Illumination system utilizing H.I.D. (high intensity discharge) lamps, and having a subordinate lamp automatically activated to establish immediate illumination when the H.I.D. lamp circuit is turned on, i.e., without awaiting the usual warm-up period, and to maintain illumination during periods of voltage dip (which normally extinguishes H.I.D. lamps) in the circuit supplying them, as well as during subsequent recovery and restarting the H.I.D. lamps after extinguishment as a result of voltage dip or other outage condition.
This invention is for an improved high intensity discharge lighting fixture. The lighting fixture includes a ballast which is adapted to be connected to a source of electric power. A first high intensity discharge socket is electrically connected to the ballast. A second high intensity discharge socket is electrically connected in parallel to the first high intensity socket and the second high intensity discharge socket is connected to the ballast in parallel with the first high intensity discharge socket.
An instant light lamp combining a miniature arc tube and a standby filament in a sealed vitreous envelope is operated by a high frequency power supply combined with a filament control circuit. The power supply comprises transforming means including voltage sensing means having an output proportional to the drop across the arc tube. The control circuit comprises an electronic switch for energizing the filament and a comparator circuit which has an output gating on the switch when the sensing means output is either above a high limit or below a low limit.
A second lamp is connected to power terminals upon each alternate switching off of a first lamp so that, upon each alternate switching on of the first lamp, the second lamp is illuminated. A magnetic latching relay switches the second lamp into and out of the circuit. The relay is powered by the discharge of one of two capacitors. One capacitor powers a set circuit of the latching relay, and another capacitor powers a reset circuit. Only one of the capacitors is charged at any one time. While power is applied to the power terminals to illuminate the first light, one capacitor is held discharged while the other capacitor is charged in preparation for powering the latching relay. The discharge of the charged capacitor through the latching relay is controlled electronically by a triac having a control terminal which is brought to control voltage by a fourth capacitor after a third capacitor has been discharged over a predetermined short time.
A light source includes a high pressure discharge lamp and incandescent filaments which provide illumination during the warm-up and hot restart periods associated with the discharge lamp. A current regulator, which provides dc power to the discharge lamp, draws sufficient current through one filament to energize the filament only during discharge lamp warm-up. A second filament provides illumination during the period after the occurrence of a momentary power failure or power transient which is required by the discharge lamp to cool down to its maximum starting temperature. A bimetal switch permits current flow through the second filament when the discharge lamp is above the maximum starting temperature. An electronic switch permits current flow through the second filament when a current sensing resistor senses a lack of current through the discharge lamp.
An automatic relamping system that provides for operation of a single one of multiple illumination lamps with automatic illumination of a next lamp upon failure of an illuminated lamp. A drive circuit is provided for the multiple lamps including an oscillator and means for connecting the multiple lamps in a parallel circuit with the drive circuit. The connections between lamps include direct conductive conductors so that upon starting of any one of the multiple lamps and ignition thereof, the other lamps are inhibited from ignition due to the reduced "on" voltage, in comparison to the "starting" voltage, of the ignited lamp.
