Hi everyone! So today I purchased 4 new old stock general electric F60T12 Slimline tubes! I am quite excited abotu themm, despite not having any fixture to use them in currently. They have FA8 pins, so a single large pin on each side. I have a few ideas how I could make my own sockets for them, so this is not really a problem. I am more curious about their current and voltage ratings and such, so I can choose a suitable ballast to run them. If anyone has any input regarding their operating voltage and current, I would be really happy I have looked for datasheets, but unfortunately cannot find any. I have some ballasts I Can experiment with, so in the worst case scenario, I can play around and measure the current and voltage until I get the desired lamp power. I'm assuming these tubes have some sort of ignition strip internally, since they are single pinned. My plans for these mainly, is me thinking something along the lines of making my own fixture for them, I do have both the equipment and knowledge how to make sheet metal pieces become the shape of a industrial light fixture

Is 60 the power (in watts) or the length (in inches)? If it is the length, then I need the wattage and I can let you know (or vice versa).

Or you could just look yourself, whatever:
https://docs.google.com/spreadsheets/d/e/2PACX-1vRyPSC_n1dhry8yQsygp1qXoub7YLaBoZcg-yZD2EY6nsw-XBSPN3IN666SN__ljA/pubhtml

60 is the length in inches. The lamp wattage is 50 watts.

That’s an incredibly nice spreadsheet you’ve made, thank you! That will be of great help.

Well it appears that particular tube size isn't on the spreadsheet yet. It is a T12 tube, so around ~.43A, and if I were to guess around 125V across the tube (in between 48" ~100V and 72" ~150V). The best choice would be to use a 56W 60" T8 HO (I don't actually know what they are called) instant start ballast. That being said, I haven’t ever seen or heard of one of those being made, so you might have to make do with a 40W 48” T12 instant start ballast, which will underdrive the tube slightly. According to Fulham, a Fulham WH4 can light a 60” T12 tube, but those are notorious for underdriving.

If you don’t want to underdrive the tube, you could use a 57W 72” T12 ballast with some sort of limiting device to decrease the power down to 50W, but that sounds like a lot of work.

If you ever do find the actual specs, do let me know so I can put it on the sheet.

I had a look at your spreadsheet and realised the same hehe. Very well made though! I’m going to save that so I can refer to it when I need

I may have some more tube data to help you add there too on European tubes since I collect a lot of those too!

It is indeed a really rare size and that’s what made me interested in them, I’ve never seen F60T12 before

I think I’ll give a European 36/40W, or 58W ballast with a series limiting of some sort a shot. I suspect the 40W will work fine We have 230 volt mains so I am hoping the tube will successfully strike even without an auto transformer ballast. If I’m not entirely mistaken these tubes have a coating on the inner glass that helps them strike capacitvely. These don’t have filaments that can be heated since they are single pin tubes, so capacitive start is the only way

I’ll have to  experiment and try different things out, and I’ll definitely be sure to report my findings! I did manage to find FA8 sockets for sale, so I bought some but they won’t arrive until the 16th June. The tubes should arrive next week, maybe on Tuesday. I found them on eBay too, and I probably paid way more than they were actually worth, but they’re quite rare and they are 50’s vintage I think, so I’m  mostly okay with that. I’m excited to have a play around and build a fixture for them

I think I’ll have a look at purchasing some sheet metal this weekend! With my equipment I won’t be able to make a 5 foot fixture in one piece, I’ll have to make it in at least 2 pieces and maybe weld them together in the middle.

I’m excited

Oh my! I forgot that you live in Sweden. For some reason I just assume everyone is American lol. That changes plans a bit. If it can indeed strike on its own at 230V, that would be excellent.

Definitely do let me know if you have more specs, most of the fluorescent tubes on the spreadsheet are American, so it isn’t particularly diverse.

You could get a capacitor of just the right value to put in series with a 58W ballast to limit the current, but finding the right capacitance would be a pain, and it might actually shorten lamp life due to capacitive ballasting, so I wouldn’t bother. You could also wind another small choke to put in series with the 58W ballast to limit current, but that would take even longer. While a 40W ballast will underdrive the tube, I don’t think it would have any significant effect on the lamp life, so I personally would go with that (just my opinion).

