Document Type


Date of Award


Degree Name

Master of Science in Electrical Engineering - (M.S.)


Electrical Engineering

First Advisor

William N. Carr

Second Advisor

Roy H. Cornely

Third Advisor

Durgamadhab Misra


The objective of this research was to model the performance and optimize geometries for two types of magnetic micromotors: yoke-type (YTMM) and yokeless (YSMM). The two selected micromotor types matched the designs that have been described in the recent research literature. Modeling was accomplished using MAXWELL, an advanced 2-D and 3-D simulator. The micromotors with nickel and nickel-iron magnetic thin films for the rotor and stator were simulated for torque performance. Three-phase power supplies with overlapping and non-overlapping phases were used. Rotor diameter dimensions were varied from 285 to 600µm, and the rotor-stator air gap was varied from 3 to 5µm. The number of rotor poles was varied from 4 to 10. The maximum torque obtained from the YTMM was in the range 76nNt?m to 360nNt?m, depending on geometry and permeability. The maximum torque that could be obtained from the YSMM was15.5nNt?m, which was considerably less than that for the YTMM for comparable permeability, dimensions, and rotor/stator pole combinations. The torque advantage of the YTMM is due to the decreased reluctance in the magnetic path. Simulation indicated that the motor torque increased with ampere turns, rotor/stator pole thickness, relative permeability of the material, and the number of rotor/stator poles. The torque was found to decrease as the inverse air gap separation. This work is significant because it is the first detailed study of magnetic micromotors by computer simulation.



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