Hey guys, an old grandmother like figure to me that used to keep saltwater tanks and tropical parrots at a local shop I visit every so often told me that she has a 24 inch durotest power twist fluorescent from back in the 80s or so that she found and I can get the next time I visit her! She now lives about 3 hrs away. She's willing to ship it but I would rather pick it up in person to ensure that it stays in good shape especially since it has a special origin… Her old shop I used to go to with my dad when I was a child. I plan to visit her within the next month or two. I remember seeing them in her shop  in the earlier 90s for the birds, I am not sure if it is a vita-lite or not, but she said that it says preheat on it! So should I definitely try to purchase/have to build preheat fixture for it or could it be run in a rapid start etc., it is a 24 inch T12 power groove. I was looking to build a 24 inch preheat fixture or to try to buy one off of Amazon new old stock Lithonia Preheat and see what I get as discussed in the other post! If it is not maybe I can convert it to preheat with you guys help,  but if it turns out to be rapid start or electronic but rated for a 20 watt bulb, would it take care of this bulb for me or could it harm it because bulb says preheat right on it?  Thanks guys!

Programed Start electronic - ok

Instant Start - no

Rapid Start magnetic - idk if it will appreciate constant heating of the cathodes. Lets wait for more answers

A rapidstart fluorescent lamp, have a lower starting voltage than a similar lamp that says "Preheat".
Starting a rapidstart fluorescent lamp on a preheat ballast, may cause the lamp to start directly from the mains, before the starter contacts closes in 230-240V countries, much like the old Tungsram 40W T12 lamps.

In the US that is no problem. IF the instant start ballast is rated for the lamp no problem either if the socket are wired properly, but frequent switching off and on  will reduce life expectancy on that lamp and even those intended for instant start service.  Our F96T12 lamps rate only 12,000 hours at either 3 or 6 hours a start ( I don't remember) but they are on 12 or more hours a day. They last past 20,000 hours normally.

I think old school preheat it will be!  Programmed start sounds neat, but I really want to see if amazon truly has Lithonia S120PH, that truly is the fixture I would love to have, with old style starter :-). It won't be right to run a special old bulb in anything different the more I think about it :-). Thanks guys, OHH, if I order the Lithonia S120PH and it really IS NOS preheat I will follow up so you guys can buy them too, they are $8-$12 each!  I'm excited to see if that's actually what I get or if they stick in a new electronic ballasted fixture! Also I will get photos of the power twist running once I get it!  Hopefully she is correct and it really is a workig power twist.  She is very wise for her age so I trust her!

I think that a rapidstart lamp is a fluorescent lamp that have an emitter that require a higher temperature in order to bring the electrodes to the thermionic emission mode, so it requires a continuous electrodes heating and so a rapidstart ballast.
Operating a rapidstart lamp in a preheat ballast may results in a cold cathodes operation (As preheat don't heats the electrodes during operation but only before the starting, thats why the rapidstart have the highest losses of any other type of ballast) and a shorter life (We had a NOS GE FC8T9/D RS on a preheat circular fixture in my mother kitchen, and it was dead within a year only, when the glow starter in the fixture, stuck.

 I had old Preheat Westinghoue lamp lasted 20 years on Rapid start. being switch all the time like 5 mins to being left on overnite. Rapid start is best for lamp anyways. As it dont sputter the emission. On eash startups on Preheat. Preheat/switch start decent if you let the me burn about 3 hours per start. but the key for preheat is to heat the cathode. at predetermin time like 5 to 7 seconds to give it a good warm up
 this minimize the emission sputturing. Instant start ok if your going to burn lamp by leaving the lights on for the day. not turn them off until the end of your days works. electronic program start mixed feeling
 as ballast may fail before the Life one vintage lamps. It all boils down to what your application is for lighting.


 
 

Now that's a 24 inch 20 watt bulb. There is no "rapid start" for these lamps, but Trigger start is similar, and I expect it heats the cathode / filament at the right voltage for the 20 watt lamps in preheat service.  I got some 30,000 hours out of Chroma 50 20 watt lamps in 24/7 service in a dual lamp trigger start, as that is ALL there is in that style anymore other than for the 24 inch F17T8 which is instant start solid state ballast powered. 

Powell

I had a couple of those F20 VitaLite Power Twist lamps ... they lasted for years on my fishtank light (which was rapid-start)