Fa8 sockets in the US are pretty common, I am surprised to hear that they are so hard to get over there, though they are vintage so that might play a role.

If you can do sheet metal work, you can do a lot with regards to lighting! I wish you luck building this fixture, and I look forward to seeing it in action!

The sockets should be easily obtainable off eBay
A 2xF32T8 electronic instant-start ballast wired for overdrive in a single lamp will run them at something close to the correct current. (the multi-voltage 120-277v 50/60hz models are very common)

Only issue would be cost of shipping

I'm pretty sure you can still buy electronic slimline ballasts new, most of them are rated for something like 4-8ft lamps.

I'm pretty sure slimline lamps just use brute force high voltage to start without any starting electrodes or conductive coatings, here's a Universal 875-L-TC-P cold temp f60 ballast that lists the open circuit voltage as 525v. https://www.ebay.com/itm/234280436335

A 240-480v transformer and a pair of 1x20w ballasts in series would probably work, or maybe a 35w mh ballast and a sox ignitor?

Most american ballasts have the capacitor in series with the lamp(s) and it works fine as long as they use decent quality capacitors and there's enough inductance in the circuit to limit the current spikes.

God knows those weird American fluorescent types... But I bet this is 40W/60T12/IS lamp. Thanks Alex for a link to a free ANSI C78.81-2014.

40-Watt, 60-Inch T12, Mogul Bipin,
Instant-Start Fluorescent Lamp
40W/60T12/IS
40 watts
60 in (1500mm)
T12 (T38)
G20, Mogul bipin
Instant start


It seems to be relatively close to world-standard 4ft T12 (103V 0.43A) at 0.425A 107V

Ballast requirements are 430V OCV 0.425A 930 Ohm impedance. Direct emulation of this looks like 1:2 step-up transformer from 230V and two 36W + 18W single tube 230V chokes in series approximately.

ANSI says:
Lamp starting requirements
Voltage at 50°F (10°C) and above, (Vrms) min 385

So the lamp won't start directly from 230V mains. Some ideas -

May be just a 36/40W choke from 230V will be OK with a starter parallel to the tube. May be not. SOX ignitor will probably work.

European electronic 36W instant start ballast with bi-pin connection - yep these DO exist, though not everyday items. I have seen one from Tridonic recently. The regular 36W electronic may also work. What to do with 4 wire connection? My bet is most versions of electronic ballast circuits will tolerate tying two terminals at each lamp end together without giving out smoke. You take the risk. There is a heap of scrap 36W electronic ballasts everywhere today, so not much tears.

36W electronic ballasts will sure underdrive 40W tube at about 32W real.





 

@RRK
Tigerelectronics said that the wattage was 50W, not 40W, so this might not be the right data. He also said that this has a conductive coating on the tube, so I think it could be a different tube. I might be wrong though...

I'm pretty sure you can still buy electronic slimline ballasts new, most of them are rated for something like 4-8ft lamps.

Yep.. I forgot about those when I made my earlier post. They do exist (both T8 & T12 versions) but they're getting somewhat hard to find(especially the T12 ver)

@RRK
Tigerelectronics said that the wattage was 50W, not 40W, so this might not be the right data. He also said that this has a conductive coating on the tube, so I think it could be a different tube. I might be wrong though...

Yep thats a different tube. Infact it looks like its a retrofit tube for a F40T17-IS because it states "mogul bipin" (F40T17-IS which is electrically equivalent to a F48T12 slimline, and very close to that of a standard F40T12)

The F60T12 slimline is 50w & current of 425ma/430ma ... If a standard 5' 50w bipin (ie: F50T12 ) lamp existed that'd be the closest (I always wondered why they didn't make such. ? .lol. )

That's weird.


I was not able to download 2001 version of ANSI C78.81, but all later versions list *only one* 60 inch instant-start T12 tube which is 40(42)W version @425mA 107V

No 50W T12 slimline at all in ANSI standard. Already got obsolete and was removed?

