shape of the two winding coils

commutator connection

method of placing the coils in the slots

power output

fibre

bamboo

milinex

all the three stated above

open, closed, semi-open

open, closed, semi-enclosed

round, square, triangular

none of these

increase the insulation of the windings

make the windings vibrationless

provide an additional insulation layer on the windings

all the three stated above

for short-circuit test only

for open-circuit test only

For 'earth' fault test only

for all the three above stated tests