Energy savings in Lighting Applications 
Stabilux Luminous Flux Regulator

IREM, Italy

Luminous Flux Regulator (LFR) is a centrally operated fully programmable light dimmer. The technology is based on servo-controlled autotransformer equipped with microprocessor based programming capabilities including remote control through telephone lines and personal computers. The LFR is used with gas discharge lamps like Fluorescent Lamps with Magnetic ballast, High Pressure (HPSV) and Low Pressure (LPSV / SOX) Sodium Vapor lamps, Mercury Vapor (HPMV) lamps, Metal Halide (MH) lamps and Compact Fluorescent Lamps (CFL/PL).   

 In addition to dimming the LFR primarily being a transformer, feeds stabilized power to the light installation thereby enhancing the lamp life. Stabilux is available in over 60 models to suit various plant loads and automated capabilities.

Operating Principle for Energy Savings with LFR

A gas discharge lamp once ignited and warmed up for about 10-15 minutes, can be subjected to controlled under powering by reducing the voltage. The reduction in voltage leads to substantial energy savings, upwards of 30 per cent with a limited reduction in light output. This under powering leads to power savings in relation to two situations:


LFR Operating Voltage (say 200 Volts) vs. Nominal Voltage (240 Volts) and also

Nominal Voltage (240Volts) vs. Grid Over Voltage (during lean hours, 258 Volts).

Commercial Applications of LFR

Dimming of large light installations can be achieved matching with the work place requirements in various ways as illustrated:

Street Lighting Stabilux is very successfully used all over Europe, and many parts for Asia for reducing the energy consumption of street / motorway / public lighting. Typically a street lighting / motorway lighting is required with full light output only till about 10 o'clock in the night. Afterwards the lights can be dimmed to the maximum possible extend, thereby saving power till next day morning. In addition to savings on account of difference between nominal voltage and operating voltage, additional 5-10% savings is extracted by Stabilux due to the shooting up of grid voltage over the nominal voltage. Dimming during lean hours is being considered as a safety measure (in Holland) as low illumination makes drivers more cautious. See the Attachment for an illustration of power savings with Stabilux.

Underground Facilities lighting Stabilux can be effectively used for lighting optimization in under ground facilities like hotel service areas, car parking, which typically have long lighting durations. For example, in car parking, the lamps can have maximum under powering through out the period of operation leading to very substantial savings. Lamp fixtures in such facilities can be regulated with EMR, EPT, PMR and PMT models. 

Facade Lighting
Stabilux can be deployed as an efficient energy saver for facade lighting of hotels, new generation building complexes, and monuments. After the peak evening hours these sites could have subdued lighting instead of a switch-off. This leads to power savings and reduced light pollution. The fully programmable PMR and PMT models are most suitable for this application.

Public and Township Street Lighting The full luminance of the HPSV lamps is ideally required between 1800 hours and 2200 hours. The lamps could be underpowered to an intermediate level from 2200-0000 hours. Thereafter upto 0600 hours maximum under powering can be effected. Stabilux can be programmed for a whole year for such operations to be compatible with daily requirements, summer and winter day lengths, and even requirements of special days when full luminance is required. The fully programmable PMR and PMT models provide these functionalities

General Plant Lighting, Stockyard, and Switchyard Lighting Illumination with HPSV and MH starts at 1800 hours in the evening. Once the ignition cycle is completed, the lamps can be under powered to the minimum voltage and still have enough luminance for functional requirements till 0600 hours next day. This application is easily facilitated by EMR and EPT versions, which are the economy models and also by the fully programmable PMR and PMT models.

Large Shop Floor Lighting  Stabilux PMT models can be attached to a Luminance Sensor for optimizing large shop floor lighting involving HPSV, HPMV and MH. The LFR will achieve a uniform illumination (constant lux) in the work place by taking full advantage of the daylight and gradually shifting the illumination to the lamps as night progresses.

The Stabilux LFR is manufactured by IREM of Italy who are in the voltage stabilization business for the last 40 years. World over IREM has installed over 
550,000 stabilizers of capacity upto 1000 kVA. Thousands of LFRs are working all over Europe, many parts of Asia and Africa since 1990 in tunnel, street, shop floor, airport and plant lighting applications. The esteemed clients of Stabilux include:

Alfa Romeo
Cairo Ringroad
CDG Airport Paris

Kuala Lumpur Motorway
Siemens, ST Microelectronics
Whirlpool...and many more

Perspective of Lamp Manufacturers  All leading lamp manufacturers (Philips, GE, Osram) endorse dimming as a new dimension to energy conservation without any adverse impact on lamp life and have evolved dimming guidelines for their various products.

©EnergyBay September 2002