Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 25, Problem 5SQ
When the voltage is reduced to start a motor, what happens to the
a. torque?
b. current?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Identify the type of motor used in Washing Machine. With a neat sketch explain its working. List it's advantages and disadvantages.
Q51
Which NEC table is used to determine the full-load current of a torque motor?
Select one:
A. NEC TABLE 430.6(B)
B. NEC TABLE 430.7(B)
C. NEC TABLE 430.24
D. NEC TABLE 430.22
5. WHAT IS A "TORQUE"?
6. CITE THE DIFFERENT FORMULAS INVOLVED IN THE OPERATION OF DC MOTOR.
7. EXPLAIN THE POWER STAGES WHEN THE DC MOTOR UNDER OPERATIONS
8. PROVE THAT A CAPACITY OF DC MOTOR, 1HP = 746 Watt
Chapter 25 Solutions
Electric Motor Control
Ch. 25 - Prob. 1SQCh. 25 - When can full-voltage starting be used?Ch. 25 - Name the simplest, most rugged, and most reliable...Ch. 25 - Define the term slip.Ch. 25 - When the voltage is reduced to start a motor, what...Ch. 25 - Why is it more advisable to start some machines at...Ch. 25 - Prob. 7SQCh. 25 - Prob. 8SQCh. 25 - Prob. 9SQCh. 25 - Prob. 10SQ
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.Similar questions
- A motor is operating a load that requires a torque of 750 lb-in. and is turning at a speed of 1575 RPM. How much hp is the motor producing?arrow_forwardFill in the following blanks 1. the ________ is simplest type of all electrical machines 2. the ________ motor works based on variable reluctance principle 3. the direction of torque for SRM motor is function of the _________ 4. The ________ motor is similar an ordinary d.c. shunt motorarrow_forwardState the correct terminology used to describe each of the following 1.the current drawn by a motor at standstill with the rate voltage and frequency applied. 2.the twisting or turning force of a motor . 3.the deference in speed between the motion and the rotation of the rotor shaft. 4.a device that provides and adjustable time period to perform a function.arrow_forward
- Explain how does the current will be reduced during the starting of the motor.arrow_forwardBelow is a diagram of a DC motor and the mechanical load connected to it. Which statement is wrong? A. The speed of the motor ea increases with increasing B. The torque of the motor increases with increasing ia C. eb increases and speed decreases D. if increasing. the torque of the motor increases E. Nonearrow_forward29) A 415 V Shunt motor takes a total current of 80 A . if the shunt field resistance is 40 ohms, the armature resistance is 0.25 ohms, and iron, friction, and windage losses amount to 1.5 kW, Determine I) Armature copper loss II) Field copper loss III) Total loss IV) Output power V) overall efficiency of the motor.arrow_forward
- EE 422 - AC and DC Machinery Solve the following problems completely. Box and Round-off your final answer in nearesttwo decimal places 1.A 25 hp,250V long shunt compound motor takes 5 A when running light and runs at 1150 rpm. Armature resistance, 0.15 ohm, Shunt field resistance, 200 ohm and series field resistance, 0.05 ohm. At rated load the motor takes 86.5A and runs at 720 rpm. Determine the ratio of torque developed from no-load to full load. answer: 1:34 2.A compound motor develops a torque of 271 lb-ft when it is operating at 1200 rpm, under which condition its armature current Ia is 215 amperes. What will be the developed horsepower of the motor if the load is increased so that it slows down to 1,1120 rpm in which case Ia changes to 238 amperes and the total flux increases by 8 percent? answer: 69.1hparrow_forward20. What is the effect of applying a lower-than-rated voltage to a fractional-horsepower motor?A. The motor will operate with increased magnetizing current.B. The motor will operate satisfactorily at 95% of the rated voltage.C. The motor will heat up dangerously.arrow_forwardANSWERE FAST PLEASE QUESTION from book ELECTRIC MACHINE-1 LAB BASESD QUESTION Answer precisely keeping in view the experiments performed with the equipment in the lab.i. You are working with the DC motor and the motor is accelerating. Suggest a way that canoptimally control the speed of the motor. Explain the method and how it is a better way.ii. What type of DC motor should be used when the load connected requires a higher starting torque?Precisely explain and draw the relevant circuit.iii. What will happen to a DC series motor if the load is suddenly thrown off the motor? You canexplain with any mathematical reasoning.iv. What effect will the load have on a DC shunt motor with significantly high armature resistance?v. For the four-point DC starter kit, what will happen if the series resistances are connected in reverseorder. Draw and explain how this combination is better than the 3 points started.arrow_forward
- A 500 V, lap wound d.c. A shunt motor has 90 slots and each has 8 conductors. When the motor delivers full load it draws a current of 30/ A from the line. The field and armature resistances are 250 ohm and 0.4 ohm respectively. If the fixed resistance is 27.1 mWh, find the speed of the motor and the torque produced.arrow_forwardA 250 V shunt motor, having an armature resistance of 0.2 ohm draws fromthe mains a current of 50 A on half full load. The speed is to beincreased to twice half full load speed. If the torque of the motor is ofconstant magnitude, determine the percentage change in flux required.[Ans. 52.29] I WANT A DIFFRENT APPROACH (NOT COPY PASTE ON LIBRARY)arrow_forwardDifferentiate a “Generator” from a “Motor” in terms of principle of operation. please answer clearly and readable. Thank you.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Electricity for Refrigeration, Heating, and Air C...Mechanical EngineeringISBN:9781337399128Author:Russell E. SmithPublisher:Cengage Learning
Delmar's Standard Textbook Of ElectricityElectrical EngineeringISBN:9781337900348Author:Stephen L. HermanPublisher:Cengage Learning
Electricity for Refrigeration, Heating, and Air C...
Mechanical Engineering
ISBN:9781337399128
Author:Russell E. Smith
Publisher:Cengage Learning
Delmar's Standard Textbook Of Electricity
Electrical Engineering
ISBN:9781337900348
Author:Stephen L. Herman
Publisher:Cengage Learning
Power vs Torque - In Depth Explanation and Mythbusting; Author: kyle.Engineers;https://www.youtube.com/watch?v=X7KWtf4wqN4;License: Standard Youtube License