Electric Machines Mega Quiz 11

(a) size of air gap

(b) shape of the pole shoe

(c) clearance between tips of the adjacent pole shoes

(d) all of the above

(a) silicon steel

(b) copper

(c) non-ferrous material

(d) cast-iron

(a) brushes should be of proper grade and size

(b) brushes should smoothly run in the holders

(c) smooth, concentric commutator properly undercut

(d) all of the above

(a) identified by the scarring of the commutator segment to which open circuited coil is connected

(b) indicated by a spark completely around the commutator

(c) both (a) and (b)

(d) none of the above

(a) to increase the generated voltage

(b) to reduce sparking

(c) to save the copper because of shorter end connections

(d) due to (b) and (c) above