D. C. electric motor
US5001375A · kind A · utility
Inventor
Key dates
| Filing date | Aug 9, 1989 |
| Grant date | Mar 19, 1991 |
| Priority date | — |
| Expiry date | Aug 9, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K29/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a d.c. motor, the stator may form the armature and has its windings inserted in slots in its cylindrical surface and the rotor may comprise a permanent magnet or be provided with d.c. windings. Switching means operate in synchronism with rotation of the rotor to connect a d.c. source to the armature windings so that a rotating field is produced in arrears of the rotor field to exert a repelling force on the rotor poles. Because the rotor and stator fields are in opposition, rather than in mutual assistance, less energy is needed to energize the windings to produce a given torque. Also the current in each winding is very low when commutation occurs and sparking avoided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.