Lots of interesting stuff- thank you all )))

It’s definitely going to be interesting to see how these tubes behave. I unfortunately found out that they’re going to be delayed in shipment, so I won’t have them until the end of next week, but that’s okay. Perhaps the sockets can make it here in a similar time so I can pick up both. It also gives me some more time to find ballasts.

But in the meantime I’ve been reading all of you guys posts and it’s been of great help for me to think about how I’m going to get these to strike up reliably. You guys said, I too doubt they will actually strike reliably on 230 volt mains. Since they have no heaters, a high voltage pulse will most likely be needed. Or a high enough OCV to make the gasses break down and  strike the tube.

Using normal 36/40W ballasts rated at 0.43A is probably going to be the best bet I have at running these as close as possible to their rated power and current. I was thinking about connecting a starter literally across the output from the ballast, to short it on purpose and then create a high voltage pulse as the starter releases. Theoretically this should work, I don’t know how long the starter will last doing this though, but theoretically I don’t think the lifespan will be affected too much since heater filaments are typically just a few ohms. So I think that method might work, this unfortunately means I’ll have to find some recessed starter sockets and drill more holes than I had planned to into the fixture, but if I have to do that, then I’ll have no choice I suppose.

Another thing that came to mind was running the fixture at 400 volts, which we have across phases here. And I’ve got free access to 3 phase power, so I could do that too. At that voltage the tubes should self strike without issue I’m guessing. And since this is meant to be an industrial light fixture, 400 volts isn’t actually that bad of an idea. 3 phase lighting installations are very common, although usually connected between one of the lines and neutral, and the fixtures spread out between the phases. The only question then would be how to ballast it, since all normal ballasts are 230 volt rated. Running them at 400 would mean the current would be at least double on the output, probably more as the core saturates.

a current limiting Capacitor in series with the ballast is one thing I thought about aswell, although I am aware of how bad capacitive ballasting is. I might still give it a shot though and have a poke around with my oscilloscope and stuff to see if the sinewave becomes too horribly distorted and hurts the tube in the long run. I don’t like having capacitors on mains voltage because they always go open circuit or start leaking or blow up, but I feel like I don’t have a choice in this case…


Of course the third option, is to purchase a new old stock American 3-lamp magnetic auto transformer
Ballast, like these tubes were originally designed to be used for. The only problem is the cost of the shipping, it’s ridiculous having to pay double what the item is worth in shipping…  dealing with a 120 volt ballast would probably be easier since I have free accesss to transformers. The only problem with an American ballast over here is because of our lower mains frequency of 50hz, the ballast will output more current than it was designed for and it may also overheat. A 277 volt
American ballast might work fine on 50hz and 230-240 volt mains since the voltage is lower, as a result slightly less losses will occur in the ballast and the output current will probably be close to what it would be at 60hz, because of how reactance works and everything. I mess around a lot with vacuum tube audio amplifiers, so I’ve experimented a lot with transformers and inductors.

Although, my little day-brite 2x20W fixture, American, with a lovely old GE ballast has been running for years on 120 volts at 50 hz from a step down transformer
Without overheating or damaging the tubes, so it may work or it may not work. Depends on how much iron is inside the ballast, I suppose


But I’ll definitely make sure to update you all about what my findings are about ballasting and how to get these tubes to strike reliably. I may even make a YouTube video. It’s far easier to explain and show things in a video

Oh yes, did you all see my other post here where I show the build process of the light fixture I’m making to run these in?

eah the standards are ab it tricky regarding that. There are some lamps i did not expect o find in these modern standards like the PG tubes. However then there are tubes that never were standardised like the 33W T12 tube are some of the HO/VHO instant start tubes. However that is not limited to the ANSI standard. THE IEC standards for MH Lamps list Philips cosmopolis lamps but does not list any MH lamps above 400W...

Reagrding that tube i think it is fairly similar to the F60T17 instant start lamp. The power most likely increased as these lamps are run at constant current and due to the small diameter the lamp voltage increased