Lamp Base for USHIO HPL750/240


Hi Guys,
I wish to experiment with using thes lamps in some older luminaires. However, I don't seem to be able to source the lamp base from any one. Do you know where I can get a couple of thes from?

As an aside, why have they got a third pin on the lamp base?

(Ship) if you read this, when will your book be available?

(Anyone) I am curios to learn about luminairre design and the science behind the various types of builb. Can you recommend a good book?

Many thanks,
Dobbs :eek:)


Senior Team Emeritus
Premium Member
You cannot do a HPL lamp in a older fixture unless a ETC fixture. What supports the lamp is the heat sink and unless your older fixture has a heat sink mounting bracket - a ETC concept, it as a lamp won’t be retained in a fixture.

If it’s older ETC S-4 fixtures you wish to experiment with, yes you can install the HPL 750/240v in it but you will need to replace the fixture whip most likely. At least with the 750w/120v version of them, the origional S-4 fixture had 18ga wire feeding the lamp base which wouldn’t work so well over a period of time with a 750w lamp. Thus the “pins” attached to the heat sink. On the 750w/115v version, they are there to prevent a 750w lamp from being installed into a 575w fixture by way of wiring. Later, if you replaced the whip/base, it was permissible to drill out a hole for the pin, and with a certain type, grind off some alignment pins and the 575w cap would fit into and work with 750w fixtures and lamps.

In your case, the alignment pin is most likely to prevent a 115v lamp from being stuck into one of your 240v fixtures, or possibly the reverse of this to some extent as with the above. Basically, that’s the concept of the third pin a roll pin stuck into the heat sink. It’s there to designate it as a 750w lamp as opposed to a 575w lamp, and also there to designate it as a 230v lamp as opposed to a 115v lamp. It’s sometimes in a pinch done that this roll pin is removed but never a good practice to do so. As long as the wiring is upgraded, a hole in the fixture lamp base instead once drilled out to fit the pin is better practice - given the older fixtures have the new wiring as a general standard.

Lamp bases for a HPL are available from just about any theater supplier that sells either Sylvania/Osram lamps or ETC fixtures. Believe Osram is the current supplier of the all in one base these days though there could be more than one maker of the ETC licenced lamp base.

The science behind lamps can be very well learned by way of the Sylvania/Osram website in some excellent free PDF books on the subject. Look up any lamp such as your HPL lamp, go to further doccuments and you will see a PDF called something like “low voltage lamps...” Read it and you will know lots. Ushio also has “Dr. Bulb” if you can find the articles on the website. Good info on the science of lamps. GE has the “Lighting Institute” which has certain interesting articles about lamp design and concepts, Phillips also has some learning stuff available. Beyond that in official books on the subject, most stage lighting books have a few paragraphs or a small chapter on lamps. Also some larger electrical wiring books have chapters on lamps frequently - especially the really thick old ones. IESNA is otherwise the primary lamp technology publisher.

The main manual on lamps is:
Lighting Handbook, 8th Ed. Reference & Application, IESNA Handbook (989pp); IESNA Publications
ISBN: 0-87995-102-8 “Proven solutions for every situation. Everything to know about lighting-explanations of concepts, techniques, applications, procedures and systems, as well as detailed definitions, tasks, charts, and diagrams. This is the handbook to the established standard setting body for lighting. Expert contributions ensure technical accuracy. IESNA #HB

Lighting Handbook 8th Ed. Ready Reference, IESNA Handbook (223pp); IESNA Publications ISBN: 0-87995-135-4
This easy-to-use reference book is a concise, yet comprehensive, manual for lighting and represents a compendium of the most useful and essential information. Selected table of contents includes: Lighting terminology; Conversion factors; Light source data; Reflectance data; Transmittance data; Reflectance data; Transmittance data; Illuminance selection; Lighting calculation data; Lighting energy management; Cost analysis; Interior lighting survey procedures; Illuminance categories and values for diverse applications. This handy publication is small enough to carry in a briefcase and is a perfect supplement to the Lighting Handbook! IESNA #RR

After that they frequently have other titles on lamps: (plus lots more not noted below.)

