Hi all, last night I did the first test run of my 400 watt Mecury Vapor (WH 33-1 GL/W) using a M59 ballast. Had my DVM hooked up and found the startup very interesting. Was surprised to see the voltage drop so low right after plugging it in. The Hz was also bumped up. BTW I checked the ballast by itself (no load) and found 302 volts on the lead to the capacitor. Also found a light .55 amp load when idle.

My plans for this lamp are to make some type of display platform for it and back light it with a red PAR16 LED lamp (looks great inside the house) then if anyone wants to see it go I will take it outside and light up the whole back yard.

Fun project and I will post follow up with a picture of it with the red glow.

 

Nice find on the /W mercury vapor lamp. These particular mercury vapor lamps are very rare and well sought after.

Here is a picture of the lamp at full power - 22,000 Lumens with a glorious green glow 

BTW the voltage settled on 133 volts after it warmed up.

How many of them were you able to get ? I remember you saying your friend had a few of them .

I only have the one but I will let you know if my friend decides to let go of some more.

Interesting observation, what you have measured is a parameter known as the Vmin of a mercury-based HID lamp.  Almost all mercury and metal halide lamps start with a volt drop of something like 20-25V, and during the first 30 seconds or so the voltage will drop to something in the region of about 12-20V.  The measured minimum voltage can be correlated directly to the concentration of hydrogen gas impurities in the arc tube, and is one of the most valuable indicators of lamp quality, efficacy and the lifetime it will obtain.

Lamps with the lowest Vmin are the best and the manufacturers make extensive efforts to refine the manufacturing process to achieve the lowest possible Vmin.  It is often used as a quality check during production - individual arc tubes whose Vmin is too high are scrapped because their lifetime may not meet expectations.

That's fascinating information James, you have me intrigued now. I shall have to do tests on some of our MV and MH lamps when we next light them up

Thanks for the reply and info. Very informative and interesting.

Thank you and keep me informed .

Came up with the idea of making a small pallet to mount the light and ballast on. The goal was to make something interesting and different that would be compact and easy to pick up. Have the small LED PAR16 red light mounted and I'm quite please with the results. I now have a one of a kind low level light for indoor use and can take it outside and light up the whole back yard when to mood strikes.   

Very well done, you should post those on the gallery. I make ballast boards like these, and hold the lamp in laboratory retort stands like this

For long SOX lamps, we use two stands 

I must remember to measure startup voltage and current next time we run up an MV.

I took a look at your wall of ballast, nice collection and well done!

Thanks, it's satisfying. I originally built the first couple for a public demonstration of how discharge lamps worked that unfortunately never happened. But the seed was sown so the rest followed. I confess I'd rather like to build some gear boxes like these from member FrontSideBus, but the enclosures are rather expensive and I just can't afford to do it at the moment