Commutatorless electrical motor having sub magnetic poles
US4417186A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 12, 1982 |
| Grant date | Nov 22, 1983 |
| Priority date | — |
| Expiry date | Jan 12, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K29/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A commutatorless electrical motor comprises a cylindrical magnetic rotor having main magnetic poles where N and S poles are alternately arranged in the circumferential direction, and an axis of N and S poles of each magnet extends radially, and a sub magnetic poles at one end of the cylindrical rotor. The sub magnetic poles are arranged such that N and S poles of each magnetized area extends axially. The magnetized area providing each sub magnetic pole has an arcuate extent of .pi./2 or less in an electrical angle. Each of the magnetized area providing each sub magnetic pole makes a given change in the magnetic flux density distribution in the vicinity of rotational position detecting elements so that the rotational position of the rotor can be accurately detected. As a result, current switching circuit for changing over armature currents will be controlled by the accurate information from the detecting elements, and thus each armature winding will be energized in a desirable manner, reducing undesirable torque ripple.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.