Tridonic 22158561 OMBX 35/55 B154K – Limited Stock

SOX lamps (Sodium Oxide) are a type of Low-Pressure Sodium (LPS) vapor lamp. Historically common for street lighting across the UK, they are renowned for their extreme energy efficiency and signature amber-yellow glow.

Key Characteristics

Monochromatic Light: SOX lamps emit almost all of their light at a single wavelength (589 nm). Because the human eye is highly sensitive to this wavelength, they produce very bright light per watt (high luminous efficacy).
Zero Colour Rendering: Because the light is purely yellow, colour distinction is non-existent. Objects appear only in shades of black and amber.
Warm-up Time: They require about 10 minutes to reach full brightness. When initially switched on, they glow a faint pinkish-red because the internal neon gas ignites before the sodium vaporises.
High Efficiency: They are among the most efficient artificial light sources ever created, historically achieving up to 200 lumens per watt.

SOX ballasts are specialised electrical control gears designed to start and safely operate Low-Pressure Sodium (LPS) or SOX/SOX-E lamps. These lamps (which emit a distinctive bright, monochromatic yellow light) have been historically used for street and security lighting.

How SOX Ballasts Work

Current and Voltage Regulation: Unlike standard fluorescent lights, LPS lamps need to run on a constant, tightly regulated current. SOX ballasts are predominantly electromagnetic leak transformers that provide a high striking voltage to start the arc, then limit the current as the lamp heats up.

Ignitor Requirement: Because SOX lamps require significant initial voltage to strike (typically hundreds of volts), many SOX ballasts must be paired with an external ignitor or rely on an integrated ignitor design to get the lamp to turn on.
Capacitor Usage: A Power Factor Correction (PFC) capacitor is almost always wired into the circuit alongside the ballast to correct the inductive load and balance the system.

SOX vs. SOX-E Ballasts

Standard SOX: These were the traditional ballasts, designed for older, standard-wattage LPS lamps.
SOX-E: These were introduced as energy-saving variants. While SOX-E lamps use less power and run at different currents, they generally operate at about 60% of the full SOX current.
Compatibility: It is not recommended to run a standard SOX lamp on a SOX-E driver, or vice versa, as this causes the lamp to run improperly (often flickering or producing incorrect power outputs) and can heavily degrade the lifespan of expensive replacement lamps.

Tridonic are a Zumtobel Group company, founded in 1956 in Dornbirn, Austria. For more than 60 years, they have been a driving force in the development of professional lighting solutions.

Today, Tridonic is a world-leading provider of lighting technology for professional applications, including office buildings, and retail outlets, hotels and restaurants, the education industry and outdoor lighting sectors.

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