Transformers Objectives Part 05
81 . A tap changer is used on a transformer for adjustments in secondary voltage
82 . Over currents in a transformer affects insulation life, temperature rise and mechanical stress
83 . In a transformer the tapings are usually provided on high voltage side
84 . A current transformer used the instruments like ammeter, Wattmeter and Watt hour meter
85 . Voltage transformer of 0.1 class of accuracy is used
86 . Three transformer each of the single phase type sets will be costly
87 . Commutator is not fitting on the transformer
88 . The reactance of a transformer depends on the leakage flux
89 . If the frequency of the supply voltage is double eddy current loss will increase
90 . No load current in a transformer as a percentage of full load current is 1% to 3%
91 . In a transformer maximum voltage regulation occurs when the power factor of the load is lagging
92 . The regulation of a good transformer should be near 1%
93 . In a step up transformer the f2/f1 has value one
94 . In a transformer minimum voltage regulation occurs when the power factor of the load is leading
95 . Scott connections are used to three phase to three phase and three phase to two phase transformation
96 . In Scott connections the neutral point divides the teaser winding in the ratio 1:2
97 . In a large capacity transformer 5% of the turns at the ends of high voltage winding are provided with extra insulation to provide protection due to surges occurring during switching operations
98 . The permittivity of Bakelite is approximately 4.4
99 . The permittivity of transformer oil is about 2.2
100 . Buchholz relay is used in transformer protection
