| 摘要 |
A grid is suspended some distance below a permanent ceiling. The grid has plural grid openings. Each grid opening is covered by a regular ceiling panel or by a special light-weight lighting panel. Both the ceiling panels and the lighting panels are readily installable and movable, without requiring the making or breaking of hard-wire electrical connections. Each one of the lighting panels is powered by way of an individual flexible cord-and-plug means. This cord-and-plug means is plugged into a male receptacle on the lighting panel and into a female receptacle on a special power supply mounted on the permanent ceiling above this one ceiling panel. This special power supply has several such female receptacle means and can accommodate several ceiling panels. To power all the lighting panels of a complete ceiling, several of the special power supplies are used. To provide protection against fire initiation hazard, the power available from each individual female receptacle on each special power supply is limited in accordance with the specifications for Class-3 electrical circuits under the National Electrical Code. To provide for light weight in the lighting panels, the frequency of the voltage provided from the special power supplies is 30 kHz, thereby permitting the use of very light-of-weight components in the lighting panels.
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