Q. Explain Shunt-field control process?

Shunt-field control, armature-resistance control offers a constant-torque drive because both flux and, to a first approximation, allowable armature current remain constant as speed varies. The shunted-armature method is a variation of this control scheme. This is illustrated in Figure (a) as applied to a series motor, and in Figure (b) as applied to a shunt motor. Resistors R₁ and R₂ act as voltage dividers applying a reduced voltage to the armature. They offer greater flexibility in their adjustments to provide the desired performance.