Re: Insteon Observations

[Victor Roberts <xxx@xxxxxxxxxxxxxxxxxxxxx>]

On Sun, 17 Dec 2006 14:49:12 -0600, Bud--
<remove.BudNews@xxxxxxx> wrote:

>TKM wrote:
>
>> "G. Morgan" <alarmpro@xxxxxxxxxxx> wrote in message
>> news:cnt6o2p66td2u9s7k2pntcrjg8v6voadrr@xxxxxxxxxx
>>
>>>On Fri, 15 Dec 2006 21:24:59 -0700, AZ Woody <reply@here> wrote:
>>>
>>>
>>>>Dave Houston wrote:
>>>>
>>>>>G. Morgan <alarmpro@xxxxxxxxxxx> wrote:
>>>>>
>>>>>
>>>>>>Anyway,  I have never experienced what you describe (a circuit breaker
>>>>>>trip) on failure of a bulb.  My common sense tells me the arc (air gap
>>>>>>resistor) would be a great, sudden, resistance that would indeed draw
>>>>>>a large current spike.  Part of me thinks the opposite is true - for
>>>>>>which I have no basis!
>>>>>>
>>>>>>I was not aware that common bulbs had a fuse either, I thought the
>>>>>>filament IS the fuse.
>>>>>>
>>>>>>My interest in this has nothing to do with Insteon devices, it has
>>>>>>more to do with what I can do to protect the circuit for devices I
>>>>>>install, if the theory is true.  It may explain some anomalies I've
>>>>>>experienced with security devices.
>>>>>
>>>>>The tungsten-arc is for real. The built-in fuse is also. If you hear a
>>>>>"pop"
>>>>>and see a bright flash, you're buying cheap bulbs. If you hear a "poof"
>>>>>and
>>>>>notice a bit of a flicker before darkness descends, your bulbs are fused
>>>>>(even if cheap).
>>>>>
>>>>>The inrush current for an incandescent is about 10 times the current
>>>>>once
>>>>>the filament has warmed to its normal temperature. For a 100W bulb this
>>>>>means an inrush at turn-on of +8A. The "fuse", if any, built in to the
>>>>>wire
>>>>>leading from base to the filament should withstand the inrush but blow
>>>>>before a 15A breaker is tripped by a tungsten-arc.
>>>
>>>
>>>>Come on...  This is all like discussing how many angels can dance on the
>>>>head of a pin...
>>>>
>>>>In reality, don't most folks buy light bulbs at Home Depot, Lowes,
>>>>Target, Walmart, (or at their local food store if they ran short)!
>>>>
>>>>I doubt that 99.9999% of the folks would buy "fused bulbs" vs "unfused
>>>>bulbs" but will buy what's on sale..  Do you all not have a life?
>>>
>>>
>>>The fundamental question for me is whether or not light bulbs can
>>>cause equipment damage.  And no, I have no life.
>>>
>>>
>>>
>>>--
>>>
>>>-Graham
>>
>>
>> Yes, a failing incandescent lamp can cause a current surge if the filament
>> arcs as it falls apart.  That's been well known for years.  Incandescent
>> dimmer manufacturers usually handle the situation by inserting a small
>> impedance in the output circuit to protect the solid state parts which, of
>> course, act faster than the thermal fuse in the lamp.
>>
>> General service inandescent lamps are gas filled and fused.  That's because
>> when gas-filled lamps were developed in 1913, manufacturers learned quickly
>> that an arcing filament was bad for business as it caused lamps to shatter,
>> bases to melt and sparks to fly around.
>>
>> Terry McGowan
>>
>>
>I knew that UK bulbs at 230V would arc and had fuses but until recently
>I didn't think it was a problem in 120V bulbs. Where is the fuse hidden?

The lead wire from the center of the screw base is a fuse
wire.

--
Vic Roberts
http://www.RobertsResearchInc.com
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