Effect of the non-linearity of demagnetization curves on the torque of hybrid stepping motors with permanent magnets in slots

The recent achievements in electronic control as well as the higher performance of advanced permanent magnets have brought about a change in the general strategy for design and development of new types of small electrical machines. A special application of permanent magnets (PM) is represented by hybrid stepping motors (HSM). The latter are a sort of combination of variable reluctance‐motors and permanent magnet‐motors. The influence of various PM inserts into the magnetic circuits of electromechanical converters on field and force distribution has been already investigated by the authors (1996). Promising results for HSM have been reported, especially when rare‐earth PMs are used. The main…

The Shaping of Flux Density at the Air Gap of Small DC Motors with Different Permanent-Magnet Poles

Design, operation and reliability of permanent-magnet DC micromotors are highly dependent of the magnet employed, i.e. of its demagnetization curve, type of magnetization (either radial or tangential), size and position within the micromotor as well as of its shape.

Flux density at the airgap of small DC motors with different permanent-magnet poles

Different Permanent-Magnet Structures and their Influence on the Torque of Small DC Motors

The design of permanent-magnet DC micromotors implies solving a number of problems. A few of them belong to all DC micromotors, i.e. size and number of rotor slots, width of air gap, external stator and internal rotor diameter, ratio of length to rotor diameter etc.1. One problem, certainly not the lowest in importance is, however, specific2, i.e. the choice of the most convenient permanent magnet for prescribed specifications of the micromotor. To date the progress in the production of permanent magnets has made it possible to work out different structures of motors and, for each structure, the most suitable permanent magnet for specified applications. Rare-earth permanent magnets and, in …