In DC machines, the field poles are on the stator called yoke. Armature windings and commutator are on rotor.Cross section view of 2 pole DC machine is given.Brushes press on to commutator surface for collecting the power from DC generator or for feeding dc power to the armature of a dc motor. DC machines are of three types: series, shunt ans compound. DC series machine has field winding in series with armature circuit, dc shunt machine has field winding across the armature circuit whereas a dc compound machine has two field windings, one field winding across the armature and second field winding in series with the armature.
DC machines are also fitted with interpoles. Large dc machines have also compensating windings embedded in pole faces embedded in the pole faces of main poles.
DC machines possess versatile operating characterstics . DC motor is easily adaptable for speed control and electric braking.
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