161. A transformer has negative voltage regulation when its load power factor is
a. zero
b. leading
c. unity
d. lagging

162. The essential condition for parallel operation of two single phase transformer is that they should have the same
a. voltage ratio
b. Kva rating
c. polarity
d. percentage impedance

163. When the impedance triangles of two transformers operating in parallel are not identical in shape and size, the two transformers will
a. get heated unequally
b. share the load unequally
c. run with different power factors
d. none of the above

164. A scott connected transformer cannot be paralleled with a
a. v – v transformer
b. y – delta transformer
c. delta – delta transformer
d. y – transformer

165. In the parallel operation of transformer which statement is false
a. transformers transformation ratios same
b. transformers voltage ratings same
c. transformers kVA ratings equal
d. none of the above

166. A step up transformers increases
a. current
b. power
c. frequency
d. voltage

167. Open circuit test on a transformer is done to determine
a. efficiency
b. cu loss
c. core loss
d. none of the above