I've done that! now what about reflectors?
I've done that! now what about reflectors?
Someone asked how do you tell electronic from Magnetic?
A: Simple. If it weighs about 20 pounds or more it's Magnetic. (you can also read the label)
I used to run a 36" VHO (T12, Actinic) on a balast intended for an 8 foot T12 bulb (80 W). The bulb was rated for 90W, but I'd have to have shelled out 4-5 times as much for a VHO ballast, while I had the other one lying around. (the prices have come down a little bit on VHOs in the last 3 years, but still...over priced!)
Flourescent lighting is really not that complicated, even less so with Instant start balasts. They have all these numbers and rating and stuff, but it just boils down to voltage and wattage
A flourescent light is just an electrical arc surrounded by some phosphors (coating the glass) that convert the UV emited from the arc into more desirable wavelenghts.
To get the arc started you need a high voltage (about 100 V per foot of tube) (older ones had a heater in the ends to warm up some ions so the starting voltage could be lower) after the arc is started, the ballast just limits the current flowing through the arc to the specified power level (that's all a balast does).
Lamps are constructed so there is an appropriate desity of mercury vapor compared to the size of the tube and the type of phosphors, so you can't get too crazy... for example you could try pumping a few hundred watts through a 40W tube, but it will loose some efficiency, and will probably get really hot and shatter, but it would sure be bright for a little while. The opposite is true, you can buy a VHO bulb, and run it a lower power, but I don't know why you would. I'm not going to say that anything is "safe" even following the ratings exactly, but there is room to play here, and it can be worthwhile in terms of savings on hardware, and overall efficiency, if you know what you are doing.
I am interested in Making a better reflector. "reefburnbaby" mentioned that an optimal specular reflector is shaped like an "M" can somebody post a picture of a cross section of a good design, that could be made from cheap aluminum flashing for DIYers. It seems like 3 lengthwise folds would make an M, and be really simple, but what kind of angles? the "computer designed commercial ones I've seen just have an arc or have many more folds than an "M"...