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Ballast Technical Information

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Basics of... Electronic Ballasts

Purpose of Electronic Ballasts

Ballasts start lamps and provide the proper voltage to establish an arc between the lamp's two electrodes. There are two types of starting methods.

Instant Start: the least expensive method, starting lamps without delay (< 0.1 seconds) or flicker

  • Best suited for applications with limited switches (the number of on/off cycles ) each day
  • Ballasts provide a starting voltage sufficiently high enough to start a discharge through the lamps without the need for heating lamp electrodes
  • Elimination of electrode heating maximizes energy savings – typically saving 2 watts per lamp compared to rapid start ballasts
  • Lamps operated by instant start ballasts typically operate 10,000 to 15,000 switch cycles before failure

Program Rapid Start: allows more starts per lamp, therefore maximizing lamp life

  • Designed to provide maximum lamp life in frequent lamp starting applications such as areas where occupancy sensor controls are used
  • Start lamps quickly (1.0 – 1.5 seconds) without flicker
  • Lamps operated by programmed start ballasts typically operate 50,000 switch cycles before failure

Considerations for Choosing the Right Ballast

Determining Light Output

  • Ballasts regulate the electric current flowing through the lamp to stabilize light output
  • Ballast Factor (BF) is a measurement of light output
  • Multiplying the BF times the rated lamp lumens will determine actual light output of a given system operated on commercial ballasts.

Rated lamp lumens x Ballast Factor (BF) = Light

Ballast Factors Low: .71 to .78 BF Normal: ∼.88 BF High: 1.15 – 1.25 BF

  • A lower than normal BF can save energy but reduces lamplight output to below normal
  • A higher than normal BF is used when maximum light from the lamp being used is desired

Determining Lamp Energy Usage

  • The amount of energy the lamp is going to use changes depending on the type of ballast being used
  • System wattage is determined by lamp and ballast combo
Feature Comparison
FeatureStandard ElectCentiumOptanium
Voltage120 or 277120/277 Intellivolt120/277 Intellivolt
EfficiencyBetterGoodBest
Safety Type CC RatingNoNoYes
Cold Start-20°
Anti-Striation*NoNoYes

*Striation is the spiraling or swirling of fluorescent lamps at initial turn on

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