Special alternator assembly with an inherent ballast impedance characteristic for lighting systems
US5808450A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 15, 1996 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Aug 15, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K21/14
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An engine-driven alternator assembly includes an output winding having an internal impedance characteristic similar to a separate stationary ballast for high intensity discharge lamps. The output winding is direct connected to lamps in a mobile light tower application having four HID lamps. The alternator assembly includes four separate alternator units each having an output winding wound to establish the inherent internal impedance to provide a ballast source for the connected lamp. Each alternator unit has its rotor mounted on a common shaft connected to the shaft of the engine. Each alternator unit establishes an open circuit voltage to strike an arc across the HID lamp and then a sustaining voltage to maintain current flow as well as limiting the current to the lamp. The alternator unit has a high frequency output, preferably within 200 to 600 hertz. The alternator unit is a permanent magnet alternator, a switched reluctance alternator, an induction alternator, or a wound synchronous alternator. A full wave bridge may be connected across the alternator output to supply the limited direct current to the lamp, and the engine may be controlled to create the voltage change.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.