Abstract

A lighting control system which comprises an AC mains power point, power distribution means coupled to the AC mains, a dimmer assembly comprising one or a plurality of co-located dimmer circuits each coupled to the distribution means to receive AC power therefrom, and each comprising an output port developing an AC power signal of frequency corresponding to the AC mains, each said dimmer circuit comprising a current path between the distribution means and the output port, a switching means located in the current path so as to controllably interrupt passage of current, switch driving means supplying a control signal to the switching means to cause it to interrupt the current path a multiplicity of times within each AC half cycle, and filtering means in the current path between the switching means and the output port arranged to smooth the current therethrough, the filtering means being arranged to attenuate current components at the frequency of operation of the switching means, and not substantially to attenuate current components at the frequency of the mains, the switch driving means being controllable to vary the duty factor of operation of the switching means, so as to provide at the output port a power signal at the mains frequency with an RMS amplitude related to the duty factor of the switching means; dimmer control means connected via a connection means to the switch driving means of each dimmer circuit to vary the duty factor thereof in accordance with a desired power output thereof; a power cable connected to each output port to enable one or many luminaire units to be supplied with power from a respective dimmer unit.