Transformer Questions

Parallel Operation of transformer and auto transformer

1)Two Transformers operating in parallel will share the load depending upon their
a) ratings.
b) leakage reactance.
c) efficiency.
d)per unit impedance.

Ans :(d)

2)In an auto-tranformer, power is transferred,through
a) conduction process only.
b) induction process only.
c)both conduction and induction processes.
d) mutual coupling.

3)Two Transformers,with equal rating and negligible excitation current, connected in parallel,share the load in the ratio of their kVA ratings only,if their pu impedances (based on their own kVA) are
a)equal.
b)in the inverse ratio of their ratings.
c)in the direct ratio of their ratings.
d)pure reactive.

Ans : (a)

4)Scott connections are used for
a)single - phase to three - phase transformation.
b)three - phase to single - phase transformation.
c)three - phase to two - phase transformation.
d)three - phase to six - phase transformation.

Ans :(c)

5)In Scott connection, if the turns ratio of main transformer is K,then the teaser transformer has turns ratio of
a)2K/√3
b)√3K/2
c)K/√3
d)K/2

Ans : (b)