91. For successful parallel operation of two single phase transformers, the most essential condition is that their
- percentage impedances are equal
- polarities are properly connected
- turn ratios are exactly equal
- kVA ratings are equal
92. Two transformers when operating in parallel will share the load depending upon which of the following?
- magnetizing current
- leakage reactance
- per unit impedance
- efficiency
93. Auto transformer can do the following
- step up voltage
- step down voltage
- both (1) and (2)
- none of these
94. In an auto transformer, power is transferred through
- conduction process only
- induction process only
- both conduction and induction process
- mutual coupling
95. It is advisable to use auto transformer if the transformation ratio is
- greater than 1
- near to 1
- 0.25
- 0.5
96. The saving in copper achieved by converting ordinary two winding transformer into an auto transformer is governed by the
- secondary load
- size of the core
- voltage transformation ratio
- none of the above
97. Constant current transformer is of ________ type.
- core
- shell
- core or shell
- none of these
98. High leakage reactance transformers are of
- small volt-ampere rating
- high volt-ampere rating
- high voltage rating
- low voltage rating
99. A tap changer is used on a transformer for adjusting the _______ voltage.
- primary
- secondary
- both primary and secondary
- none of the above
100. In a constant voltage transformer, the output voltage remains constant due to
- capacitor
- input inductor
- saturation
- tapped windings