Occasionally I come across someone asking about putting those 90w T17's on a rapid-start circuit. A few years ago, I even did some experiments with F96/HO and VHO ballasts. I had determined they weren't compatable because the T17 lamp voltage is too low (about 60v if I recall). Recently, I acquired some more VHO ballasts and T17 lamps...this time I tried a
GE F48T12/VHO ballast. The lamp was still overdriven because the T17 still has a lower operating voltage than a F48 VHO but I then realized there was an even BIGGER problem....
Ok, initially, when I did the experiment, the ballasts were 525v OCV so lamps started quickly. When I tried using the GE ballast....which despite the label, has ONLY 280 OCV. the lamps glowed dim with bluish ends. I then removed a wire from each end of one lamp and manually PREHEATD it and presto....they both came on! So, I realized the filaments have high resistance. I did measurements and sure enough, the 4v filament current was too low (wrote it down and lost it). This is the same behavior as, say, a 15 or 20w lamp on a regular 30 or 40w RS ballast. That's why PH exclusive lamps, such as 14-20w require about 9v filament current, aka trigger-start.
From all of this, I would have to say that in order to run a T17 "Rapid Start", they will have to be in a "Trigger Start" situation. Naturally, my first thought, since the T17's have similar voltage to regular 20w lamps is to get about 5 or 6 20w trigger start ballasts and carefully connect them in parallel. That means the wire pairs will have to be right polarity or the filament voltages will become shorted.
In the future, I may try something like this.