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10. The hysteresis loss in the core of a transformer can be reduced by A. increasing the frequency of the aliemating current, B. using a solid iron core. C. using grain-oriented-steel D, reducing the connected load. 11. In Fig. 1(b) in the text, the phasor I, It is the resultant of the A. exciting and the magnetizing current. B. active and the reactive secondary current. C. primary and the exciting current. D. magnetizing and the core-loss current. 12. The resistance of a transformer winding is 0.5 ohm at 25 C. After a period of continuous operation, the measured resistance is 0.6 ohm and the temperature of the winding is A. 30.8 C. B. 20.8 C. C. 46.9 C. D. 76.9 C. 13. A core-form three-phase delta-delta transformer can provide some service with one phase damaged if the damaged phase is A. disconnected and short-circuited. B. grounded. C. open-circuited D. short-circuited. 14. In a 15.000-kva delta-delta bank of three single-phase transformers, one transformer has developeda fault. The remaining transformers, if reconnected in open delta, will be able to carry safely A. 10.000 kva. B. 8655 kva. C. 12.990 kva. D. 15.000 kva. 15. A two-phase load of 5 kva is to be supplied from a three-phase line by the aid of Scott-connected transformers. If the voltage across each three-phase winding- is 220 volts, the two-phase load current will be A. 2.20 amp. B. 11.36 amp. C. 13.12 amp. h one of the follow ing diagrams shows delta delta connections of three single phase transformers of subtractive polarity on a three phase system H, N3 в, x, A C. x, a x, D. 2. A reactor is sometimes used with an autotransformer to A. incrcabe the full-load currem B. provide iscreased internal impedance C. limia shorn-circuit curment. D, decrcase the voltage ratio.

Answer 1

8655 kv