When I initially learned that probe start metal halide ballasts in North America were compatible with most mercury vapor lamps of the same wattage, I initially thought that it was the coolest thing ever. However, when I did learn about high pressure sodium retrofit lamps like the Sylvania Unalux lamps that are intended for use on mercury vapor ballasts, I have felt disappointed in learning that they were incompatible with CWA ballasts since most North American probe start metal halide ballasts are CWA and that I appreciated the deep red glow that they emit when warming up. I wonder if any other North American collectors recall feeling disappointed when learning that the Sylvania Unalux high pressure sodium retrofit lamps along with many penning start high pressure sodium retrofit lamps were incompatible with most probe start metal halide ballasts?

Since then, I have developed a preference for collecting HX and reactor type mercury vapor ballasts as I have learned that so many other HID retrofit lamps for mercury vapor fixtures are incompatible with CWA ballasts.

I was incredibly incredibly dissapointed! This was before I even knew the real operating characteristics of either type of ballast, but that put a bad taste in my mouth about CWAs that only got worse. I'm not a CWA fan in case that wasn't evident lol .

I would love to see a long term study done with CWA and HX ballasts and how they perform with identical lamps with 95%, 100%, and 105% line voltage. I'd like to see how their lifespans compare. Anyway that's besides the point and nobody's gonna do that.

And yes of course American MH ballasts over 150W (I call it the 150W-dividing-line-of-stupidity, which applies for many things with HID lamps) are CWA, but I believe the situaiton is even worse for MV. I have even seen 100W (maybe lower I don't remember) MV ballasts that were CWA, which is ridiculous! Really your only reasonable option is to try and find a MV choke ballast. Or of course you could try and get Japanese gear or rare American gear like you do (very cool btw).

I should make a whole post about the 150W DLOS some time. Anyway yes, very dissapointing, especially to see with American retrofit products. "This product works with MV ballasts! But only the ballasts that make up a tiny minority of US installations". Whatever, you can probably still test them out with CWA gear with constant attention and variac-twiddling to keep the specs right.

You should be on the lookout for unsaturated retrofit lamps, like the Philips Retrolux or Eye Sunlux Ace, which are compatible with MV/MH CWA ballasts.

As far as I know, the only Iwasaki high pressure sodium retrofit lamps in particular that I know of to be compatible with CWA ballasts are the “Sunlux Super Ace” and “Sunlux Ultra Ace” lamps with the “CE” and “LC” suffixes. While the “Sunlux Ultra Ace” “CE” suffix lamps generally have probe start metal halide ballast compatibility in addition to mercury vapor ballast compatibility, I have seen that the “Sunlux Super Ace” lamps usually have an OCV limit that makes them largely restricted to mercury vapor HX, reactor, and CWA ballasts with an OCV under 270V or so unless the fixture is rarely turned on or there are minimal power interruptions. However, I have seen evidence that Iwasaki lamps designated as simply “Sunlux Ace”, but have the “LX”, “L” and “LS” suffixes are still only compatible with just HX and reactor ballasts only.

I knew about it before I bought one of these lamps but I did find it silly that a lot of HPS retrofit lamps were designed only to run on ballast types that weren't that common. Aside from the 150w retrofit which can be safely used in most yard lights, finding a luminaire with the correct ballast and doing your due diligence to check the ballast type isn't the kind of work that a drop in retrofit should need. It's too bad the CWA compatible retrofits aren't that common and you need to jump through hoops to review datasheets to make sure they are.

The 880w H36 retrofit is probably the worst, since the most common kind of ballast than can run them also required a specific line voltage. But to be honest, even with some LED retrofits than run on existing T12/T8 ballasts, the installer is supposed to verify the ballast inside is on the list of approved ballasts. In practice that probably never gets done.

@WorldwideHIDCollectorUSA
Why in the world would there be an OCV limit on Super Aces? That's ridiculous, though you could use a pulse-start ballast without an ignitor. They usually are in the 240V class of OCVs. I would love to know the technical reason behind this restriction.