torque of a three phase induction motor does not depend?
Q6.At start, the maximum value of slip for a three phase induction motor is ________.
Q7.Why starters are required in induction motors?
Q8.An induction machine has 4 poles and is operating at a speed of 1475 rpm and 50 Hz frequency. The machine is operating at a slip of ___________.
Q9.If the supply voltage becomes half of its initial value, the torque delivered by a three phase induction motor _____________.
Q10.The rotor voltage of a slip-ring induction motor gives 120 oscillations per minute when the motor is connected to 3-phase, 50 Hz supply. The percentage slip of the rotor is
Suggested Test Series
View All >
GATE Mathematics & General Aptitude (Common for All) Test Series
92 Total Tests with 0 Free Tests
Start Free Test
GATE EE 2023-24 Test Series
166 Total Tests with   1 Free Tests
Start Free Test

More Electrical Machines Questions

Q1.An 8-pole alternator is driven by a turbine at a speed of 1200 rpm. What is the frequency of EMF generated?
Q2.A 10-pole, three-phase, 50 Hz alternator has 180 slots. If the armature coils are short-pitched by two slots, what is the pitch factor?
Q3.ADC separately excited, 4 pole, lap wound generator supplies an armature current of 100 A. What is the current per parallel path?
Q4.A single-phase capacitor start motor has a starting winding of reactance of 6 Ω takes a current at a phase angle of 45°. What must be the capacitive reactance of the capacitor to get the maximum starting torque?
Q5.Open circuit and short circuit tests conducted on a 10 kVA 2000 V/200 V, 50Hz single-phase transformer gave the following readings. OC test: 200 V, 1.1 A, 81 W SC test: 30 V, 5 A, 100 W At what fraction of full load will the transformer operate at maximum efficiency?
Q6.A single-phase transformer has a turn ratio of 2. The respective resistances of LV and HV windings are 0.06 Ω and 0.2 Ω. What is the total equivalent resistance of the transformer referred to the LV side?
Q7.A three-phase induction motor is operating at a slip of 0.05 at full load. During the run, if the phase sequence of the supply is reversed, then what is the slip at the instant of reversal?
Q8.It is intended to measure the resistance of the series field winding of a DC series motor accurately. Which is the most suitable method?
Q9.If the constant loss of a generator is 1600 W and armature resistance is 1 Ω, what is the current corresponding to maximum efficiency?
Q10.A three-phase, 440 V, 6 pole, slip ring induction motor operates with 2% slip and takes a stator current of 50 A. The speed of the motor is reduced at constant torque to 500 rpm using stator voltage control. The new value of the stator current will be _________.
Important Links for GATE Exam
Super Coaching
Branch wise Page
Test Series
Previous Year Papers
Testbook Edu Solutions Pvt. Ltd.
1st & 2nd Floor, Zion Building,
Plot No. 273, Sector 10, Kharghar,
Navi Mumbai - 410210
[email protected]
Toll Free:1800 833 0800
Office Hours: 10 AM to 7 PM (all 7 days)
Company
About usCareers We are hiringTeach Online on TestbookPartnersMediaSitemap
Products
Test SeriesTestbook PassOnline CoursesOnline VideosPracticeBlogRefer & EarnBooks
Our Apps
Follow us on
Copyright © 2014-2022 Testbook Edu Solutions Pvt. Ltd.: All rights reserved
User PolicyTermsPrivacy
Get Free Access Now
Hot Links： teen patti boss master teen patti teen patti master old version teen patti party