Circuit for detecting burned-out lamp for a buoy lamp changer
US3964040A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 29, 1974 |
| Grant date | Jun 15, 1976 |
| Priority date | — |
| Expiry date | Oct 29, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B39/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A lamp out detection circuit is provided for a buoy lamp changer. The circuit includes an modified Hartley transistor oscillator which is tuned to operate at a preselected frequency. A typical lamp flasher applies power to the lamp and the lamp out circuit, simultaneously. If a normal lamp is in operation, a current pulse is inductively coupled to the oscillator in a manner suppressing sustained oscillation. Should the filament of an incircuit lamp fail or become electrically non conductive, the lack of inductive coupling to the oscillator would permit sustained oscillation which results in generation of a pulse signal. Time delay means are provided to ensure that the pulse signal is not intermittent. Further indexing through a time delay is provided to permit the lamp changer to rotate a new lamp into an operating position before further monitoring of faults occurs. Means are provided to prevent rotation of the turret after the last lamp has failed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.