Beautiful ballast there! Low power factor i'm guessing?
How can you tell the difference between Low, normal, and High Power Factor judging on how the lamps start?

Nice find! I have two of these, one is a long leaded one that's currently in use and the other is a replacement ballast I picked up shortly after they got banned. That mercury lamp sounds interesting too.

@streetlight98: I don't know there is a way to tell with lamp startup... but with an EOL lamp (with just one bad filament) you can - LPF/NPF they'll light/sorta flicker at around 50% brightness, HPF they'll just have a dim glow.

this ballast is high power factor..... 2 ways to tell, it says so on the ballast but a wire is kinda in the way and usually the line current is .73A or higher that's usually a good indicator .

I know different types of HID ballasts have different flash patterns and fluorescent ballasts might be the same too.

I thought somebody said that LPF lamps flickered more than HPF or visa versa...

HPF ballasts have a capacitor that not only corrects the power factor but also acts as a rectifying protection. A capacitor can conduct AC, but not DC (it'll charge one polarity, then the other, the first one again and so on). A rectifying lamp causes the cap to charge in only one polarity since the lamp conducts in only one direction. So as soon as the cap is completely charged (which is pretty fast), almost no current flows in it, preventing the lamps from working. See the page 48 of this document and you'll see where the capacitor is located. There's one between the red and yellow leads, but I think it's an RF filtering cap or starting aid. The other cap is located just before the secondary winding.

The little flickering you see with HPF ballasts is (I guess) the leakage current of the capacitor.

Ahh I see... Also, does the starting aid in RS ballasts ever die? Would leaving a lead lamp in a RS fixture cause the starting aid to keep striking and in turn kill the ballast?

That cap can short, and it would prevent one of the lamps from working by literally bypassing it. But I don't think leaving a dead lamp would cause it to fail.

Yeah many rapid start fixtures I've worked with have had dead lamps for years and worked when new lamps were installed, only one lamp goes bad but when they both sit usually the good one dies too so i end up replacing both unless it just burned out
I have 2 ballasts that are valmont and only work when wired for 1 lamp because the starting capacitor is fried...when it went bad the lamps were ok!

How common is a dead starting aid in a RS ballast compared to a preheat or a HPS or PSMH? I'm guessing RS starting aids are more heavy duty given the fact that they're not replaceable...

Not common for them to fail...usually the ballast will go open circuit or short at EOL...but totally different principle then what an HID ignitor uses, they have an electronic circuit that shorts out the ballasts output for a brief period of a second to generate a high voltage pulse...some MH quick restrike ignitor are 5KV!

Ahh i see now... Overall, I think magnetic rapid start provides the longest lamp life. Do preheat ballasts still cause lamps to rectify in cold weather like RS? do preheaters start lamps better in the cold?

Yeah the only problem is it doesn't work well below 40F or humid conditions(unless it's higher OCV cold weather ballast (which i have one) the flicker isn't rectifying when lamps are cold. ..its just stations. .preheat is rated down to 0F

So lamps on a preheat ballast won't flicker when it's cold unless it's under 0 degrees?

Well they'll blink a bit more but start within 10 seconds (unless bad starter) honestly i have not done many tests with 4foot preheat in the cold but the smaller lamps.do very well. ..slight flickering until they warm up especially on a low mercury lamp

I guess i'll try it this winter with the three 4ft preheaters in my cousins' grandparents' garage. They will all work by winter as long as the lamp i bought are good so i can find out myself. I tested the lamp i bought, but i acidentally dropped a few (i was holding them vertically by the cardboard cover over the endcaps when the glue failed and the tubes slipped out of the cardboard and hit the floor by the pins. I put my ear up the lamps and flipped the lamp upside down and didn't hear anything loose so i'm hoping everything's okay.

yeah they should be ok, one time i tapped a sylvania VHO lamp and broke it near the endcap, it had a hairline crack and wouldnt light anymore, still have 2 left and glued the ends to prevent any problems with glass cracking

I've tested a 4' preheater in -18F and it fired up (just very dim)
Rapid-start didn't go in something around -2F (but the fixture also wasn't grounded)

I know that they made some cold start RS F40 ballasts a while back with a higher OCV for easier starting.