Why is open ckt test conducted on lv side?
in the open circuit test, the high voltage winding is open
circuited and the measurements are made on the low winding side
i.e, the open circuit test is performed on the L.V side. This is
because if the measurements are made on HV side then voltage
applied must be large and the current would be unsuitably small,
for which the high voltage sources may not be readily available and
at the same time the instrument ranges required should be very
high, Also the result obtained may not be accurate.
NOTE: iron loss will be same, if measured from either of the
winding.
in short circuit test. the low voltage winding is short
circuited and the measurements are made on the high voltage winding
side i,e,. the sort circuit test is performed on H.V side. This is
because if the test is performed on the L.V side, the current will
be suitably large for which the instruments used should be of very
high ranges. moreover instruments of such high ranges and the
auto-transformer capable of handling such high currents may not be
readily available.