China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

Rapid start ballasts supply a controlled low voltage (filament voltage) which heats the lamp cathodes sufficiently for the starting voltage to initiate an arc. If the filament voltage is low, the lamps may not start.Rapid start ballast apply a low filament voltage to preheat the cathodes. Simultaneously, a starting voltage (lower than that used in instant start) is also applied to strike the arc. When the cathodes are hot enough, the lamp will strike. The filament voltage continues to be applied throughout the operation of the lamp. Rapid start ballasts appear to have a slight turn on delay compared to instant start. They will typically not be able to start lamps reliably under 50 degrees F.

The filament voltages for the most typically encountered rapid start ballasts are:

F30T12/RS – 3.5 to 4 volts
800ma – 3.5 to 4.3 volts
F40T12/RS – 3.5 to 4 volts
1500ma – 3.5 to 4.3 volts
Cathode Cut-Out (Hybrid) Rapid Start Ballasts

To perform the tests outlined above on (2) lamp hybrid ballasts, one lamp must be in place while the other sockets are tested. Remove only one lamp at a time.

Electronic Ballasts for Rapid Start Lamps

Because of the special operating characteristics of many electronic ballasts, such as high-frequency operation, parallel circuitry and instant starting, field testing can be difficult and procedures varied. Eliminate other possible causes and replace the ballast if necessary.