Found this nice 450w Duro-Test Fluomeric SBMV at Restore. I'm guessing this was used to retrofit incandescent highbays back in the day. Anyway I didn't test it yet as my step up transformer only goes up to 500w (450w is a bit close to the limit for me).
Yeah, it's a 230v model but I guess I could test it on 240v too but the lifetime might be shortened. I need to find a 1kW step up transformer or better, a 15A 0-240v variac to run it.
one thing I'm wondering though, is why is this a 230V lamp and not 130V, since MV lamps have an OCV of 130, right? does the filament also reduce the voltage from 320 to 130 or is there some other sort of voltage limiter in there?
IIRC, with discharge lamps you need around double the arc voltage to start them reliably. I believe this is because there is also a voltage drop at the ballast. Low watt HPS and small preheat lamps have a arc voltage of 55v and 60v which corresponds to a 120v OCV at the ballast.
Most MV lamps need 130v OCV so the minimum OCV you need at is around 200-220v to start them reliably. 120v SBMV lamps are specially designed, they have preheating filaments at each end of the arctube to warmup the lamp during starting which reduces the starting voltage.
ahh so is that why 240V MV ballasts are simple chokes and 100V HPS 240V ballasts are simple chokes compared to other voltages that have more complex ballasts?
Yep, 277v PSMH ballasts are also chokes too. In theory 277v F40T12 ballasts could be choke ballasts too (yay preheat F40) but I think all of them are rapid start.
Oh and here's something fun, you can actually run two 35w HPS lamps using only one 70w MH ballast.
Very nice find! These are somewhat rare. As for the voltage you could run it off the clothes dryer or A/C circuit. I have even lit a 450w 230v SBMV on a 400w MV ballast since the OCV is 240v but not sure if its a good idea, although it did light and reached full brightness.
Thanks! Dave. Don't have any 400w MV ballasts to run this on though. I would use a 400w MH ballast but I think the higher OCV won't be good for the lamp.
i wood not recomend using a HID ballast as a step up tranny at all as while the OCV is 240V under load it drops but if ur ballast is multi tap u can use the unused 240V tap to power ur lamp up
Wait, if you have a multi tap ballast and use it on 120V the 240V wire, though unused, still has 240V at it? so a multi tap ballast can be used as a transformer?
Apparently so...I've been told that too. Just don't go over what the ballast is rated for (450w might be a bit dicey for a 400w ballast, etc.) It makes perfect sense to me though since they have to step up the voltage anyway...
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Yeah, it's a 230v model but I guess I could test it on 240v too but the lifetime might be shortened. I need to find a 1kW step up transformer or better, a 15A 0-240v variac to run it.
Most MV lamps need 130v OCV so the minimum OCV you need at is around 200-220v to start them reliably. 120v SBMV lamps are specially designed, they have preheating filaments at each end of the arctube to warmup the lamp during starting which reduces the starting voltage.
Oh and here's something fun, you can actually run two 35w HPS lamps using only one 70w MH ballast.
@joe347V, you are correct I would not recommend a MH ballast they are 280V OCV.