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Pros/Cons of reflector built into bulb?

T

TKM

Jan 1, 1970
0
Michael Shaffer said:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7732986576

I was just wondering, do these have a shorter life span, since I assume
they get hotter? Are there any other downsides? I haven't seen many like
this for sale.

The lamp referenced appears to be an HID type -- probably metal halide or
mercury. Heat would not affect the life of such a lamp significantly.

Whomever is selling the lamp apparently does not know much about it since
there is no description. You should figure out what kind of lamp it is
since it may need a unique ballast type for proper operation.

Terry McGowan
 
V

Victor Roberts

Jan 1, 1970
0
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7732986576

I was just wondering, do these have a shorter life span, since I assume
they get hotter? Are there any other downsides? I haven't seen many like
this for sale.

I can't find these in a short search of the Philips Lighting
on-line catalog and there are no similar lamps listed in the
Philips Lighting print catalog.

If we take the eBay listing at face value, these lamps are
optimized for higher than standard efficacy (higher than
standard output at the same power). This requires that the
arc tube be operated at higher than standard temperature (by
making it smaller) and that higher temperature will reduce
the arc tube life - again compared to standard lamps.

However, the data supplied is a bit suspicious. A standard
Philips 400-watt M59 (standard start) metal halide lamp
produces 36,000 to 40,000 initial lumens. A Philips 400-watt
pulse start quartz metal halide lamps would produce 44,000
initial lumens. So, the claim of 60,000 lumens is
"interesting" to start with. Then you need to factor in that
reflectors are not 100% efficient, so reflector lamps
produce less light than a bare lamp of the same technology
and power. Raising the arc tube temperature can increase the
efficacy - but this is too large an increase in efficacy,
especially for the claimed reduction in life.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
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V

Victor Roberts

Jan 1, 1970
0
The lamp referenced appears to be an HID type -- probably metal halide or
mercury. Heat would not affect the life of such a lamp significantly.

Whomever is selling the lamp apparently does not know much about it since
there is no description. You should figure out what kind of lamp it is
since it may need a unique ballast type for proper operation.

The description says metal halide and the ballast is
identified as an M59.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
 
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