steady d.c.

steady a.c.

pulsating a.c.

pulsating d.c

no effect takes place

current flow is stopped

The direction of current flow is reversed

the magnitude of current flow is decreased

rotating magnetic field past stationary coils

relative motion between the field and the armature coils

converting electrical energy into mechanical energy

rotating the coils around a magnetic field

long shunt

short shunt

differential compound

cumulative compound

MNA (magnetic neutral axis)

GNA (geometric neutral axis)

perpendicular to MNA

perpendicular to GNA