The High Pressure Sodium Lamp, by J. DeGroot and J. Van Vliet (329pp); ISBN: 90-201-19028 “A detailed account of the theoretical background to the development and design of HPS lamps.” IESNA #PB

Illumination Engineering: From Edison’s Lamp to the Laser, by Joseph P Murdoch (560pp);
ISBN: 1-885750-00-5 “Provides a broad practical foundation in the science and mathematics of light and sight; teaches the skills and analytic tools needed for quantitative lighting calculations; describes measurement techniques and instruments in clear detail. Includes useful examples throught and a problem section complete with answers”. IESNA #PB11-94
Intermediate Level Lighting Course, IESNA Education Course (800pp); IESNA Publications
ISBN: O-87995-090-0 15 Chapters, covering: Mathematics, Vision, Color, Light Sources, Ballasts, Optical Control, Illuminance Calculations - The Lumen Method, Calculating Illuminance at a Point, Psychological Aspects of Lighting, Design Concepts, Computers in Lighting Design and Analysis, Lighting Economics, Daylight Calculations, Electrical Quantities and Building Electrical Distribution, and Electrical Controls. IESNA #150

Introduction to Light and Lighting, IESNA Education Course (51pp); IESNA Publications
ISBN: 0-87995-034-X Review from Home Lighting & Accessories Magazine: “It’s an educational book easing those who must be involved in at least a basic knowledge of lighting calming down the path. Before the reader is aware of it, he is already immersed in color rendering index and lumens per watt..., and after a brief explanation of calculations, the reader does not break into a cold sweat realizing he must be able to determine the coefficient of utilization. While the publication doesn’t answer all questions, it states so from the beginning, advising that should the reader’s interest be piqued, there’s plenty more from IES to satisfy curiosity.” IESNA #ED

The Euro system also has their own line of lamp books/manuals.

I for instance have my copy “Determination of the ratio of the luminous flux of discharge lamps to the luminous flux of reference incandescent lamps.” This is from the “Commission of the European Communities” bcr information - applied metrology report EUR 10574 EN....

Interesting text, not very useful overall but it was an interesting read. Osram has other PDF books on arc source lamps etc. also by way of “further doccumentation” as a quick pick pull up when looking at any lamps. Phillips and GE also have some extent of readings for free on their lamps by way of pulling up a lamp and clicking on further readings or topics. They also have news and other literature that you can learn from. The GE “Lighting Institute” has an on-line lamp course you can take. Ushio of course also gives out some info but much of it was published as pamphlets and their on-line website is still attempting to catch up with the 21st century. GE used to give amazing info about lamps. The “GE Spectrum” catalog from a few years ago that was like a 2" binder, had nothing but info about lamps - lots of stuff to read.

For the most part get any brand and all brands of catalog - general lamp catalog and photo optics catalogs, and mini-lamp catalogs etc. You can probably get them on-line sent out to you or from your lamp supplier. Read it cover to cover. Amazing what you can learn by not skipping a note in just a general line of lamp catalog. Beyond that, there is other brands such as Radium or Reflekto amongst a ton of companies out there with lots of other info on lamp design by way of their own notes or press releases with a kernel of knowledge about lamps you might find of interest.

As for my own book.... let’s put it this way, I’m at least a year and a half behind schedule in keeping my lamp specs “appendix” chart up to date which I use on a daily basis at work. Just got a new set of literature from Osram today to go thru lamp by lamp in discontinuing and or adding changes for that company alone. Constantly find new sources of lamp manufacturers or new lamps coming to the market. In the morning I’ll get some new Ushio catalogs etc. Lots more reading to do, I don’t yet own any IESNA books that I should probably read etc.

I work 50 to 60 hour weeks in putting bread on the table. Would probably need a year off in writing a lamp book in getting all the studying, editing and lamp chart appendix done were it feasible at this point. Otherwise in theory, if I retire by like 70, that’s only another 32 years away. So... it’s something to work on but all I can attempt to keep up with at this point is my appendix “lamp specs” chart in getting it current at this point. After that a book on lamps... anyone know any rich people that want to give me lots of money to take a year off to write a book? I would love to stay home, work would hate it of course were I to take a year off or more than a day off. Stuff just kind of piles up when I’m gone.


Ship, 'You da man', Thnaks for taking the time to answer my questions. Your answers are very comprehensive and just what I was hoping for.

I hope that someone 'rich' has theh foresight to give you an advance, which will allow you to complete the book. The (Stage Lighting) world will be a better place if they do :eek:)

I suspect that guys like you never retire, as it is not just a job - its a passion.
Many thanks,

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