A three phase induction motor designed for a rated voltage of Vi at 50 Hz is accidentally switched on directly to a voltage of V2at 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 V2to Vi to obtain the same values of starting current and torque at 60 Hz. (Ans: 0.834, 0.695, 0.695, ; 1.2)
A three phase induction motor designed for a rated voltage of Vi at 50 Hz is accidentally switched on directly to a voltage of V2at 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 V2to Vi to obtain the same values of starting current and torque at 60 Hz. (Ans: 0.834, 0.695, 0.695, ; 1.2)
Delmar's Standard Textbook Of Electricity
7th Edition
ISBN:9781337900348
Author:Stephen L. Herman
Publisher:Stephen L. Herman
Chapter35: Harmonics 916
Section: Chapter Questions
Problem 3RQ: Would a positive-rotating harmonic or a negative-rotating harmonic be more harmful to an induction...
Related questions
Question
![15. A three phase induction motor designed for a rated voltage of Vi at 50 Hz is
accidentally switched on directly to a voltage of V2at 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 V2to Vi to
obtain the same values of starting current and torque at 60 Hz. (Ans: 0.834,
0.695, 0.695, ; 1.2)](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6be2b1b7-4581-4ba9-bd65-5870b6a432f7%2F2c9697a1-c072-4f6e-bc1e-b24005ae40b7%2Fmckiads_processed.jpeg&w=3840&q=75)
Transcribed Image Text:15. A three phase induction motor designed for a rated voltage of Vi at 50 Hz is
accidentally switched on directly to a voltage of V2at 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 V2to Vi to
obtain the same values of starting current and torque at 60 Hz. (Ans: 0.834,
0.695, 0.695, ; 1.2)
![14. An 8 pole 50 Hz, three phase induction motor runs at a speed of 720 rpm
when delivering full load torque. Its stand still rotor resistance and reactance
are 0.1 ohm and 0.6 ohm per phase respectively. An additional resistance of
0.5 ohm per phase is inserted in the rotor circuit to control the speed.
Calculate the speed at which the motor runs now with full load torque
remaining the same. (Ans: 570 rpm)](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6be2b1b7-4581-4ba9-bd65-5870b6a432f7%2F2c9697a1-c072-4f6e-bc1e-b24005ae40b7%2Flnprjui_processed.jpeg&w=3840&q=75)
Transcribed Image Text:14. An 8 pole 50 Hz, three phase induction motor runs at a speed of 720 rpm
when delivering full load torque. Its stand still rotor resistance and reactance
are 0.1 ohm and 0.6 ohm per phase respectively. An additional resistance of
0.5 ohm per phase is inserted in the rotor circuit to control the speed.
Calculate the speed at which the motor runs now with full load torque
remaining the same. (Ans: 570 rpm)
Expert Solution
![](/static/compass_v2/shared-icons/check-mark.png)
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 6 steps with 5 images
![Blurred answer](/static/compass_v2/solution-images/blurred-answer.jpg)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Recommended textbooks for you
![Delmar's Standard Textbook Of Electricity](https://www.bartleby.com/isbn_cover_images/9781337900348/9781337900348_smallCoverImage.jpg)
Delmar's Standard Textbook Of Electricity
Electrical Engineering
ISBN:
9781337900348
Author:
Stephen L. Herman
Publisher:
Cengage Learning
![Delmar's Standard Textbook Of Electricity](https://www.bartleby.com/isbn_cover_images/9781337900348/9781337900348_smallCoverImage.jpg)
Delmar's Standard Textbook Of Electricity
Electrical Engineering
ISBN:
9781337900348
Author:
Stephen L. Herman
Publisher:
Cengage Learning