Howdy again!

Went to a huge "junk lot" type store today with a buddy. It's a huge place in Plainview, TX, and we just wanted to go poke around and see what all vintage electrical equipment they had. They have a few light fixtures, that are interesting, but we stumbled upon this cool thing. It is stamped "Revere," and from what I have researched, it appears to be an external ballasted "Endoval." It's obviously a mercury vapor unit, and I am assuming it was a 400W unit, as the bulb appears to be of that rating. The gas tube is way too big to be 175. Perhaps 250? Also, there are several wires coming out of the ballast which leads to believe that this may have been a 3-phase unit? Were these even made in 3-phase? Way too many leads for to be single-phase 110/220. It was pretty dirty, but the glass is free from chips and scratches. It was mostly just dust on the inside of the globe. It's sat in the dust of West Texas for many years! My friend is going to clean it up, gut it, and put in an LED of some kind. and mount it in his backyard. He already has an old Westinghouse "acorn" light in the front yard he converted into a low-wattage LED fixture.

Any info appreciated... here is a pic.

nice looking lamp and with a little bit of cleaning it will more then likely last a very long time yet, now I don't know anything about it, but its not three phase unless they did something crazy and in theory you could take three phases and feed three equally sized lamps if you connected the screw shells together in a Y and they would operate without a neutral, but if the sparky got caught doing that they better be looking for a new job, and I don't know if this would even work with a MV but it does with incandescent lamps.

So I would be going with it's a single phase ballast, the extra wires might be for a photocell or even a dual capacitor dimming relay control or some kind of incandescent back up lighting...

By chance do you have a photo of that acorn lamp ?

There haven't been any 3 phase lamps in use. They were developed and engineering samples made, but never went into production beyond that

This luminaire is meant to get a single voltage, most likely one of : 120 208 240 277 480. This can be achieved either by using Phase-Neutral or Phase-Phase voltage of a suitable supply, or by a transformer/autotransformer. The luminaire does not mind

If you want a proper smaller light out of it, your best choice is using a Pulse Start MH lamp with suitable gear

By chance do you have a photo of that acorn lamp ?

Sorry it took so long for the response. I went out of town for a week right after I posted this topic and haven't had a chance until now to respond. I have no idea why I said "acorn" light. I meant to say "teardrop" style. Here is a pic of it on a short pole. It has an LED in it and has been rewired for 120V.