A study on loss-of-synchronism in stepping motors based on equilibrium rotor-angles

The present paper is concerned with a fundamental study on the phenomenon called Loss of Synchronism (LOS) in a stepping motor from the view-point of rotor-angles in equilibria. Conditions of the rotor are deliberated in terms of its angle, velocity, and acceleration, and a set of three conditions is proposed for determining the state of LOS. A simulation model is constructed in the Simulink environment for a hybrid five-phase stepping-motor that is driven by an industrial driver and is used for evaluating the derived conditions through extensive simulations. They show that the LOS state of the motor under ideal conditions can be detected correctly. The developed motor-driver model and the LOS algorithm are useful tools for simulating LOS and expected to pave a way to practical techniques for preventing and recovering from LOS.