Modeling dynamic end effects in rotary armature of rotary-linear induction motor

The performance of twin-armature rotary-linear induction motor is presented in this paper. The stator consists of a rotary armature and linear armature placed aside one another. Both armatures have a common rotor which consists of solid iron cylinder covered with a thin copper layer. The rotor can move rotary, linearly or with helical motion. The linear motion generates dynamic end effect on both linear and rotary armature. Modeling such an effect in rotary armature is a significant challenge as it requires a solution considering motion with two degrees of mechanical freedom. The approach used to address linear motion on rotary armature is based on the combination of transient time-domain finite element model and frequency-domain slip frequency technique. The results obtained from finite element modeling are then verified by test carried out on experimental model of the motor what validates the proposed method.