Track lighting systems are commonplace in many applications, including commercial (e.g. retail store), residential, and museum applications. Track systems offer flexibility such that lighting fixture arrangements may be reconfigured to meet the changing lighting requirements of a space without the need for skilled tradesmen or additional specialized equipment to adjust existing fixtures or to install additional fixtures. Lighting fixtures within track lighting systems may also be readily changed or reconfigured in order to keep pace with changing styles and technological advances.
High-intensity discharge (“HID”) lamps are popular because they are able to convert a greater amount of the energy they consume into visible light, as opposed to heat. They are much more energy efficient than traditional incandescent light sources. Light-emitting diode (“LED”) and fluorescent lamps have also found popularity due to their low power consumption and long life. HID, LED, and fluorescent lamps, however, require power supplies that condition the power provided to the lamp (e.g. higher voltage to strike an electrical arc in an HID lamp, regulated constant current or voltage for LED lamps, etc.). Such power supplies and the enclosures that typically contain them may occupy a relatively large amount of space. This may be problematic in a track lighting system because space is very often in short supply within the track, as many lighting installations call for the use of a large number of fixtures to achieve the required light levels or the desired lighting effects.
One way to provide power to HID, LED, or fluorescent track fixtures is by means of power supply units physically located below the track (see, e.g., U.S. Pat. No. 3,489,981, D413,176, D436,678, and D552,780). There are real cost and performance constraints that require that the power supplies be located in general proximity to the light sources, but not so close that they can be affected by the heat produced by the light sources. Additionally, there are electrical and building code regulations that require power supplies and other electrical components to be located so they are readily accessible for replacement or inspection. These constraints and regulations have, for the most part, defined the arrangement and location of the power supply within the lighting system in relationship to the track and the light source. As such, the power supplies are typically built into each fixture in an isolated enclosure, thus creating an additional and fully visible element as an integral part of the light fixture and the lighting system itself. Such an arrangement and the resulting system, however, may not be aesthetically pleasing. Accordingly, there is a need for a power delivery system for HID, LED or fluorescent light sources where a power supply may be substantially contained within a track, and in some instances, the power supply should be kept in relative proximity to the light source, but providing a less cluttered and more aesthetically pleasing appearance.