You may know that I have a Universal USB-1024-14 sign light ballast. Recently, I've decided I want to put it to use. The design is that of a basic industrial strip light, it'll be made of 1/16th in thick metal for the main body and reflector, although a separate flat piece made of 1/8th in thick metal will hold the ballast and hooks and will be connected to the rest of the fixture via mechanical means. I plan on having it operate 4 F36T12/HO lamps, using R17d lamp sockets. Any ideas or suggestions on making this become a reality? I will be designing and manufacturing it myself, but any idea on how to get the measurements right? I want to get the measurements right one the 1st or 2nd time in order to not spend a ton of money on prototypes.

Yeah it seemed like it would be fairly easy for a manufacturer to modify one of those designs for LPS, modifying the design to match the current of a LPS lamp and also modifying the wiring shouldn't be take too much effort.

LPS would work well with Instant Start FL ballasts matching by current, and those are available for 120V

If transformer is a given, the higher Voc has only indirect effect on the efficiency :

 - The difference between Voc and Varc (Vballast, with the root formula) is dropped on the ballast impedance. As the ballast impedance is not a resistor, this (in theory) does not waste any power even when Vballast is high

 - The higher Vballast requires more turns in the ballast's secondary winding. If instead lower Voc would be used, this would require less turns, freeing up space, and allowing the remaining turns to be made with thicker wire, reducing its resistance and therefore losses. (With some relocation of the leakage paths in the core, there could be room made to push some of the wire gauge improvement to the primary winding as well)

Maybe the difference (via the ballast wire gauge) was not deemed significant enough, and they preferred to eliminate the ignitor instead

(And maybe this was a design choice from the early days of the technology, that just wasn't changed because dont fix whats not broken, even when in later years the cost of ignitors went down and copper and electricity went up)

Yeah my understanding was that LPS was a niche enough item in North America that ballast manufacturers never bothered to adapt the choke + ignitor setup common in newer European LPS ballasts to North America.

Same goes for electronic LPS ballasts. It's unfortunate since a lot of lower power leak transformer based 120v LPS ballasts were fairly lossy and resulted in a fairly low system efficiency compared to HPS. Even LPS ballasts designed for higher voltages such as 240v, 277v, 347v, and 480v remained based on leak transformers. It's too bad electronic LPS ballasts were never developed for 120v as well. I could see why the choke setup never made it here due to insufficient OCV on 120v but it seems like a electronic ballast might have been easier to adapt.

Now I suppose if LPS was more common here, something like a PSMH HX ballast might have been developed for LPS, only a modest step up to avoid the lossy leak transformers and then a ignitor to provide the starting voltage. I suppose ballast manufacturers did the math and figured the cost of NRE for developing such a ballast for 120v was more than any potential increase in sales compared to the existing leak transformer ballasts.     

@RRK
Yes, they really didn't catch on here, very unfortunate.

@Ash
I should have specified:
I don't mean having choke ballasts on 240V, that would just be barbaric (ahem europe) just kidding
I mean just having CWA (ew) or HX autotransformer ballasts that output a lower OCV but in conjunction with an ignitor. Choke ballasts are barely ever used here, presumably because of the wide range of voltages we have available. Even the 120V HPS chokes are kinda rare to see.

I have seen those open-air ignitors on Ebay, those are disgusting. As much as I like to be able to see what is inside electronic devices, ignitors are definitely ideal candidates for potting.

Many US luminaires used the same type transformer ballasts for HPS as well, despite many of them running on 240V and 277V

And many also have ignitors made in open frame, a bare conductors high voltage circuit operating in the filthy and damp environment inside the gear compartment of a cobrahead. Not great reliability either (and by far more likely cause of failure than internal failures of electronic components)

So, the consideration was apparently not efficiency and not reliability, but something else. Maybe :

 - Wanting an universal ballasts that includes also 120V as an input voltage option. This requires a transformer, and if so, just add taps for the other voltage options. (Still does not explain why not make completely separate, and more efficient, ballasts for each input voltage range. Even the 120V ballast would have good efficiency improvement and cost reduction from not having to contain additional winding for the higher voltages, unused at 120V but taking up space, that could be used for thicker wire in the other windings instead)

 - If the ballasts are CWA, better resilience to line voltage fluctations

The "ping" sound starters make when starting lamps, does show that the starters do in fact snap action

For how long it stays shorted depends on the shape, thickness, etc of the bimetal strip. In particular, how far it can tension back when cooling down, before the force tears open the micro weld that happened between the contacts due to arcing when it was closing

Some starters have the contact spot of the bimetal strip bent in a specific shape in order to control the surface area of the contact spot, and therefore strength of the weld

It's mercury lamps, the starting reliability is not affected by distance

I have a wild guess, but i dont think this was the reason, or even a consideration. A pole in the median is more likely to be hit by cars, and not having a ballast can up there is one less thing that can fall down into a car in case of an accident (into the windshield, etc) and cause an injury

The outstanding performance of HPS for outdoor lighting does not come down only to Lumens, but to our eyes and brain ability to complete the full image from an otherwise very unbalanced input (a scene lit by non uniform, near monochrome, orange light)

(Incidentally, those is the very same reason why LED outdoor lighting achieves the exact opposite for our eyes, but might actually perform well for a video camera)



Dynamic range :

Our eyes have very wide dynamic range. Every time you look from an outdoors location under bright sunlight (100000 lux and higher) into a dimly lit lobby of a building through an entrance door (can be as low as 100 lux), you are seeing at the same time two areas with 1000x difference in the average light levels, and able to perceive what is it that you see in both of them

Under HPS (or really pretty much any) outdoor lighting, there are areas under the light which are brightly lit, and areas away from the light that get dim lighting. HPS does not ruin night vision, therefore it allows us to make use of huge dynamic range

Video cameras of the 80s have awful dynamic range. Even today's cameras are a far cry from the capabilities of our eyes. It is possible that filming under HPS would capture a scene which is well lit or even clipping directly under the light, but have an abrupt cutoff area beyond which it is unable to capture

Under Mercury light, the light in the area to be filmed have possibly higher uniformity and lower intensity, allowing the camera to see a wider area correctly within a single brightness setting



Color rendering :

The tiny amount of blue and green in HPS spectrum is all it takes to provide us with full color vision

Our brain understands that the light itself is of orange color, and extrapolates from the little blue/green the eyes see to understand what each surface in the scene would look like under natural light. Then, it is matched to things we are familiar with as reference

A video camera does not do any of this. The image is quantified into 3 color channels of an image sensor (which sensitivity spectrum is completely different from any cells in the eye), each of them is stored on and read from media (with or without correctly matched gain), and finally displayed on 3 color channels of a screen (with light spectrum that have nothing in common with the original spectrum at the scene, or even with the camera sensor)

Now, instead of the 589nm peak of Sodium light + little more info in other areas of the spectrum, we are presented with a scene with "the same colors" but is actually recreated either with wide emission spectra of Green and Red phosphors (CRT), or is filtered down from the emission of Fluorescent or LED (LCD), or UHP Mercury lamp (in the cinema), made from data already corrupted by the camera

Our brain won't know what to make of it, and either won't, or won't successfully, do what it can with the real life scene

And provided the awful dynamic range, the blue and green data will probably be nearly fully lost already at the camera anyway

With Mercury light which is white to begin with, there is much less to go wrong here