The speed control of Shunt continuous racing engines has peculiar characteristics. The reduction of the armature current causes the reduction of the internally developed torque, so that the developed torque is similar to the resistant torque (load torque), however at a higher speed. This decrease causes the developed torque to also decrease. And finally, once again rab lighting the torque equals the load torque at a speed higher than the initial speed.
As usually the armature is made with thicker wire and has fewer turns than the shunt winding of the stator, the armature consumes current larger than the stator. Rotation motion and torque are results of the interaction of the magnetic field in the stator with the magnetic field in the armature created by the armature current. In a shunt DC motor, the field circuit is fed directly through the armature terminals of the electric motor. The terminal (output) characteristic of a shunt motor is a graph that relates the output variables to each other. For the motor, the output variables are the torque on the shaft and the speed.