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High Cogging Torque Stepping Motor

IP.com Disclosure Number: IPCOM000045049D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Pawletko, JP: AUTHOR

Abstract

There are many applications where energy conservation is very important, as in portable devices. The device described in this article has this property and consists of a four-pole stator 10 and a three-pole rotor 12 with a permanent magnet ring 14 acting as the main flux source and a spacer, between the South and North sides 12S and 12N, respectively, of the rotor 12. The North and South poles of the rotor are displaced 60 degrees from each other, as shown in Fig. 1.

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High Cogging Torque Stepping Motor

There are many applications where energy conservation is very important, as in portable devices. The device described in this article has this property and consists of a four-pole stator 10 and a three-pole rotor 12 with a permanent magnet ring 14 acting as the main flux source and a spacer, between the South and North sides 12S and 12N, respectively, of the rotor 12. The North and South poles of the rotor are displaced 60 degrees from each other, as shown in Fig. 1.

When the rotor 12 is in an equilibrium position, poles 1 and 3 are magnetically aligned. Poles 2 and 4 shunt the magnet flux, such that equal and opposing force vectors are developed. The flux and pole distribution will result in a stiff detent characteristic.

To advance the rotor 12 counterclockwise, transistor switch 16 is closed momentarily. Pole 2 will develop South polarity, and pole 4 the opposite or North polarity. This condition will attract the North part of rotor 12N and also repel the South part 12S so that double action or force takes place. The same phenomenon occurs at pole 4. At the end of the pulse, the North pole of rotor 12 is in line with stator pole 2. Fig. 3 gives the step sequence and stator pole polarities.

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