Does anyone know of a good site to learn about high pressure sodium and metal halide lighting? I am especially curious about the function of the capacitor and why on the transformer it states the cap is "optional"
Thanks, Brian

Hey Brian,
Go to ballast school--http://www.advancetransformer.com/university/default.asp

Thanks VT that was a good tip. I am already educated!
Brian

Did you print your certificate? I give my guys twenty dollars out of the recycle fund when they complete advance's ballast training or Lightolier's lessons in lighting.

Brian;

Did the Advance University help out?
If not, poke around here a bit, and you'll find many discussions of the HID nature!

BTW: Normally, a Capacitor is used to improve Power Factor from Nominal (50%) to High (±90%). This is the "Option" of the High Pressure Sodium "55 Volt Lamp" family, as are a few other low Wattage HIDs.

There are other uses of the Capacitor - such as with the High Reactance Autotransformers - where the Cap is driven on the Input side of Ballast, and with CWA's, it's a series element to the Reactor section. With Regulated Lag Ballasts, there's a seperate Capacitor Secondary Winding.
All these setups do not specify the Cap as "Optional".

Scott35

Thanks for the link, I just got my certificate. Going to do the Lightolier's next. Interesting stuff

Did you guys get the answers you were looking for at the linked sites?

I have been to these sites and, while the information is rather nice, there's really not a lot of technical references - such as the reasoning for "Optional Capacitor for HPS Ballast", like which ones do and do not have "Optional" capacitors, along with the results of not using a capacitor on Ballasts which incorporate one in the Lamp circuitry, or on the Secondary side, or in the Primary side (not listed as "Optional Use" of caps.).

Just curious...

Scott35

p.s. how about an on-line HID quiz???
would be fun!

Scott,
I got all my questions answered. The ballast university is real nice, you can refer back to it anytime. Thanks for this site.
Brian