Electrical Transformers and Rotating Machines
4th Edition
ISBN: 9781305494817
Author: Stephen L. Herman
Publisher: Cengage Learning
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Textbook Question
Chapter 10, Problem 6RQ
A 10 kVA transformer has a primary voltage rating of 240 volts and a secondary voltage rating of 480 volts. The transformer is connected to a circuit protected by a 100 ampere circuit breaker. The secondary is protected by a 25-ampere fuse. Does the primary require separate overcurrent protection?
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Chapter 10 Solutions
Electrical Transformers and Rotating Machines
Ch. 10 - Prob. 1RQCh. 10 - What size overcurrent device should be used to...Ch. 10 - Prob. 3RQCh. 10 - The secondary of the transformer in question #3...Ch. 10 - A 10 kVA transformer has a primary voltage of 208...Ch. 10 - A 10 kVA transformer has a primary voltage rating...Ch. 10 - What size conductor should be used to connect the...
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- 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_forwardWhat is a special hazard encountered in large industrial transformers used in unit substations?arrow_forwardA 10 kVA transformer has a primary voltage of 208 volts and a secondary voltage of 120 volts. What size circuit breaker should be used to protect the primary winding?arrow_forward
- What hazard is involved in water-cooled transformers?arrow_forwardWhat is one special problem with dry-type transformers used in unit substations?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_forward
- A long-shunt compound-wound generator gives 240 volts at F.L. output of 100A. The resistances of various windings of the machine are : armature (including brush contact) 0.1 Q, series field 0.02 Q, inter pole field 0.025 2, shunt field (including regulating 0.2 resistance) 100 2. The iron loss at F.L. is 1000 W; windage and friction losses total 500 W. Calculate F.L. efficiency of the machine.arrow_forwardIs the transformer in question 1 a step-up or step-down transformer?arrow_forwardThere is an ambient temperature of 65°C with a temperature rating of the conductor as 75°C. What is the ambient temperature correction factor based on 86°F?arrow_forward
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