I just came across this on eBay. This is supposedly a preheat ballast, but the wiring diagram does not show a starter. How does this ballast start the lamps? This is something I've never seen before.

-Nelson

I see two option:
- The starter is integrated into the ballast case. Likely electronic, but i've read somewhere, then simple glowbottles were integrated too...
- It is electronic ballast and they want to stress, then it "preheat" electrodes before the ignition, even if "standard" term for such ballast in US is "programmed start"

I have an old one of these from an old desk light set.  The one I have has an internal glowbottle that happens to be shorted.  I just cut the starter leads off and use an external starter with it.

Hmmm, seems like a cheap way to design a ballast, but I might actually buy a few for my lights that don't have a good place to mount starters.

How well will these work in the cold? I'm looking for ballasts that will start down to 0 deg. F. My other preheat chokes work fine at these temperatures.

Preheaters usually work fine, actually when first reading about RS (here the virtually all magnetic ballast type are preheater) i was surprised, then something as sensitive on the temperature or humidity is accepted... And these troubles are not known here...

My 2 x F30T8 bug zapper has this type ballast. They work great and start up quickly.
Good idea on the starter, icefoglights. I have always wondered how long the starter would last, especially in an often neglected bug zapper!

RS actually works just fine.  You have to remember that the vast majority of fluorescent lighting is installed in climate controlled spaces.  And when it's not, it still works pretty well.  I saw outdoor RS installations in Louisiana that would light when it was too muggy to stand.  As far as cold goes, I've seen them start down below freezing, just at reduced light output until the lamps can warm up.

I've actually had problems with rapid start ballasts and climate. I help a friend of mine on occasion with lights that are in a damp basement. When the basement is cool and damp, his 40W rapid start lights will not start. Sometimes you can flick the switch a few times and get some to light, but its spotty. The ballasts are quality Advance brand and the tubes are Mainlighters.

I will have to do a little testing while its cold and see what I can do with rapid start.

I just tried a one lamp 40W rapid start fixture with a 40W lamp out in my barn last night. The barn and fixture was about 15 deg. F. The lamp would only start if I touched the lamp in just the right place! Even that was sporadic. I also made sure the ballast and fixture (with reflector) were properly grounded. So I guess I will pick up more preheat ballasts when funds permit! I don't really have any extra money to spend on lighting right now.

@nogden: When I need a light to start in any temp and don't have the correct preheat ballast, I go with instant start. Always works no matter what and they are cheap on ebay. Instant start is hard on bulbs but it gets the job done where rapid start will not. I wish it was easier to get nos preheat at a good price...

I think calling every type of electronic ballasts that preheats the electrodes before ignition "Programmed Start" is wrong, since the majority of the low cost ballasts that do this, relays on a PTC, and aren't programmed at all.
"Programmed Start" is more correct term for those electrodes ballasts that its electrodes preheating mechnism is done by a smart interface in which the the electrodes preheating time, current, voltage and resistance programmed into.
Electronic ballasts that preheats the electrodes by means of a PTC, haven't any programmed preheating information, and have less reliable preheating (Lamps that operates with them usually have only 6,000-10,000 hours life, similar to instant start ballasts), and a more correct term for them is simply "Preheat electronic ballasts" or "Electronic preheaters".

@nogden: 1-lamp RS F40 ballasts are much more picky about starting in cool/cold than the 2-lamp version (especially if they are low power factor 1-lamp) Some of the better 2-lamp F40 high power factor ones can start (at least fairly reliably) down in 'teen temps and to a lesser extent to single digit temps (F)...if the fixture is grounded.
Once it gets below zero your choice is pretty much limited to electronic (unless you go with HighOutput)

I can't say if humidity affects things...where i live its dry/very-low humidity most of the time

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A couple weeks ago i took a few 8' lights out to the patio for a 'freeze test' LOL temp was -2f
#1 2x F96T12 Slimline (60w ES lamps) ... very dim glow in one lamp, but wouldn't start (as expected)
#2 2x F96T12 Slimline (75w lamps) ... very dim glow in one lamp, but wouldn't start
#2 2x F96T12 High Output (110w lamps) ... Fired right up (but dim at first)

The normal slimlines sorta surprised me..i would have expected it to fire up but say dim :?

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maybe next below zero night i'll try some F40T12's on the following:
2xF40T12-RS/LPF
2xF40T12-RS/HPF
2xF32T8-Electronic-IS

 :LOL: i bet the only one that will light is the electronic
I don't have an electronic 2xF40T12 RS easily available to add, Nor do i have a slimline 2xF48 or a high-output 2xF48 (but i do have a 2xF48 VHO)

That's interesting on the tests. My slimlines with 75W tubes will start in any temp but "rumble" terribly! I do not run the lights like that because the rapid restriking will destroy the tubes before long.

My preheat fixtures start in any temperature. I have gone out to the barn and fired them up at the coldest (below 0 deg. F) temperatures and they start. They are super dim, of course, but they start on the first click just like it was 70 degrees!

I haven't tried electronic ballasts in the cold, but I would suspect they will work.

@nogden i know exactly the 'rumble' thing you mention LOL ...sometimes they'll make a bug clunk type sound when first turned on too.

Yeah I woulda expected better with the 75W slimlines... maybe the old lights I got have crappy ballasts LOL (but they were used and free afterall)
 

Personally i can't blame anything for not wanting to work when its that cold out though :: i hate that weather myself

I've never tried freezing a Preheater, just assumed it would simply not work (maybe one needs to go outside next below-zero night )

I have some that fire right off when below freezing and some that flash a bit more, within the same fixture sometimes!