Lamp ballast with near unity power factor and low harmonic content
US4538094A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 12, 1983 |
| Grant date | Aug 27, 1985 |
| Priority date | — |
| Expiry date | Aug 12, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A magnetic ballast circuit for a fluorescent lamp providing improved power factor, reduced harmonic content and increased efficiency. A ballast circuit with three inductances connected to a junction, preferably with the first and second inductances comprising a tapped autotransformer, with the third inductance connected between a line terminal and the tap, with the first inductance connected in series with a capacitance to the other line terminal, and with the second inductance connected to the load. The first inductance may be provided totally as part of the autotransformer, or may be supplemented with a second inductance in series. In an alternative embodiment, separate inductances may be utilized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.