Method and circuit for improving HID lamp starting
US5339005A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 1993 |
| Grant date | Aug 16, 1994 |
| Priority date | — |
| Expiry date | Oct 6, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/05
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In one aspect of the present invention a capacitor is placed in series with the ballast and the lamp. The capacitor lowers the impedance during lamp starting and is shorted out when final arc conditions of the lamp are reached. Method and device for improvement of lumen maintenance of high intensity discharge lamps through minimizing the wall blackening during lamp starting is disclosed. Reducing the electrode material sputtering during the thermionic arc phase of the lamp starting process was achieved by decreasing the cathode fall voltage. The cathode fall voltage in these lamps was decreased by increasing the current flowing through during the starting phase. The increase of starting current was achieved by increasing the open circuit voltage or by decreasing ballast impedance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.