Physics for Scientists and Engineers with Modern, Revised Hybrid (with Enhanced WebAssign Printed Access Card for Physics, Multi-Term Courses)
9th Edition
ISBN: 9781305266292
Author: Raymond A. Serway, John W. Jewett
Publisher: Cengage Learning
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Chapter 31, Problem 48P
(a)
To determine
The back emf generated by the motor.
(b)
To determine
The rate at which the internal energy is produced in the windings.
(c)
To determine
The rate at which the internal energy is produced in the windings when shaft of the motor stops rotating.
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A dc motor with its rotor and field coils connected in series has an internalresistance of 2.00 Ω. When running at full load on a 120 V line, itdraws a 4.00 A current. What is the motor’s efficiency?
A dc motor with its rotor and field coils connected in serieshas an internal resistance of 3.2 Ω. When the motor is running at fullload on a 120 V line, the emf in the rotor is 105 V. What is the current drawn by the motor from the line?
A motor in normal operation carries a direct current of 0.750 A when connected to a 120 V power supply. The resistance in the motor windings is 17.2 . Determine the following values.
(a) While in normal operation, what is the back emf generated by the motor?
(b) While in normal operation, at what rate is internal energy produced in the windings?
(c) What If? Suppose that a malfunction stops the motor shaft from rotating. At what rate will internal energy be produced in the windings in this case in kW (Most motors have a thermal switch that will turn off the motor to prevent overheating when this occurs.)
Chapter 31 Solutions
Physics for Scientists and Engineers with Modern, Revised Hybrid (with Enhanced WebAssign Printed Access Card for Physics, Multi-Term Courses)
Ch. 31.1 - A circular loop of wire is held in a uniform...Ch. 31.2 - QUICK QUIZ 30.2 In Figure 30.8a, a given applied...Ch. 31.3 - Figure 30.12 (Quick Quiz 30.3) QUICK QUIZ 30.3...Ch. 31.5 - Prob. 31.4QQCh. 31.6 - Prob. 31.5QQCh. 31 - Prob. 1OQCh. 31 - Prob. 2OQCh. 31 - Prob. 3OQCh. 31 - Prob. 4OQCh. 31 - Prob. 5OQ
Ch. 31 - Prob. 6OQCh. 31 - Prob. 7OQCh. 31 - Prob. 8OQCh. 31 - Prob. 9OQCh. 31 - Prob. 10OQCh. 31 - Prob. 11OQCh. 31 - Prob. 1CQCh. 31 - Prob. 2CQCh. 31 - Prob. 3CQCh. 31 - Prob. 4CQCh. 31 - Prob. 5CQCh. 31 - Prob. 6CQCh. 31 - Prob. 7CQCh. 31 - Prob. 8CQCh. 31 - Prob. 9CQCh. 31 - Prob. 10CQCh. 31 - Prob. 1PCh. 31 - Prob. 2PCh. 31 - Prob. 3PCh. 31 - Prob. 4PCh. 31 - Prob. 5PCh. 31 - Prob. 6PCh. 31 - Prob. 7PCh. 31 - Prob. 8PCh. 31 - Prob. 9PCh. 31 - Scientific work is currently under way to...Ch. 31 - Prob. 11PCh. 31 - Prob. 12PCh. 31 - Prob. 13PCh. 31 - Prob. 14PCh. 31 - Prob. 15PCh. 31 - Prob. 16PCh. 31 - A coil formed by wrapping 50 turns of wire in the...Ch. 31 - Prob. 18PCh. 31 - Prob. 19PCh. 31 - Prob. 20PCh. 31 - Prob. 21PCh. 31 - Prob. 22PCh. 31 - Prob. 23PCh. 31 - A small airplane with a wingspan of 14.0 m is...Ch. 31 - A 2.00-m length of wire is held in an eastwest...Ch. 31 - Prob. 26PCh. 31 - Prob. 27PCh. 31 - Prob. 28PCh. 31 - Prob. 29PCh. 31 - Prob. 30PCh. 31 - Prob. 31PCh. 31 - Prob. 32PCh. 31 - Prob. 33PCh. 31 - Prob. 34PCh. 31 - Prob. 35PCh. 31 - Prob. 36PCh. 31 - Prob. 37PCh. 31 - Prob. 38PCh. 31 - Prob. 39PCh. 31 - Prob. 40PCh. 31 - Prob. 41PCh. 31 - Prob. 42PCh. 31 - Prob. 43PCh. 31 - Prob. 44PCh. 31 - Prob. 45PCh. 31 - Prob. 46PCh. 31 - Prob. 47PCh. 31 - Prob. 48PCh. 31 - The rotating loop in an AC generator is a square...Ch. 31 - Prob. 50PCh. 31 - Prob. 51APCh. 31 - Prob. 52APCh. 31 - Prob. 53APCh. 31 - Prob. 54APCh. 31 - Prob. 55APCh. 31 - Prob. 56APCh. 31 - Prob. 57APCh. 31 - Prob. 58APCh. 31 - Prob. 59APCh. 31 - Prob. 60APCh. 31 - Prob. 61APCh. 31 - Prob. 62APCh. 31 - Prob. 63APCh. 31 - Prob. 64APCh. 31 - Prob. 65APCh. 31 - Prob. 66APCh. 31 - Prob. 67APCh. 31 - A conducting rod moves with a constant velocity in...Ch. 31 - Prob. 69APCh. 31 - Prob. 70APCh. 31 - Prob. 71APCh. 31 - Prob. 72APCh. 31 - Prob. 73APCh. 31 - Prob. 74APCh. 31 - Prob. 75APCh. 31 - Prob. 76APCh. 31 - Prob. 77APCh. 31 - Prob. 78APCh. 31 - Prob. 79CPCh. 31 - Prob. 80CPCh. 31 - Prob. 81CPCh. 31 - Prob. 82CPCh. 31 - Prob. 83CP
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- A dc motor with its rotor and field coils connected in serieshas an internal resistance of 3.2 Ω. When the motor is running at fullload on a 120 V line, the emf in the rotor is 105 V. What is the mechanical power developed by the motor?arrow_forwardSuppose a motor connected to a 117 V source draws 20.2 A when it first starts. (a) What is its resistance? (b) What current does it draw at its normal operating speed when it develops a 100 V back emf? (c) The motor in a toy car operates on 6.20 V, developing a 3.00 v back emf at normal speed. If it draws 2.80 A at normal speed, what current does it draw when starting? Aarrow_forwardThe generator of a car idling at 1.582E+3 rpm produces 15.3 V. What will the output be at a rotation speed of 2.886E+3 rpm, assuming nothing else changes? Answer in units of V.arrow_forward
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