I think the twin arcs are an interesting bulb and will be something to look into in the future, but they dont work for his needs at the moment as they need a pulse start ballast, (read comments after article...author spoke to ALS about what ballast is needed and was told pulse start), and he has an HQI ballast.
From what I gather, the bulbs will alternate which arc lights up, but there is still the cooling period to think about. The ballast prevents bulbs from lighting back up immediately in order to give bulbs a chance to cool down. When switching from one arc to the other, it still does this. The article states "Although a typical lamp would take 15 or more minutes to cool down and fire again, the off-duty arc tube only warms up a little bit by comparison and the Twinarc is ready to fire up again in a couple minutes."
However, in my experiance, its the ballast that decides when to fire up again, not the bulb. I've tested this buy firing up both HQI and Electronic ballasts with one reflector and bulb. Shut it down after a few minutes, and then plugged in a different reflector and bulb that was cold and had not been running. It still took 15 minutes before the new "cold" bulb and reflector would light. Just to be fair, the ballasts I was doing this with were my Bluewave & which was manufactured in 2006, and a pair of Bluewave 4's (IceCap's in a blue box) which I bought back in 2004. So its entirely possible that the newer ballasts will sense the temp of the bulb and that will determine the time delay on firing...however, I kinda doubt that since it would increase the cost of the ballast and I havent seen them increase all that much in the last couple of years.
Secondly, you either need one of their specially made reflectors or you need to fiddle with a full size Lumen Arc reflector to situate the bulb properly to get the full benefit of the twin arc bulb.
Having said all of that, I really like the concept of the two bulbs in one idea and really, really like the idea of double the bulb for the price of one. When you think about it, if you decide to run a bulb normally, (IE one "On" time, and one "Off" time per day), then you are doubling your bulb life. That in and of itself is worth the price of buying new reflectors to accomodate the longer bulbs...you'd pretty much save the cost of the reflectors after the first year when you didnt need to replace your bulbs. By the second time you replaced your bulbs, (4 years later) you'd be ahead of the game...
I'm going to wait a bit and see how these shake out, but I can see some real promise with the Twin Arc's...
Nick
