I am building a monochromatic lamp with the use of a low pressure sodium (LPS) lamp. Through research I understood I need a specific ballast for such a bulb.

The examples I found on the net feature a LPS bulb but only the 35W one. The ballast recommended for the 35W bulb was the Fulham Lighting WH3-120-L Workhorse 3 Adaptable Electronic Fluorescent Lamp Ballast, 120V, 64W max.

Unfortunately I require the 90W bulb for the project, as apparently it is possible to mount the bulb horizontally. I tried to look for a ballast for a 90W LPS, but often found products that are five times the price of the first mentioned ballast or that are unavailable in my area (I was only looking with those specific keywords.)

My question to you is: what kind of ballast should I be looking for for a low pressure sodium lamp of 90 watts?

  • 1
    It would not be absurd for a 90W lamp ballast to cost 5X what a ballast for a 35W lamp costs. Annoying, but not unusual, as the cheaper one may have far more mass-market usefulness leading to more production volume leading to economies of scale.
    – Ecnerwal
    Oct 28 '20 at 2:52
  • Here is the spec sheet for the WH3-120-L. Note the lengthy list of lamp types it supports, noting the table which indicates watts, current, PF, BF etc. for each lamp. Do you see your lamp on the list? Oct 28 '20 at 3:01

If I were you I'd be looking for a 90-watt low-pressure-sodium ballast.

That's pretty much the google phrase, though "SOX90 ballast" may also yield some fruit. Apparently SOX is the slang for this type of tube.

You know, you can get LEDs that emit a single color. In fact, LEDs were single-color for most of their existence. You'll have trouble beating SOX for efficiency, but LEDs will certainly be better for availability. The easiest way to get single-color LEDs in a vaguely consumer-buildable form-factor is in 12V LED strips.


Here you go! https://www.youtube.com/watch?v=SQb8qnioXBs

Build for a 90w LPS fixture.

He shows a Fulham WH5-120L Workhorse 5 Ballast, $35, ballast for the 90W LPS bulb.

Great project - I'm working on a 55W lamp now!

  • While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. - From Review
    – Chenmunka
    Sep 10 at 7:43
  • @Chenmunka -- I think they already did what you are asking for :) Sep 10 at 11:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.