250W MH Lamp Heat (test)

[rbredding]

I took a 250W MH Lamp, ballast, holder, etc and set it up on a piece of plywood.. the Mogul base holder that I used held the lamp approximately 1.75" off the plywood..

I plugged in the ballast and let the lamp run...

about an hour later, I felt the plywood near and under the lamp, it was too hot to touch with my hand..

I then placed a spider type reflector under the lamp and let the lamp run...

about 45 minutes later, I removed the reflector and felt the plywood, it was not only comfortable to the touch, there was no apparent difference between the temperature of the plywood under the lamp, vs. the edge of the plywood that wasn't under the reflector..


I knew that the reflectors will reflect both heat and light, but I guess I expected them to at least be warmer than they actually were, or transfer more of the heat to the plywood (which of course serves as the top of a canopy)

I wasn't trying to be very scientific or test it in a strictly controlled environment, I just wanted an idea about how hot/cold it would get..

Has anyone else played with their setup and found things that either reduce the heat or add to the heat of a lamp?
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[hfleming]

I have a very similar setup in my canopy. One thing I did different was to add small spacers between the reflector and the wood. This allowed a small air gap to exist and even less heat was transferred to the wood.

 

[acroholic]

Spiderlight reflectors come with spacers to place between the reflector and the canopy. The manufacturer stresses that placement of these is essential for proper operation.

I have hanging Lumenbrite Mini pendant lights, and they are the reflector covered with a thin outer painted metal, and my 400 watt ones are only warm to the touch on the outside.

That spacing is needed, otherwise there'd be canopy fires all over the place and these manufacturers would be getting sued.
Dave

 

[rbredding]

Acroholic;390137 wrote: That spacing is needed, otherwise there'd be canopy fires all over the place and these manufacturers would be getting sued.
Dave

that's what I'm saying.. (and the reason for testing this in the first place..)

just the reflector flat against the wood and it didn't get so hot that I couldn't touch it..

I would have been worried about putting the lamp so close to the wood (and the reflector so close to the wood) if I had not tested it and found that it didn't get any where near hot enough to flash flame the wood...

 

[acroholic]

I just took down a homemade pine fixture that was hanging over a 265 gallon planted tank, and I had three spiderlight reflectors with 250 watt SE halides sitting against pine with the spacers installed, and this fixture ran 9 hours a day for three years straight, and when I took it down and removed everything, the wood where the reflectors got the hottest looked perfect. No browning or blackening.

 

[rbredding]

After my little test, I'd have to attribute that to the reflector itself, not necessarily the spacers...

 

[acroholic]

Rbredding;390288 wrote: After my little test, I'd have to attribute that to the reflector itself, not necessarily the spacers...

I wouldn't attribute it to the reflector or the spacers, but the airspace between the reflector and the wood. Same principle with my LB pendants. The outer metal only gets warm because there is an inner airspace betwen the two pieces of metal.

 

[rbredding]

that is the same situation as my reflector (no spacers) against the wood..

 

[acroholic]

Cool!:shades:

 

[weaglereefer]

I also have no spacers with my spiderlight reflectors (didn't know they came with them). Wood inside the canopy is barely warm to the touch, on outside there is no difference in the temp (measured with automotive infrared thermometer).

 

[acroholic]

Rbredding;390329 wrote: that is the same situation as my reflector (no spacers) against the wood..

You know I just took a look at your pictures, and I have been basing my comments on the spiderlight reflectors I had. Yours are different. Mine were long enough so that the Mogul base mounting bracket attached thru the spiderlight reflector. Mine were a part of a complete retrofit from Marine Depot, and came with the spacers I was referencing. Mine must be a different version. Sorry for any confusion r/t my comments.

Here is a link to mine: note the multiple ventilation slits cut into the part of the reflector that faces the wood.