a) With the transformer de-energized, eight complete cycles of operation (a cycle of operation goes from one end of the tapping range to the other, and back again).
b) With the transformer de-energized, and with the auxiliary voltage reduced to 85% of its rated value, one complete cycle of operation.
c) With the transformer energized at rated voltage and frequency at no load, one complete cycle of operation.
d) With one winding short-circuited and, as far as practicable, rated current in the tapped winding, 10 cycles of tap-change operations across the range of ± two steps on each side from where a coarse or reversing changeover selector operates, or otherwise from the middle tapping (the tap changer will pass 20 times through the changeover position).