RAPID START BALLAST
A rapid start (RS) fluorescent ballast heats the lamp filaments (cathodes) with a low voltage before striking the arc to turn the lamp on, providing a longer lamp life and better performance in frequently cycled applications compared to instant start ballasts. This continuous preheating means they have a slight turn-on delay, may not start reliably in very cold temperatures (below 50'F), but are ideal for applications like garages or kitchens where lights are turned on and off frequently.
How it works
Constant filament heating: A low voltage is continuously applied to the filaments, keeping them hot throughout the lamp's operation.
Starting the arc: When the light switch is turned on, the ballast applies a starting voltage to strike the arc across the gas inside the tube.
Faster ignition: Because the filaments are already hot, the lamp ignites quickly, though there may be a slight delay compared to an instant start.
Longevity: This preheating process is gentler on the cathodes than the high-voltage "blast" of an instant start ballast, which helps preserve lamp life and reduces the blackening that occurs with frequent on/off cycles.
Key characteristics
Turn-on delay: A slight delay of about a second is normal.
Performance in cold: Do not reliably start lamps below 50?F.
Dimming: Compatible with dimming circuits, which is impossible with an instant-start ballast.
Best for: Areas with frequent on/off cycles, such as garages, basements, or kitchens.