I have purchased a new 400w HPS ballast for my new GE M-250A2. I wired it up and i on accident put a 250W HPS lamp in it and it was a cool white color not a red-orange color. Does anyone know why this happened?

Thanks

This should answer your question   By the way "SON" is an European term for HPS so same thing, hope that helps

I'd like to throw in a couple more details. I once ran a 50w HPS lamp on a 1kw mercury ballast. The effects were dangerous but impressive, the color of the light turned white, then blue, then green and the arc tube exploded, coating the inside of the outer glass with silvery sodium. However it nicked the glass on the side (nearly took the outher bulb) so air got in and after a few hours the silver coating disappeared. Call me crazy if ya like :-P

thats amazing dave!!!

Dave! that's REALLY crazy, but I have something worse! I microwaved a spiral CFL one time, just enough to mess up the ballast a little bit, I took it outside, powered it up, and the ballast caught fire!

These experiments would make great YouTube videos. 

Someday I know someone's going to replace an oven lamp with a CFL. Would you like mercury & melted plastic in your pizza? 

Wow...I didn't think a M250A2 was designed for a 400w lamp!

Arcblue: Another recipe related to lighting! We should make a recipe book with all our recipes, such as:

- Geoff's chips

- Jace's roasted ballast

- And much more!

We can add your PM pizza (PM for Plastic-Mercury not for Personal Message  )

Wouldn't overdriving any lamp do damage to the ballast by overheating it?

probably im not really sure,but any time you use the wrong lamp or the wrong ballast chances are high you could cause damage to the lamp,ballast or both.

Wouldn't overdriving any lamp do damage to the ballast by overheating it?

Depend on ballast concept and what the overdriven lamp does.
MV will not do anything to the ballast, as it's voltage is stable and the same for nearly all wattages, so the ballast would "think" it has correct lamp in it. Of course, the lamp will explode soon.

SON (HPS - for Americans :-)) would most likely cycle - as overheated tube rises the sodium pressure, so discharge voltage, till it exceed (with restrike spikes) the ballast OCV (except low voltage run on high voltage ballast - e.g. US HPS70W run on HPS150W ballast). The ignitor will quickly eat-up it's lifetime (as it's designed for only few pulses per start).

MH: Unsaturated vapor concept (some QMH) behave same as MV, saturated vapor concept (all CMH, some QMH) behave like HPS.