These are called NEMA fixtures, which use clip-on optics. That one has an acrylic bucket refractor optic, but these were also sometimes used with gumball glass refractors or even a radial wave reflector.

It's a little hard to tell from the photo, but it was most likely made by American Electric Lighting or Cooper (earlier versions of the Cooper were made by Westinghouse). Both the American Electric Lighting (L series) and Cooper (RMA series) versions are still made. GE also made a similar version in the 1960s and 70s (model 101SA).

That fixture most likely dates from the 80s or later if it's HPS.
Mercury vapor NEMA heads like these were made from the 60s up until 2007.

Earlier NEMA heads were made as early as the 1950s possibly 40s but usually had a more rounded shape to them.

I suppose this model is around 50 years old. I've done research, and it doesn't seem to be listed anywhere on the internet.
However, where I live, it's relatively common and is usually seen in older areas of town. They are always mounted on wooden
poles. They are always either mercury vapor lamps,or HPS lamps. Help identifying the model or the year in which it was
produced would be greatly appreciated!

I may end up with a currently non-functioning LOA undercabinet fixture. It takes F15T8 lamps. I could probably put an F15T12 in there as well. My question is has anyone converted one of these to preheat when the cheap circuit board "ballast" craps out? It looks like a preheat choke would fit inside. I could drill a hole for a starter socket and use one of those clip-in style starter sockets.

220V arc is too much for 230V mains (even when peak 325V looks like 100V room), there are reignition spikes that needs the mains to be almost double in rms (so nearly tripple in peak value) than the arc voltage in order to work reliably.
So the 220V arc lamp needs to be fed by 400V from across the phases. But anyway these use to be 1kW beasts, with resistive that means other 2kW in losses. Are you sure you want to feed 3.5kW?

Mine is a single bulb RF fixture I believe dates back to around 1941.

The fixture was under a table in an old attic from what I was told
The seller would not ship the light ,and I can’t blame him,

I Love that Light !!

I drove all the way up to Massachusetts from Houston Tx to get that Light,
I’ll never forget that trip,

Oh yup mybad. it's a model 13 yes.

Thanks, I will buy some generic MV lamps for experiment with it    .

Thank you  ! You can get any formula or relation for calculate the relation for a 220-230V arc, in a 220V 10A 50Hz current?


Thanks.

My Westinghouse RF luminaire isn’t tilted in any way. The tubes are completely level.

E.g. the last post showsa rough estimate, ithas to be fine tuned by experiments.