| 摘要 |
<p>An improved apparatus and method for control of discharge lighting, such as HID (high intensity discharge) lighting, effects full-voltage start up of the lighting, and sustained operation of the lighting at a reduced voltage after a selected and variable start-up phase or interval. The apparatus includes an auto transformer (28 and 30) having a primary winding and a secondary winding. The primary winding is always in series with the load, but may be shorted to connect full line voltage from the line to the load. When the primary winding is not shorted, the secondary winding is connected to the load also, so that reduced voltage is provided to the load. A thermal analog device (36) simulates the warm up time constant of the HID lighting unit, so that the reduction in operating voltage to the HID lighting unit is effected only after this lighting unit has achieved a sufficiently high temperature to sustain operation at a reduced operating voltage.</p> |
