## Electrical Machines In a DC machine

emf in armature conductors and at the terminals is alternating.
current and emf in armature are unidirectional
current and emf in armature are alternating.
current and emf at the terminals are alternating.

## Electrical Machines The results of a slip test for determining direct axis (Xd) and quadrature axis (Xq) reactances of a star connected salient pole alternator are given below Phase values: Vmax = 108 V ; Vmin = 96 V Imax = 12 A ; Imin = 10 A Hence the two reactances will be

Xd = 9Ω and Xq = 9.6Ω
Xd = 9.6Ω and Xq = 9Ω
Xd = 8Ω and Xq = 10.8Ω
Xd = 10.8Ω and Xq = 8Ω

## Electrical Machines What does the use the of height flux density value in transformer design lead to?

Reduced copper loss.
Reduced iron loss.
Increase in weight/KVA.
Decrease in weight/KVA.

120 / PN Hz.
120P / N Hz.
PN / 2 Hz.
120N / P Hz.

3.1 Ω
1.8 9 Ω
2 .1 Ω
1.79 Ω

## Electrical Machines Open circuit test on transformer gives

eddy current loss
hysteresis loss
both 1and 2
copper loss