6 NM PRECISION PEL
The PEL-6 Sector Light has been designed to operate day+night, and to provide a 24-hour signal from a single source. There is no need for separate day marks or more than one tower.
The PEL-6 carries a 24 V DC 250 Watt halogen lamp and is capable of 6 NM daylight range (at a horizontal subtense of 3.5 degrees).
The actual range depends on atmospheric transmissivity and background lighting.
Designed and built to withstand the harsh marine environments where they are usually installed, they do not require any special protection, and are fully sealed to prevent ingress of moisture and corrosive salts. Marine-grade bronze and stainless steel are used for the enclosure to ensure long life – many PEL Lights around the world have been in service for more than 20 years and are still working reliably.
For operation at night the intensity needs to be decreased to between 1% and 20% of day intensity. The exact value depends on the level of background lighting by day and by night. If there are bright lights in the background at night, less reduction is required. PEL Sector Lights use two methods to achieve a satisfactory reduction without changing to a different-sized lamp: Lamp Voltage Reduction and Night Filter insertion.
Lamp Voltage Reduction is achieved by changing the mark-space ration in the pulsed power to the lamp. Night voltage can be reduced in 5 steps to give as little as 10% of day (full) intensity.
Night Filter Insertion involves inserting a neutral-density filter into the beam at night. This reduces the intensity to 5% – 25% without changing the colour of the sectors or the location and sharpness of their boundaries.
The PEL-6 can use a combination of the two to achieve a night intensity as low as 0.5% of day. The transmissivity of the Night Filter is fixed at manufacture, but Lamp Voltage Reduction can be adjusted on site after installation.