Calling all Electricians!MH voltage, amperage between differ

[Larry1]

What goes up as a metal halide bulbs wattage goes up? Say between a 175 and a 250W bulb. The amperage drawn by the bulb, the voltage supplied to it by the ballast, or both?

I mean the parameters at the bulb not at the current source for the ballast.

If there is a standard voltage at the bulb we could use a 175W bulb with a 400W ballast. If the voltage differs then we can't.

Larry

 

[AnotherGoldenTeapot]

Current is all that changes.

All that ballasts do is limit current.

Most designs only have a single coil - they are not transfomers.

If you run a 175W bulb on a 400W ballast then the bulb will be supplied with the current required to run a 400W bulb.

So, you can't run a 175W bulb on a 400W ballast (well you can run it - but the bulb won't last very long).

 

[Larry1]

Thanks. That was informative. In many light systems the bulb limits current, but it seems the current is limited by the ballast in MH systems then.

Thats too bad. I was hopeing it was like florescent where you could use the higher wattage balast with the lower wattage bulb and be ready for higher wattage bulbs when You needed them without switching the ballast.

Thanks again for Your input:
Larry

 

[AnotherGoldenTeapot]

Here's a good "more than you want to know" site on the subject:

http://www.misty.com/people/don/dschtech.html#n

 

[Anonymous]

FWIW Here is another "More than you wanted to know about HID lights" site web page