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Lighting Reference Guide – HID Lamp Ballasts

10 HID Lamp Ballasts

a. Ballasts General

Like fluorescent lamps, HID lamps are electric discharge lamps. A ballast is required to provide proper starting and operating voltage and current in order to initiate and sustain the arc.

b. Probe Start Ballasts

The standard core and coil HID ballast or probe start ballast consists of a series of electrical coils on a core of steel laminations. The coils are impregnated with a varnish to provide electrical insulation, reduce noise and dissipate heat. Some ballasts for interior use are housed in metal cans and potted with insulating materials.

c. Pulse Start Ballasts

  • Pulse start HID Ballasts incorporate a different starting technique which reduces ballast losses and increases lamp performance.
  • Pulse start retrofits can be a good measure for existing metal halide installations in schools, industrial and commercial projects.
  • A 320 W metal halide pulse start system can replace a 400 W system.
  • The pulse start lamp gives less lamp lumen depreciation, better colour consistency over lamp life, and faster hot restrike.

d. Electronic HID Ballasts

Designed primarily for the low wattage Ceramic Metal Halide lamps, the electronic HID ballasts are gradually expanding to higher lamp wattages.


  • Significantly smaller size and lower weight than core and coil systems.
  • More efficient, up to 20% savings over conventional ballasts.
  • Square wave output increases lamp life.
  • Automatic end–of–life detection; shuts lamp down instead of trying to restart.

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