Principles and Applications of Electrical Engineering
6th Edition
ISBN: 9780073529592
Author: Giorgio Rizzoni Professor of Mechanical Engineering, James A. Kearns Dr.
Publisher: McGraw-Hill Education
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Chapter 7, Problem 7.71HP
A residential four-wire system supplies power at 240 V rms to the following single-phase appliances:On the first phase, there are ten 60-W bulbs. On the second phase, there is a 1-kW vacuum cleaner with apower factor of 0.9. On the third phase, there are ten23-W compact fluorescent lamps with a power factor of 0.61. Find:
a. The current in the netural wire.
b. The real, reactive, and apparent power for eachphase.
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Suppose the circuit shown represents a residential distribution circuit in which the impedances of the service conductors are negligible and Vg1=Vg2=120 0° V (rms). The three loads in the circuit are L1 (a new refrigerator, a coffee maker, and a microwave oven); L2 (2 incandescent lamps, a humidifier, and a ceiling fan); and L3 (a clothes washer and a clothes dryer). Assume that all of these appliances are in operation at the same time. The service conductors are protected with 20 A circuit breakers. Will the service to this residence beinterrupted? Why or why not?
A residential four-wire system supplies power at 220 V rms to the following single-phase appliances: On the first phase, there are ten 60-W bulbs. On the second phase, there is a 1-kW vacuum cleaner with a power factor of 0.9. On the third phase, there are ten 23-W compact fluorescent lamps with power factor of 0.61. Find a. The current in the neutral wire. b. The real, reactive, and apparent power for each phase.
A residential four-wire system supplies power at220 V rms to the following single-phase appliances:On the first phase, there are ten 75-W bulbs. On thesecond phase, there is a 750-W vacuum cleaner with apower factor of 0.87. On the third phase, there are ten40-W fluorescent lamps with power factor of 0.64.Finda. The current in the netural wire.b. The real, reactive, and apparent power for eachphase.
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Principles and Applications of Electrical Engineering
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