Selection for Street Light Luminar-(PART-5)


Type of Ballasts

  • Discharge lamps (fluorescent, HID) and solid state lamps cannot be connected directly to the mains for its functioning. It required control gear for starting the Lamp.
  • This gear has mainly two functions ignition of the lamp and control of the functioning by supplying the right lamp voltage and limiting the electric current.
  • Control gear conventionally consists of three parts (1) Ballast (coil), (2) Capacitor and (3) Igniter.
  • Commonly the control gear is called ballast.
  • Ballast is classified under following categories. (1) Electromagnetic and (2) electronic.
  • Electronics Ballast: Electromagnetic ballast has electromagnetic ballast, an igniter (not for HPM-lamps) and a capacitor.
  • The ballast lifetime depends on service hours. Normally, magnetic ballasts last as long as the luminaries if they are placed inside the luminaries (and thus are protected against rain).
  • The lifetime of igniters associated with magnetic ballasts does not depend on hours in service but on the number of times that the lamps are switched on.
  • Electronics Ballast: An electronic ballast is mostly one unit that provides both ignition and good functioning (by supplying the right lamp voltage and limiting the electric current) of the lamp.
  • For electronic ballasts, lifetimes of 40.000 to 60.000 hours (10 to 15 years) are considered.
  • The lifetime of electronic ballasts decreases strongly if the working temperature in reality exceeds the indicated working temperature.
  • Electronic ballast includes an ignition device and does not have a separate igniter.

 Power Consumption in Ballasts:

  •  Electronics Ballast: Normally the Fluorescent lights are using electronic ballast (called solid state ballast) which consume above 12 watts power.
  • Magnetic Ballast: the stating modes are available in Programmed stat, instant stat, and rapid start Lamp flicker index is 0.04 to 0.07, Dimming is not available for this ballast.
  • Hybrid Ballast: the stating mode is rapid stat, Lamp flicker index is 0.04-0.07. Dimming is not available for this ballast.
  • Instant start Ballast: supply a high initial voltage (over 400V) to start the lamp. High voltage is required to initiate the Discharge between unheated electrodes.  
  • Rapid Start Ballast: supply 200-300V to start the lamp, which can heating the electrodes to approximately 1470˚F(800˚C).
  • It starts the lamp with brief delay but without flashing. And for the Fluorescent lamp, warm up time is also minimum 5 minutes.

 Replacement of Laminar:

  •  HSPV produce a yellowish light, have a long life, are very energy-efficient, and have good lumen maintenance (maintain light output for a long period of time), but have poor color rendering properties.
  • MH lamps are the most frequently used alternative to HPSV in new installations. They are also quite efficient and provide much better color rendering. However, these lamps tend to have a shorter lamp life (< 10000 hours) and poor lumen maintenance over the life of the lamp.
  • Mercury lamp replaced to incandescent lamp:
  • This is popular conversion of laminar. The initial cost of MV Lamp is high and it requires ballast, but MV Lamp have high efficacy and long life make it considerably more attractive than the incandescent lamp.
  • The blue-white color of the clear lamp is generally acceptable, and the arc tube size provides a light source that is small enough to permit good light control.
  • A phosphor-coated outer bulb, featuring both higher output and more pleasing color rendition, is also available. However, the light source is the size of the outer bulb, presenting a problem in light control.
  • The metal halide lamp is a type of mercury lamp in which the arc tube contains, in addition to mercury, certain metal halides which improve both the efficacy and the color rendition without the use of a phosphor-coated bulb. The light source size is that of the arc tube, permitting good light control in the same fixture used for clear mercury lamps.
  • MV lamps are the least efficient of the HID types and have poor lumen maintenance
  • High pressure sodium (HPS) lamp replaced tomercury :
  • The high pressure sodium (HPS) lamp is presently replacing the mercury lamp. It has golden-white color light output.
  • HPS lamps are normally operated with special ballasts that provide the necessary high voltage to start the lamp. However, lamps are available that can be operated from certain types of mercury lamp ballasts, but with poorer lumen maintenance and shorter life. There are also HPS lamps available that provide improved color rendition or almost instant restart after a power interruption; either feature results in a reduction in rated life.
  • LED replaced toHigh pressure sodium (HPS) lamp :
  • LED lights use approximately 60% less electricity than HPS lights

Savings by Use of More Efficient Lamps (Bureau of Energy Efficiency)

Existing LampReplace byEnergy Savings
GLS (Incandescent)Compact Fluorescent Lamp (CFL)35 to 60 %
High Pressure Mercury Vapor (HPMV)40 to 50 %
Metal Halide65 %
High Pressure Sodium Vapor (HPSV)65 to 75%
Tungsten HalogenHigh Pressure Mercury Vapor (HPMV)50 to 60 %
Metal Halide40 to 70 %
High Pressure Sodium Vapor (HPSV)40 to 80 %
High Pressure Mercury Vapor(HPMV)Metal Halide35 %
High Pressure Sodium Vapor (HPSV)35 to 60 %
Low Pressure Sodium Vapor (HPSV)60 %
Metal HalideHigh Pressure Sodium Vapor (HPSV)30 %
Low Pressure Sodium Vapor (HPSV)40 %
High Pressure Sodium Vapor(HPSV)Low Pressure Sodium Vapor (HPSV)40 %



Variation in Light Output and Power Consumption (BEE, India)

Type of Lamp10% lower voltage10% Higher voltage
Light Out PutPower Out PutLight Out PutPower Out Put
Fluorescent lampsDecreased 9%Decreased 15%Increased 9%Increased 15%
HPMV lampsDecreased 20%Decreased 16%Increased 20%Increased 17%
Mercury Blended lampsDecreased 24%Decreased 20%Increased 30%Increased 20%
Metal Halide lampsDecreased 30%Decreased 20%Increased 30%Increased 20%
HPSV lampsDecreased 28%Decreased 20%Increased 30%Increased 26%
LPSV lampsDecreased 4%Decreased 8%Increased 2%Increased 3%


  • Indian Renewable Energy Development Agency
  • USAID-India.