Electric drive system and method
US6127791A · kind A · utility
Inventor
Key dates
| Filing date | Sep 2, 1997 |
| Grant date | Oct 3, 2000 |
| Priority date | — |
| Expiry date | Sep 2, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/905
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
An integrated transmission is effectively achieved within a series-excited motor by varying the number of winding turns in the field coil in relation to the speed-torque demand on the motor. At low motor speed, all of the field winding is engaged to produce the maximum available electromagnetic field, thereby increasing the motor's available torque and efficiency. When there is a high torque demand at high speed, only a portion of the field winding is engaged so that a reduced electromagnetic field is produced, thereby allowing a higher current in the motor, thereby allowing a higher torque to be produced. Thus the series motor with integrated transmission will have the same speed-torque characteristics as a system with a series motor and a conventional transmission. The integrated transmission can be implemented with relatively inexpensive relays and, if desired, by adding additional winding turns in the series field. The advantage of the integrated transmission is that it is less costly than and eliminates the weight of a separate transmission, which are important in applications like electric vehicles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.