The variation of the rotor speed of the series-wound and shunt-wound DC traction motors, depending on the axle load, is shown by the curves depicted in Fig.
The analysis of the speed-torque characteristics of the DC series--wound and separately excited shunt-wound traction motors at the points A and B allows us to state that the rotor speed of a separately excited shunt-wound traction motor is hardly dependent on the load (speed variation [DELTA][n.
Wheel-to-Rail Adhesion of the Locomotives with Separately Excited Shunt-Wound and Series-Wound DC Traction Motors