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Luminous efficacy of a typical HPSV lamp is in between
40 - 70 lm/watt.
70 - 120 lm/watt.
120 - 200 lm/watt.
10 - 40 lm/watt
70 - 120 lm/watt.
The luminous efficacy of a High-Pressure Sodium Vapor (HPSV) lamp typically ranges between 70 and 120 lumens per watt. This high efficiency makes it a preferred choice for street lighting and large outdoor area illumination.
The luminous efficacy of a High-Pressure Sodium Vapor (HPSV) lamp typically ranges between 70 and 120 lumens per watt. This high efficiency makes it a preferred choice for street lighting and large outdoor area illumination.
╬╖=P╬жтАЛ тАФ where ╬╖ is efficacy (lm/W), ╬ж is total luminous flux (lm), and P is power input (W).
The HPSV lamp operates via an electric discharge through ionized sodium vapor mixed with xenon gas. The xenon acts as a starter gas, while the sodium is vaporized by the heat generated from the arc discharge, producing a characteristic golden-white light. The high pressure within the discharge tube results in collision broadening of the spectral lines, improving both efficacy and color rendering compared to low-pressure sodium lamps.
HPSV lamps offer a long service life of up to 24,000 hours.
They require a ballast to limit the current and an ignitor to provide the high-voltage pulse for starting.
The color rendering index (CRI) of HPSV lamps is generally low (approx. 20-30), which is a characteristic trade-off for their high efficacy.
High luminous efficacy
Long lamp life
Excellent reliability in outdoor environments
Poor color rendering
Requires significant warm-up time to reach full brightness
Sensitive to supply voltage fluctuations
Street and roadway lighting
Industrial high-bay lighting
Large area floodlighting
Standard HPSV lamp power ratings usually vary from 50W to 1000W.
Low-pressure sodium (LPS) lamps have higher efficacy (up to 200 lm/W) but offer poor monochromatic yellow light.
B is correct тАФ The luminous efficacy of a typical HPSV lamp is in the range of 70-120 lm/watt.
Always distinguish between HPSV (High Pressure) and LPS (Low Pressure) lamps; LPS lamps are more efficient but have poor color rendering, whereas HPSV provides a balance.