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Jeff Wisnia[_9_] Jeff Wisnia[_9_] is offline
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Default Do Thermal Fuses Die of old Age?



wrote:
On Monday, March 14, 2016 at 12:56:59 PM UTC-4, Jeff Wisnia wrote:
Over the years I've had to replace maybe a half dozen thermal fuses
which appear to have failed without ever being heated beyond their rated
temperatures.

Most recently a small electric space heater used in our office under my
desk stopped working because its thermal fuse had opened. The fuse was a
MICROTEMP G4A0 121 degree C unit, and I'm pretty sure that nothing had
blocked air passage through the heater and caused its internal
temperature to rise enough to open the thermal fuss.

Jeff


They most certainly do die of old age. As do regular current-limited fuses. If ever one wants some very dry amusement, bring a glass fuse close to its current limit and watch the filament dance inside the glass.

Peter Wieck
Melrose Park, PA

That may be what's going on inside the 2Amp 3AG fast blow fuses I
installed in the four metal bodied table lamps I'd added "touch dimmers" to.

When the 150 watt bulbs I use in those lamps burned out the "thermal
arc" would often send the touch dimmers to the graveyard, so I added
fuse holders and fuses to the lamps. Those fuses protect the touch
dimmers, even though I have to replace a 15 cent fuse almost every time
a bulb burns out.

It's still worth having touch dimmers in the lamps because SWMBO and I
don't have to stick our arms up under the lamp shade and fumble around
for the rotary switch on the socket.

Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.