Hi, I rewired and cleaned up a brilliant old Thorn HIPAK 400w mercury vapour fixture. When switched on, the lamp glows a very faint pink-orange colour. I'm assuming that this can be fixed by simply replacing the lamp, and is not a problem with the ballast.

I originally thought they were Wide-Lite cubes but it looks like they're something else. I wonder what lamps they used...almost looks like GE's short lived panel F lamp.

Not that I know of.

According to this site, there are some in active service in Orange County, NY. And supposedly some made it into the hands of collectors.

@ScienceGuy722 — there are plenty of Scribd downloaders out there. All of which scrape the original PDF document from Scribd's servers. You have to be completely taken in by the system of 'ask no questions and do as you're told' to not seek out (or develop your own!) free alternative to supporting the mega corporation.

https://youtu.be/y51VUsotZe4?si=7qyI61gdq35cRBgu

 I have an early 80's GE brochure which talks about Detroit's Tigers Stadium being converted to 550 MVR1500's from the original 1328 1,500 watt incandescents . I don't think I've ever seen MV used in a stadium , just incandescent or MH .

That is indeed how i imagine it. There is (unbalance L) + C series circuit, which does not have to be in resonance but to pass the desired current for filament heating. Then the rest of the winding steps up the voltage

The phase diagram may vary somewhat between manufacturers - Eltam use a different capacitor value than UK manufacturers. Also, i have seen moderate++ success with Eltam ballasts starting 36W T8's, something which is not supposed to work according to descriptions by UK users

Would definitely like to dig up mine and provide here whats possible

Sure there may be some multiple variants of SRS circuit tuning, for the circuit in Atlas book, in staring mode the voltage on the primary winding is just 40V so apparent 'resonance' is really weak. BUT if you look at vector diagram you'll see the voltage at choke winding and at capacitor is in-phase, which should not be a case for a series resonant LC tank. So may be a better model for the circuit will be a step-up auto-transformer (fed by a capacitor current) made from primary and secondary windings unbalance?

If the winding would be assymetrical, then it would matter which winding is connected where. But as I understood, the wiring diagrams do not explicitely mention that to matter, so my guess was they are symmetrical.
Plus SRS was developed in the T12 time and T12 were happy with about 200V for ignition with warm electrodes, so you don't need any voltage boost there, even with 220V nominal mains.
And I doubt the design won't prefer some extra "poka-yoke", when there isn't anything explicite to not allow it.

only checked one of my SRS ballasts so far, a Multi-wattage Parmar 5ft-8ft 65-85W jobby

https://www.lighting-gallery.net/gallery/displayimage.php?album=lastupby&cat=0&pos=27&pid=261057&uid=476#msg889328

and as you can see from my comment in the upload above, the windings are not of the same DC resistance so I would go out on a limb and say they are asymmetrical

This damn circuit is quite hard to understand, despite being that simple. Vector diagrams in Atlas book from @LightBulbFun help a bit.

Despite a loud name, not much resonance is going on here. For a simplified variant, one can ignore filament resistance and assume the windings are the same with 100% coupling. That way, on startup, the circuit degenerates just to two filaments in series with a capacitor, powered from mains, and in working mode, (surprise!) to just a trivial lag single choke circuit with a PFC capacitor across THE MAINS (!). A classic circuit theory approach where you are allowed to mentally connect the nodes with the same potential helps with the analysis.

From Atlas diagrams, though the windings have some slight asymmetry, and sure coupling is not 100%, which will give a weak resonance kicking OCV up a little.

I find it interesting that claims are made that there is no or little resonance going on when the atlas technical booklet explicitly mentions that they work by resonance to boost voltage for lamp starting

in particular what do you say about the comment in the technical booklet about the voltage rise coming from the adding of Vc to Vs? 



also should be noted SRS ballasts for 18W SOX lamps where quite common (as they officially require about 300V to strike, so an SRS ballast was seen as a good way to generate that in a compact low-loss-ish ignitor-less setup that also has the added benefit of inherent PFC correction)


https://www.lighting-gallery.net/gallery/displayimage.php?pos=-116224


(I was always a bit annoyed how they tied the coils together into a single terminal like that, so you cant use it with a regular 2ft tube or 18W-24W PL-L or 28W 2D if you wanted to LOL)

This damn circuit is quite hard to understand, despite being that simple. Vector diagrams in Atlas book from @LightBulbFun help a bit.

Despite a loud name, not much resonance is going on here. For a simplified variant, one can ignore filament resistance and assume the windings are the same with 100% coupling. That way, on startup, the circuit degenerates just to two filaments in series with a capacitor, powered from mains, and in working mode, (surprise!) to just a trivial lag single choke circuit with a PFC capacitor across THE MAINS (!). A classic circuit theory approach where you are allowed to mentally connect the nodes with the same potential helps with the analysis.

From Atlas diagrams, though the windings have some slight asymmetry, and sure coupling is not 100%, which will give a weak resonance kicking OCV up a little.