Technical Bulletin

5
Lighting Fixture operations (101)
This section will cover three different aspects of lighting fixtures: Occupancy Sensor, Electronic Ballasts, and
Fluorescent Ballasts
Occupancy Sensors
Sensors are a simple relay device, similar to a light switch. When motion is detected a relay closes completing
the current path to the ballast which then “strikes” the lamp.
Electronic Ballasts
Ballast selection and operation varies, always consult a ballast manufacturer for operation and best practices.
 Instant-start electronic ballasts are the most popular type of electronic ballast today because they
provide maximum energy savings and they start lamps without delay or flashing. Since they do not
provide lamp electrode heating, instant-start ballasts generally consume less energy than comparable
rapid-start, program rapid-start or programmed-start ballasts. As a result, they usually provide the most
energy efficient solution. Instant-start ballasts use 1.5 to 2 watts less energy per lamp than rapid-start.
They also have the least amount of output leads, making for easy installation.
Instant-start electronic ballasts provide a high initial voltage (typically 600V for F32T8 lamps) to “strike”
the lamp. This high voltage initiates discharge between the unheated electrodes of the lamp. However,
the cold electrodes of lamps operated by an instant-start ballast may deteriorate more quickly than the
warmed electrodes of lamps operated by a rapid-start, program rapid-start or programmed-start
ballasts. Lamps operated by instant-start ballasts will typically withstand 10-15 thousand switch cycles.
Instant-start ballasts are typically wired in parallel. This means that if one lamp fails, the other lamps in
the circuit will remain lit.
 Rapid-start ballasts have a separate set of windings which provide a low voltage (approx. 3.5 volts) to
the electrodes for one second prior to lamp ignition. A starting voltage somewhat lower than that of an
instant-start ballast (typically 450-550V for F32T8 lamps) is applied, striking an electrical arc inside the
lamp. Most rapid-start electronic ballasts continue to heat the electrode even after the lamp has
started, which results in a power loss of 1.5 to 2 watts per lamp. Lamps operated by a rapid-start
electronic ballast will typically withstand 15-20 thousand switch cycles. Rapid-start ballasts are typically
wired in series. This means that if one lamp fails, all other lamps in the circuit will extinguish.
 Programmed-start electronic ballasts provide maximum lamp life in frequent starting conditions
(>50,000 starts). Programmed-start ballasts like the Mark 5TM, Mark 7TM, Mark 10TM, and
OptaniumTM programmed-start family of products use a custom integrated circuit which monitors lamp
and ballast conditions to ensure optimal system lighting performance. Programmed-start ballasts
precisely heat the lamp cathodes to approximately 700°C prior to lamp ignition, thus the lamps are
delayed upon startup. This puts the least amount of stress on the lamp electrodes, resulting in
maximum lamp life regardless of the number of lamp starts. Programmed-start ballasts are typically
wired in series, so if one lamp fails….
Fluorescent Lamps
These fluorescent tubes are gas-discharge lamps that use electricity to excite mercury vapor. The excited
atoms produce short-wave ultraviolet light causing a phosphor to fluoresce, producing visible light. Fluorescent
lamps require a ballast to regulate the flow of power through the lamp. A fluorescent lamp converts electrical
power into useful light more efficiently than an incandescent lamp. Lower energy cost typically offsets the
higher initial cost of the lamp.