ohm meter
test lamp
voltage drop
Wheatstone bridge method
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