Design and simulation of an asymmetric variable reluctance stepping millimotor

A pancake-shaped step motor, which has a geometry with an axial dimension that is much smaller than the radius, was designed and built using a combination of conventional and LIGA-based fabrication methods. Preliminary open loop dynamic testing indicated that the motor rotated normally as designed, but some abnormal phenomena were also observed at certain input frequencies. A simple model was developed to simulate the dynamic behavior of the rotor. The simulation results match the trend of abnormal behavior observed in the test. They indicate that a reliable open-loop operation is feasible for a wide range of operating frequencies.We would like to acknowledge the fabrication, testing, and other assistance of A. A. Jojola, V. E. Lucero, B. G. Carlen, T. R. Christenson, W. D. Bonivert, M. A. Bankert, J. T. Hachman, D. R. Boehme, A. M. Morales and J. M. Hruby. Sandia National Laboratories is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Dept. of Energy under Contract DE-AC04-94AL85000.