Abstract
A number of devices are available which can be incorporated at the electrical distribution board in a building to reduce the voltage and hence the power consumed by an existing fluorescent lighting installation. Certain of these are generally known as 'energy limiters'. Voltage reductions not only reduce power consumption but also cause a drop in light output and changes to other lamp operating conditions, depending on lamp type, ballast circuit and luminaire. This paper describes a detailed investigation of five voltage (RMS) reducing devices: four based on auto-transformers and one on a reverse phase electronic dimmer. Nineteen lamp and ballast circuit combinations and a range of luminaire types were studied. Data are given on the effects of voltage reduction on lamp light output, power consumption, lamp starting and stability, power factor, induced harmonic distortion and system efficiency. Potential problems are highlighted and economic factors are discussed. It is recommended that these devices are only considered for retrofit in areas where a decrease in illuminance is acceptable. A new lighting installation should be designed to operate at full rated supply voltage using modern energy-efficient lamps and luminaires to obtain the most effective lighting solution.
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