FLUORESCENT BALLASTS TYPES BASIC INFORMATION AND TUTORIALS

Preheat.

Preheat ballasts are connected in a simple series circuit. They are easily identified because they have a “starter.” One type of starter is automatic and looks like a small roll of Lifesavers with two “buttons” on one end.

Another type of starter is a manual “ON–OFF” switch that has a momentary “make” position just beyond the “ON” position. When you push the switch on and hold it there for a few seconds, the lamp filaments glow. When the switch is released, the start contacts open, an arc is initiated within the lamp, and the lamp lights up.

Preheat lamps have two pins on each end. Preheat lamps and ballasts are not used for dimming applications.

Rapid Start.

Probably the most common type used today. Rapid start ballasts/lamps do not require a starter. The lamps start in less than 1 second. For reliable starting, ballast manufacturers recommend that there be a grounded metal surface within ½ in. (12.7 mm) of the lamp and running the full length of the lamp, that the ballast be grounded, and that the supply circuit originates from a grounded system.

T5 rapid start lamps do not require a grounded surface for reliable starting. Rapid start lamps have two pins on each end. Rapid start lamps can be dimmed using a special dimming ballast.

Instant Start.

Instant start lamps do not require a starter. These ballasts provide a high-voltage “kick” to start the lamp instantly. They require special fluorescent lamps that do not require preheating of the lamp filaments.

Because instant start fluorescent lamps are started by brute force, they have a shorter life (as much as 40% less) than rapid start lamps when older style magnetic ballasts are used. With electronic ballasts, satisfactory lamp life can be expected.

Instant start lamps have one pin on each end. Instant start ballasts/lamps cannot be used for dimming applications.

Dimming Ballasts.

Special dimming ballasts and dimmers are needed for controlling the light output of fluorescent lamps. Rapid start lamps are used. Incandescent lamp dimmers cannot be used to control fluorescent lamps. An exception to this is that dimmers marked “Incandescent Only” can be used to dim compact fluorescent lamps.