House wiring? (slightly off-topic)

[danial stocks]

well, actually it doesnt seem to work like that here.. a 100 watt bulb only 
draws 100 watts at or near the rated voltage printed on it.. if you lower 
the voltage it no longer draws 100 watts. if it did then it would have a 
constant brightness for all or at least a wide range of voltages - a 100 
watts dissipation in the same filament will cause the same temperature and 
thus light output.. if you lower the voltage the light gets dimmer.. thus it 
aint drawing 100 watts.. the actual current may be higher or lower than the 
current drawn during proper operation, depending on the 
resistance-temperature relationship of the filament.. as it is excessive 
temperature that causes the filament to melt, lower voltage which then means 
lower wattage should not cause a bulb to blow unless there is a massive 
surge of current.. in fact, large transmitting tubes are recommended to be 
run at a slightly lower filament voltage if you dont need the full emission, 
as it greatly increases tube life [vac tube fil is pretty much same thing as 
light globe filament]..
Cheers,
Dan
>If you test a 100 watt bulb you'll find it always draws a 100 watts, to 
>keep
>it's side of ohm's law balanced, it must draw more current (generate more
>heat) at a lower voltage. This proves true in the lab, you can quickly burn
>out a bulb buy lowering the AC voltage. Sort of. The reality is its in a AC
>environment. This means it will behave like an frequency dependant 
>impedance
>(like a speaker for example) and the actual current draw is a more
>complicated to calculate. However the ohm's law still rules. If the watt's
>remain the same and you lower the voltage the current draw will increase.
>
>
>
>-----Original Message-----
>From: Glen [mailto:mclilith at ezwv.com]
>Sent: Wednesday, December 27, 2000 11:05 AM
>To: Robert Donker; 'IXQY at aol.com'; synth-diy at node12b53.a2000.nl
>Subject: RE: House wiring? (slightly off-topic)
>
>
>At 12:44 PM 12/27/00 , Robert Donker wrote:
>
> >You have a relatively new house showing what is an extraordinary behavior
>on
>
> >your AC. This is more likely a low AC voltage (remember, a 100 W bulb @ 
>100
>
> >volts draws 1 amp, a 100 @ bulb @ 50 volts draws 2 amps) causing 
>excessive
>
> >current in the lights.
>
>
>
>I'm not sure I understand how you intended that to be interpreted. If I
>
>understand you correctly, you have just stated that a 100 Watt bulb
>
>connected to a source of 100 Volts would pass one Ampere of current. (So
>
>far, so good.) You also seem to say that very same bulb when connected to
>
>only 50 Volts would then pass 2 Amperes of current. If this is the meaning
>
>you intended, it is totally incorrect. The same bulb will actually pass
>
>less amperage when connected to a lower voltage source.
>
>
>
>Perhaps you intended to say the right thing, but it just ended up being
>
>worded in a confusing manner?
>
>
>
>
>
>As for the original problem of the man's light bulbs blowing too often, I
>
>suggest he contact a qualified electrician in his area, or his local power
>
>company for advice. There are many things which could contribute to such a
>
>situation, and it is not easy or prudent to try and troubleshoot this via
>
>an email mailing list. I can vouch for the "poor ground/neutral scenario"
>
>that another poster mentioned. That is certainly one possibility. I've seen
>
>it happen myself, but I'm sure there are others possible causes as well. In
>
>the case that I saw, some aluminum wiring had disintegrated inside the
>
>cable between the electrical meter and the breaker box. The resulting poor
>
>connection gave all sorts of crazy voltage problems, and it was a definite
>
>fire hazard as well.
>
>
>
>Since this is such a high-stakes diagnosis, I would definitely contact a
>
>fully qualified professional in my area to handle the job. If you have any
>
>serious wiring problems, it could possibly pose a serious fire hazard for
>
>your home. It might not simply be a threat to your light bulbs and
>
>synthesizer gear that we are talking about. Let's hope that you've just
>
>been buying a poor grade of light bulbs lately, but to be sure, have the
>
>situation checked by a professional to determine what is really happening.
>
>
>
>
>
>Good luck,
>
>Glen
>

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