[geeks] Metal Halide Bulbs

[Bjorn Ramqvist]

Aaron Finley wrote:

> Or, I wonder what nifty things I could rig up. I know I'd need a
> ballast. I grow bonsai, so this could be beneficial. Room lighting?
> These bulbs seems to insist on their own level of not being safe,
> however, as the warning label states that they might explode and there
> are other bulbs on the market that would not. Could one make their own
> reflector, housing, or would that be an invitiation for disaster?

I use metal halide lights for my coral reef aquarium with great success, 
although there are many areas where you can benefit from HID instead of 
the usual halogen lightning.
Areas where you want to light up in the extreme (think football 
stadiums) they are always using high pressure sodium or metal halide 
lightning, because standard halogen spots would be otherwise 
inefficient. A 75W HID bulb would be about the same amount of light as a 
500W standard halogen light and with less heat too.

HID lights *can* explode if they go too warm inside the fixture, so in 
the case of double-fitted lights they are always enclosed behind a 
protective glass in front and also to filter out the hazardous UV rays.

To light up a HID light you need, of course, a ballast but you also need 
an ignitor which is a seperate module (depending on the type of ballast 
used) which connects between the ballast and lamp. There are several 
versions of this igniting procedure depending on the type of lamp, but 
luckily here in europe they seem to standardize things quite a bit.

/Bjorn