A method of winding a generator or motor in which a shunt winding is
used for the field magnets and in which also a second winding of the
magnet is placed in series with the outer circuit. (See Winding,
Series–Winding, Shunt.)

The object of compound winding is to make a self-regulating dynamo and
this object is partly attained for a constant speed.

The characteristic curves of shunt and series winding are of opposite
natures. The first increases in electro-motive force for resistance in
the outer circuit, the latter decreases under the same conditions. If
the windings are so proportioned that these conditions for each one of
the two windings are equal and opposite, it is evident that the
characteristic may be a straight line. This, however, it will only be at
a single speed of rotation.