Variable reluctance (VR) motors attract much attention in motor and automation industries because they are reliable and inexpensive. With advances in power electronics and high-speed processors, the performance of VR motors has been enhanced greatly. In electronically commutated VR motors the windings of different phases are constantly switched on and off; the turn-on and turn-off delays of the winding currents significantly affect the motor torque ripple in high-speed applications. In this paper a mathematical model is presented to describe how the delays influence the output torque of the VR motor. The validity of the model is demonstrated by both computer simulation and laboratory experiments.