Armature Resistance in DC Generators
Armature resistance “Ra” is the resistance offered by the armature circuit. It comprises,
a. Armature Winding Resistance
Armature Winding resistance is the ohmic resistance of the copper winding wires.
b. Resistance of Brushes
A brush is used to provide electrical contact between the stationary contacts and moving parts like commutator or slip rings. Brushes are mainly made of carbon material which is high resistance brushes compared to copper brushes.
Usually, the armature resistance of a motor is less than 1 Ω.