Self-starting, direct current motor with permanent magnets of varied magnetic strength
US4438362A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 19, 1982 |
| Grant date | Mar 20, 1984 |
| Priority date | — |
| Expiry date | Aug 19, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K29/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A permanent magnet, direct current motor is made self-starting by the use of permanent magnets with varying magnetization. The use of permanent magnets with varying magnetization results in a rotor position after motor de-energization such that the rotor is angularly offset from a cogged position. This type of motor is made by first, placing uniformly magnetized magnets in a rotor, placing the rotor in an air gap of a toroid on a fixture with a key that correctly positions the rotor, applying a satisfactory magnetic field for a suitable amount of time so that the desired varying magnetization is produced, and finally, assembling the rotor in operative association with the stator so that the at-rest position of the rotor is angularly offset in the direction of rotor rotation from a cogged position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.