Input frequency control device for surface acoustic wave motor
US4743788A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1986 |
| Grant date | May 10, 1988 |
| Priority date | — |
| Expiry date | Nov 12, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02N2/163
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A surface acoustic wave motor utilizing ultrasonic vibration has an elastic member and piezoelectric elements for vibrating the elastic member. The motor is provided with a monitor voltage detecting circuit for detecting a monitor voltage generated by the vibration, from a portion of the piezoelectric elements not receiving the input voltage, and a frequency control circuit for controlling the input power supply frequency in such a manner that the monitor voltage assumes a predetermined value lower than a maximum monitor voltage obtained at the resonance frequency of the stator consisting of the elastic member and piezoelectric elements, in a frequency range higher than the resonance frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.