Explain these lamps please...

[Robocop]

Knowing very little about metal halide lamps I hope these qualify to be in the incandescent forum....I think they are classified as incandescent and I am curious about this style lamp.

A friend gave me these to play around with simply because I was so facinated with them after seeing how he had his home aquarium set up. I know they need a ballast of some sort and are more suited to aquarium use however they are still facinating to me.

Ok these lights were almost crystal white when powered up and made an incredible amount of light. I know nothing of color ratings however both these lamps say 20000K and I assume this has to do with the color....right?

I am not really interested in using them but more so of learning just how they work as well as how they are so white for incandescents? Ok the first one is huge and it is labeled... E39 Base-T Shape-400W-20000K and the closest pic I could find on line is this http://www.marinedepot.com/ps_ViewItem~idProduct~MB8819~tab~2.html

The second one is smaller and labeled...R7S-150W-20000K and looks very close to this http://www.homedeliverypetsupply.com/prod_details.php?pcode=ACU02073&sc=3

Are these Metal Halide all known for being very white tint or is it just the 20000K ones my friend uses? Also how small can you find metal halide lamps and does anyone know of any handheld applications such as portable lighting?

I am not sure why they facinated me so much but again I was really impressed with these two lamps....I tried searching but quickly became dizzy with all of the tech stuff and numbers I know nothing about. So can someone explain in a nutshell what these are mainly used for and the pros and cons of their use?....Man these things were simply blazing white and made his entire aquarium look beautiful. Maybe it was the other lights or even the water but they looked to be the whitest incans I have seen.

Thanks for any help on this.....

 

[Aussie Cheese]

they are bright due to the high quantum yield, but have low cri, depending on the mixture if gases within the bulb

 

[broadgage]

It sounds as though these are discharge lamps, not incandescent.
(there are many types of discharge lamps, of which metal halide are one)

Color temperatures normally range from about 3000K up to about 6000K for general purpose lighting.
The much higher colour temperature of 20,000K is normally used for lighting aqauriums and the like as it is said to benifit plant life.

 

[yellow]

Possibly You can read more info, when looking into the "spotlights and HID Lights" sub-forum - for getting infos on HID lamps

but they looked to be the whitest incans I have seen.

"incans" are also called "hotwires" because they have a wire that emits the light.
HID / metal halide / "Xenon" lamps produce a steady "flash" (an arc) that makes the light, there is no wire --> no incan.

the ballast has 2 functions:
1st offer the high voltage to get the initial sparks (has to pass a few mm of space) and
2nd to provide the lower voltage when the arc is steady (thats usually around 60 V, mostly AC)

When powering them up, the show is simply outstanding

 

[Robocop]

Thanks for the help yellow and maybe this will be a better suited section for this...I moved it from the incandescent section as I had no idea these were not true incandescent lamps.

If I remember correct my friend had one of the larger lamps tucked under a canopy above his aquarium while the smaller one was closer to the top of the water. The smaller one was impossible to look directly at even from a few feet away. I am not sure which one was making the very white tint however the entire aquarium had a crystal white and very slightly blue color. The output was amazing to me and the insides of these lamps just looked very complicated.

Thanks for the information again and maybe I can find a use for these someday.