Date: Wed, 14 Jan 2015 14:05:16 -0500
From: Hans Hammarquist via TowerTalk <towertalk@contesting.com>
To: towertalk@contesting.com
Subject: [TowerTalk] Fwd: Fwd: Now THIS is a tower climb!
It's a well know fact that the life span of incandescent light bulbs increases
with lower operating voltage. If I remember it right the lifespan increases by
7 times with a 10% decrease in voltage. I guess a 240V bulb working on 120V
would outlast the life of the radio station. Light efficiency (power in - light
out) is not that good though.
Hans - N2JFS
## I installed 130 vac rated flood lamps for my motion detector lights
outdoors. 5 pairs of them, 10 in total. They are 100 w rated. When run on
120 vac, they are not as bright, abt the same as a 75 w bulb.
I installed them back in 1998. They go on and off all night long if windy
outside. They are just starting to burn out now, 2 of em.... 17 years later.
If a thermistor was used, they would never burn out.
They still don’t make a LED replacement for outdoor floodlamps...yet. The
indoor leds are supposed to be good for 25k hrs.
## on a tower light setup, if 130 v rated bulbs used..and run on 120 vac....
and thermistor used to ramp the V up.... or a variac, they would never burn
out. Or use 120 vac rated bulbs..and use a variac to slowly
bring em up to 100-110 volts. Tower’s need redundant bulbs..or redundant leds.
## they already make heavy duty, long lasting bulbs for hard to reach places,
been around for 35 yrs or more. They contain a real heavy duty filament.
Since the cold resistance is one tenth the hot resistance, the bulbs always
burn out upon turn on. A variac, or simple dimmer, or thermistor would solve
that problem..plus lower the V 10%.
Jim VE7RF
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