A Lithonia 2xF40 ceiling fixture...pretty average unit, LPF Rapid-Start ballast.
But i gave it alittle an upgrade for power failures...
Shown unplugged here :)
Ah, the infamous, loved-and-despised "basket" wraparound style fixture! I have one, sans diffuser, and sorta like it since so many people despise them!
Mine has one of those .47a-with F40s-line-current Advance LPF rapid start ballasts, running a pair of mid-90s GE 34w cool white Watt-Misers. Much better than F40s on ballasts like that!
Some are pretty much optimized for those 34w lamps, but the older ones are far from it...yeah they overheat and trip their thermal cutout. Same goes for the 1-lamp shunting "trick". (The rule of thumb for that with any ballast is "If it won't like 34 watt lamps it SURE won't like that").
The ones with the .85 amp line current seem to be the ones rated only for 40 (or 25) watt lamps and that will cook or at least thermal cycle with 34 watt lamps. Newer ones, which have a really increased line current (and brightness!) with 34 watt lamps listed on the label seem great with 34s. Look for a .82a-ish line current (with 34s that is). I have a 1998 MagneTek in use which is .675a with standard lamps and .82 with energy savers (counterintuitive, huh?) as well as an Advance (in one of the above-pictured "basket" wraparounds) which is like .72a with 34s and .47 with standard lamps!
Mine has one of those .47a-with F40s-line-current Advance LPF rapid start ballasts, running a pair of mid-90s GE 34w cool white Watt-Misers. Much better than F40s on ballasts like that!
This is the only one I've ever seen.
I'm shocked that you can run 34w lamps on that LPF ballast, anytime I've ever tried running those type of lamps on a LPF it overheats & shuts down.
The 1-lamp 'trick' will work... if that one lamp is a full wattage HO 8-footer (ofcourse it'll be pathetically underdriven)