A 3-phase induction motor, 440-V, 50-Hz, 6-pole, delta-connected has the following equivalent-circuit parameters at normal frequency:RI=0.2 ohm, R'2=0.18 ohm, XI= x'2-0.58 ohm, all per phase values. (a) The machine is subjected in service to an occasional fall of 40% in both voltage and frequency. What total mechanical load torque is it safe to drive so that the machine just does not stall under these conditions? (b) When operating at normal voltage and frequency, calculate the speed when delivering this torque and the power developed. Calculate also the speed at which maximum torque occurs.
A 3-phase induction motor, 440-V, 50-Hz, 6-pole, delta-connected has the following equivalent-circuit parameters at normal frequency:RI=0.2 ohm, R'2=0.18 ohm, XI= x'2-0.58 ohm, all per phase values. (a) The machine is subjected in service to an occasional fall of 40% in both voltage and frequency. What total mechanical load torque is it safe to drive so that the machine just does not stall under these conditions? (b) When operating at normal voltage and frequency, calculate the speed when delivering this torque and the power developed. Calculate also the speed at which maximum torque occurs.
Introductory Circuit Analysis (13th Edition)
13th Edition
ISBN:9780133923605
Author:Robert L. Boylestad
Publisher:Robert L. Boylestad
Chapter1: Introduction
Section: Chapter Questions
Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...
Related questions
Question
![A 3-phase induction motor, 440-V, 50-Hz, 6-pole, delta-connected has the
following equivalent-circuit parameters at normal frequency:R1-0.2 ohm, R'2=0.18
ohm, XI= x'2=D0.58 ohm, all per phase values.
(a) The machine is subjected in service to an occasional fall of 40% in both voltage
and frequency. What total mechanical load torque is it safe to drive so that the
machine just does not stall under these conditions?
(b) When operating at normal voltage and frequency, calculate the speed when
delivering this torque and the power developed. Calculate also the speed at which
maximum torque occurs.
(c) If V and f were both halved, what would be the increase in starting torque from
the normal direct-on-line start at rated voltage and frequency?
(d) If now the machine is run up to speed from a variable-voltage, variable-
frequency supply, calculate the required terminal voltage and frequency to give the
'safe' torque calculated above: (i) at starting, (ii) at 500 rev/min.
(c) Repeat (d) for the machine to develop a torque equal to the maximum value
occurring at rated voltage and frequency. In both (d) and (e), the criteria is that the
air-gap flux per pole is maintained constant for any particular torque.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F50f9a936-e1fc-4bf8-b9e7-21edbde8d61b%2Fe48756fa-3223-424f-ae64-be6351573a18%2Fq513aod_processed.jpeg&w=3840&q=75)
Transcribed Image Text:A 3-phase induction motor, 440-V, 50-Hz, 6-pole, delta-connected has the
following equivalent-circuit parameters at normal frequency:R1-0.2 ohm, R'2=0.18
ohm, XI= x'2=D0.58 ohm, all per phase values.
(a) The machine is subjected in service to an occasional fall of 40% in both voltage
and frequency. What total mechanical load torque is it safe to drive so that the
machine just does not stall under these conditions?
(b) When operating at normal voltage and frequency, calculate the speed when
delivering this torque and the power developed. Calculate also the speed at which
maximum torque occurs.
(c) If V and f were both halved, what would be the increase in starting torque from
the normal direct-on-line start at rated voltage and frequency?
(d) If now the machine is run up to speed from a variable-voltage, variable-
frequency supply, calculate the required terminal voltage and frequency to give the
'safe' torque calculated above: (i) at starting, (ii) at 500 rev/min.
(c) Repeat (d) for the machine to develop a torque equal to the maximum value
occurring at rated voltage and frequency. In both (d) and (e), the criteria is that the
air-gap flux per pole is maintained constant for any particular torque.
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 3 steps with 3 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
![Introductory Circuit Analysis (13th Edition)](https://www.bartleby.com/isbn_cover_images/9780133923605/9780133923605_smallCoverImage.gif)
Introductory Circuit Analysis (13th Edition)
Electrical Engineering
ISBN:
9780133923605
Author:
Robert L. Boylestad
Publisher:
PEARSON
![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
![Programmable Logic Controllers](https://www.bartleby.com/isbn_cover_images/9780073373843/9780073373843_smallCoverImage.gif)
Programmable Logic Controllers
Electrical Engineering
ISBN:
9780073373843
Author:
Frank D. Petruzella
Publisher:
McGraw-Hill Education
![Introductory Circuit Analysis (13th Edition)](https://www.bartleby.com/isbn_cover_images/9780133923605/9780133923605_smallCoverImage.gif)
Introductory Circuit Analysis (13th Edition)
Electrical Engineering
ISBN:
9780133923605
Author:
Robert L. Boylestad
Publisher:
PEARSON
![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
![Programmable Logic Controllers](https://www.bartleby.com/isbn_cover_images/9780073373843/9780073373843_smallCoverImage.gif)
Programmable Logic Controllers
Electrical Engineering
ISBN:
9780073373843
Author:
Frank D. Petruzella
Publisher:
McGraw-Hill Education
![Fundamentals of Electric Circuits](https://www.bartleby.com/isbn_cover_images/9780078028229/9780078028229_smallCoverImage.gif)
Fundamentals of Electric Circuits
Electrical Engineering
ISBN:
9780078028229
Author:
Charles K Alexander, Matthew Sadiku
Publisher:
McGraw-Hill Education
![Electric Circuits. (11th Edition)](https://www.bartleby.com/isbn_cover_images/9780134746968/9780134746968_smallCoverImage.gif)
Electric Circuits. (11th Edition)
Electrical Engineering
ISBN:
9780134746968
Author:
James W. Nilsson, Susan Riedel
Publisher:
PEARSON
![Engineering Electromagnetics](https://www.bartleby.com/isbn_cover_images/9780078028151/9780078028151_smallCoverImage.gif)
Engineering Electromagnetics
Electrical Engineering
ISBN:
9780078028151
Author:
Hayt, William H. (william Hart), Jr, BUCK, John A.
Publisher:
Mcgraw-hill Education,