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High Consistency and High Accuracy Permanent Magnet Stepper Motor

IP.com Disclosure Number: IPCOM000060795D
Original Publication Date: 1986-May-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Krimm, DL: AUTHOR [+3]

Abstract

A permanent magnet stepper motor is fine tuned to achieve a very small amount of two phases on step error and/or very consistent torque. A permanent magnet stepping motor 1 has a rotor magnet 2 cooperating with a front stator can 3 and a rear stator can 4. Windings 5 are disposed within the front stator can 3, and windings 6 are disposed within the rear stator can 4. The front stator can 3 is supported on a mounting plate 7, and the rear stator can 4 is mounted on a rear bearing plate 8. At the completion of assembly, the rotor magnet 2 is rotated at a constant speed. The back emf of the winding 5 is sensed over conductors 9 and 10, while the back emf of the winding 6 is sensed over conductors 11 and 12. As the motor 1 is rotated, the back emf from the two windings 5 and 6 is continuously monitored.

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High Consistency and High Accuracy Permanent Magnet Stepper Motor

A permanent magnet stepper motor is fine tuned to achieve a very small amount of two phases on step error and/or very consistent torque. A permanent magnet stepping motor 1 has a rotor magnet 2 cooperating with a front stator can 3 and a rear stator can 4. Windings 5 are disposed within the front stator can 3, and windings 6 are disposed within the rear stator can 4. The front stator can 3 is supported on a mounting plate 7, and the rear stator can 4 is mounted on a rear bearing plate 8. At the completion of assembly, the rotor magnet 2 is rotated at a constant speed. The back emf of the winding 5 is sensed over conductors 9 and 10, while the back emf of the winding 6 is sensed over conductors 11 and 12. As the motor 1 is rotated, the back emf from the two windings 5 and 6 is continuously monitored. One of the two windings 5 and 6 will produce a higher back emf than the other to indicate that one end of the magnet 2 is stronger than the other. To demagnetize the end of the rotor magnet 2 having the stronger magnetism, a small magnetic probe 13 (shown double size) would be inserted through an opening 14 in the mounting plate 7 if the end of the magnet 2 adjacent the front stator can 3 is stronger, as evidenced by the back emf on the conductors 9 and 10 being higher than the back emf on the conductors 11 and
12. If the back emf on the conductors 11 and 12 is stronger, then the probe 13 is inserted th...