Understanding Motor Controls
4th Edition
ISBN: 9781337798686
Author: Stephen L. Herman
Publisher: Delmar Cengage Learning
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Question
Chapter 37, Problem 10RQ
To determine
The size of the conductor used to supply the motors.
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Students have asked these similar questions
A 3 kVA motor operates from a 240 V
supply at 50 Hz and has a power
factor of 0.6. Determine the active
power
Select one:
1800 W
Non of the Answers
1900 W
2000 W
al
Three coils each having resistance of 29 N are connected in star across 422 V, 50 Hz supply. Then the total
power consumed is
O 211.77 W
O 3545.51 W
O 730.95 W
O 6140.83 W
The working current has a power of 100 kW and a power factor of 0.50. After a capacitor of 75 KVAR is installed, what does the
power factor become?
A 0.84
B 0.71
C 0.63
D 0.78
E 0.92
Chapter 37 Solutions
Understanding Motor Controls
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Similar questions
- Two transformers rated at 100 kVA each are connected in an open-delta connection. What is the total output power that can be supplied by this bank?arrow_forwardA 480-volt three-phase load is rated at 34.5 kVA. It is to be supplied with variable three-phase voltage. Because the load is continuous, the transformers ratings are to be increased by 1.25% of the rated load. Three variable autotransformers are used to supply this load. Refer to Table 4-2 and determine the standard size of each transformer that should be used to make this connection.arrow_forwardHow does the National Electrical Code specify that the high leg of a four-wire delta connection be marked?arrow_forward
- If dual-element time delay fuses are to be used as the short circuit protective device, what size fuses should be used to protect the circuit in question #12? Five 5 HP, three-phase motors with NEMA code B are connected to a 240-volt line. The conductors are copper with type THWN insulation. What size conductor should be used to supply all of these motors?arrow_forwardRefer to the transformer shown in Figure 5-13 to answer the following questions. What is the turns ratio of the winding between points B and E as compared to the winding between points D and E? Figure 5-13 Autotransformer practice problems.arrow_forwardA load impedance of 52 Ω is connected to the secondary winding of the transformer in question 3. How much current will flow in the secondary?arrow_forward
- A large motor has a full load current rating of 425 amperes. Current transformers with a ratio of 600:5 are used to reduce the current to the overload heaters. What should be the full load current rating of the overload heaters?arrow_forwardThe following data were obtained on a 50 kVA 2400/120 V transformer: Open circuit test, instruments on low voltage side: Waltmeter reading = 396 Watts Ammeter reading = 9.65 amperes Voltmeter reading = 120 Volts Short circuit test, instruments on high voltage side: Waltmeter reading = 810 Watts Ammeter reading = 20.8 amperes Voltmeter reading = 92 Volts Find the efficiency when rated kVA is delivered to a load having a power factor of 0.8 lagging.The following data were obtained on a 50 kVA 2400/120 V transformer : Open circuit test, instruments on low voltage side: Waltmeter reading = 396 Watts Ammeter reading = 9.65 amperes Voltmeter reading = 120 Volts Short circuit test, instruments on high voltage side: Waltmeter reading = 810 Watts Ammeter reading = 20.8 amperes Voltmeter reading = 92 Volts Find the efficiency when rated kVA is delivered to a load having a power factor of 0.8 lagging.arrow_forwardQuestion 4 A 228 V/ 111 V single-phase transformer has a core loss of 110 W and the no-load current is 0.7 A. The no load power factor is Not yet answered Marked out of O 0.99 1.00 O 1.42 P Flag question O 0.48 O 0.69 Question 5 A 2 kV / 229 V transformer has the secondary turns of 47. The number of Primary turns of a transformer is given by, Not yet answered 63.83 Marked out of 410.48 1.00 O 615.72 P Flag question O 5381.50 Question 6 For the given power transfer, a delta system is associated with larger line currents and a star system is associated with a larger line voltage. Not yet answered Select one: Marked out of O True 1.00 P Flag question O Falsearrow_forward
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