I think that assumption comes from the dominance of mercury vapor back then...I've also seen old catalogs mention HPS and MH options too.

So, in this case, would the 425W H40 mercury vapor lamp still be overdriven on a 1000W M47 probe start metal halide CWA ballast even if the series capacitor value is near zero microfarads or could the ballast suffer possible overheating?

Alternatively, it may seem that a last resort for running these lamps could be to source a step up transformer with a 480V secondary and possibly do a series of trial and error tests of series choke ballast combinations until the lamp is running at the proper 1.7A operating current and 265V arc voltage drop?

I would love to see someone find a H40 425W mercury lamp, never seen one in a collection I dont think sadly, but you cant fudge a M47/H36 ballast this much, you can do it fine for a 700W mercury lamp, but there is a limit to how far you can take things.

your best bet for running a such a lamp like this in 60Hz land would probably be across the red and blue wires of a 2 lamp F96T12 VHO ballast, 1.5A is likely good enough to run the lamp up to near enough full power.


(interesting brochure/technical document BTW interesting to get some detailed info on the 6.6A series mercury lamp, years and years ago someone uploaded a period picture of a lady holding a tray of early westinghouse mercury lamps and there where many interesting types there PS35 shaped 175W sorts and the afromentioned H17 425W and H24 6.6A ~400W~ types, the later of which with its 70V arc voltage you could probably get away with running on a series choke off 120V)

Hi all,
I am new to this site and excited about it! I recently purchased three 26W Low Pressure Sodium Vapor Lamps. I'm a theater designer and am interested in using two of them in a show I have coming up in a few weeks. I am very new to the world of SOX lamps and am having trouble finding the correct Ballast for them. I was hoping to get an electronic ballast because they seem easier to find/cheaper and I don’t need an ignitor but am unsure which one to get. I know it needs to be at least 26Ws but can it be more than that? The system I’m running it on is 3 phase power, 120v, most bulbs we run on this system are 750w so I’m not really worried about getting power to it. Mostly just how to get it to actually work. I’m attaching a link to the bulbs below.

https://www.ebay.com/itm/186339138191

Also if someone knows what kind of base is required, It says it’s E26 but I’m not familiar with the bipin setup, do I need worry about the voltage since it is a different base then a typical E26?


Sorry for the long list of question
I appreciate any and all help!

Hello welcome to LG

the 26W SOX-E lamp has quite the wide current operating range 0.3A-0.6A thus the easiest method for you would be to use a standard F32T8 (or F96T8) 2 lamp instant electronic ballast, with the 2 outputs tied together should run the lamps within their rated current range, and by tie the outputs together, this is known as wiring the ballast for overdrive, this is where you take the 2 wires of the same colour and tie them together, they go to one lamp holder terminal, and the lone wire of a different colour goes to the other lamp holder terminal


the ballast you link to is not quite powerful enough to drive the lamps properly, but this ballast for example should work well https://www.1000bulbs.com/product/2178/BF-WH3120LC.html you will want to use the F48T8/HO wiring diagram for it https://www.fulham.com/WDpdf/wire3.pdf see here for other wiring diagrams if your curious https://www.fulham.com/contact-us/wiring-diagrams/


but it does not have to be a Fulham ballast, most sorts of US Instant start F32T8 2 lamp ballasts will work for the role, I mention this just incase you happen to already have something kicking around


I hope this helps

I found this that I thought might work

https://www.1000bulbs.com/product/2165/BF-WH33120CC.html?gad_source=1&gbraid=0AAAAAD_uQn7YI1jvygDIs4x3Qp1tOs-cN&gclid=CjwKCAjwl4yyBhAgEiwADSEjeHZ0gtR7yAfZpMSlaMwu9m1LYrFl6wZ8Fb_fD_37RRYATZz9R3wgmhoCDbAQAvD_BwE

Hi,
I don't know anything about ballast, I'm afraid. I've found the original planning application, that contains a reference to 'ballast' - I'll attach that and hope it means something to you.
The fittings and everything other than the bulbs were removed by the lighting contractor who converted the floodlights to LED.
And I've also found another photo of the bulb, if that's of any use.

If you watch Facebook Marketplace they do pop up sometimes.

This is an interesting one?, in Cheshire we’d pronounce this as it’s written ‘max-im’ !  , good that you have cleared up the proper pronunciation though.

Some of our US members will be able to advise you correctly of which ballast to get, and which tappings to use. 

Thank you for such a quick answer! I am in the U.S, so this is all super helpful. Just so I made sure I understand you correctly. I should look for a fulham workhose ballast that is 35W. Does that usually include an ignitor or is that a separate piece of gear I need to buy?

Also I appreciate the help with the cap! I’m going to see if I can find one in person just because I’m in a little bit of a time crunch.

I may have more questions but I will make sure to send pics once I get it all set up.