Mannnn.... I still really wanna properly light this lamp... WOuld I be able to put a resistor of some sort on a 175W ballast to reduce it to proper spec? or would that ruin the ballast? Or... is there some way to make an F40T12 ballast not under drive the lamp?? what If I used an F32T8 electronic ballast I recently obtained? would that overdrive or underdrive it? if it overdrives could I put a resistor to reduce the current a bit?
Forget the F32T8, it is too far away (too low current, the lamp has too low voltage for the F32T8 ballast, the MV lamp may not like the HF supply)
Two F40T12 ballasts of a bit lower ballast factor (0.7..0.8 or so) in parallel (those two outputs should really work in phase and the ballast should not be designed for series pairs) should work.
Using the 175W ballast is tricky:
In theory it may work, but in the real life you will face some design problems.
The only reasonable way is to use the "175W" ballast just as a step up transformer and add the ballasting impedance behind.
First conditin for success is, the ballast is capable to operate open load without any significant input current. If this condition is not met, you will likely face problems with ballast overheating. So then assume for now it is not dissipating anything significant. The HPF HX type will most likely need the PF capacitor disconnected (you won't need it in the 75W MV setup). When trying this, youwill have to measure the OCV, you need it later.
The added ballasting impedance could be a capacitor (in place of the original one if it is the case of CWA), but it would have to be of significantly lower value. Because of the leakage inductance of the transformer part, you would have to determine the value empirically, the good starting value would be half of the "175W" capacitor in case of CWA or 1/(3*2*pi*60*sqrt(OCV^2-110^2)/1.6) in case of a HX type.
Or you may use a resistor (a 240V incandescent,...) as the ballasting impedance, the resistance then should be about (OCV-115)/0.75. Look on the
incandescent chart to determine how the incandescent resistance will change with the voltage across the incandescent (about the OCV-110) compare to the incandescent rating.
Then try to assemble the setup and empirically adjust the impedance (capacitor value and/or incandescent total power rating) so you get the correct 0.75A through the MV arc (or something close to that).
