NEWS: Water+Glass=Electricity

On Wed, 29 Oct 2003 12:24:18 -0700, Don Lancaster wrote: [Don]

Know what you mean, Don. But that's not what you said. F'rexample:

220 volt 60 watt lamp I hot = 0.27 amp about 120 volt 60 watt lamp I hot = 0.5 amp

Seventh power of 0.27 = 105E-6 Seventh power of 0.5 = 7813E-6 So the 120volt lamp lasts 78 times as long as the 220 volt lamp?

No indeed!

Brian W

I don't think so...

brian W

Then you must not use many.

Can you say "Gaussian Distribution Curve"? Harry C.

I had a lot of bulbs burn out on my garage door opener, due to vibration aging the filament. I moved the bulb to the ceiling next to the opener, and I am going on 3 years myself, with a crappy brand of bulb.

Duty cycle, and duration mean a lot. 3 years for this one is not 3 years of continuous operation. 5 minutes 6 times a day takes a long time to burn the "1000 hour" candle.

I *also* have incandescent bulbs that go out after 2-4 months, but these run nearly continuously (some 24 hours a day). The bell curve does not seem to mind that I get double the life out of them. Again, duty cycle, and duration.

David A. Smith

Yes, a 220 volt lamp run on 110 volts will run 78 times longer, more or less.

But a 60 watt 220 volt incandescent bulb will only put out 15 watts if run on 110 volts. Not much more than a nightlight.

David A. Smith

Read Brian's post more closely. According to the math, the 120volt lamp lasts 78 times as long as the 220volt lamp. When you take a number smaller than 1 (and greater than zero) to some power greater than 1, it gets smaller instead of larger.

Don W.

Golly gee mister science.

All a "long life" bulb is is one with a higher rated voltage that outputs less brightness.

??

So how would you describe that rule again?

:-)

B

"Higher rated voltage" is not strictly true. Thicker and longer filament is true. The design of the little glass "root structure" and sometimes the socket base determines the "higher rated voltage".

Sorry.

David A. Smith

Sorry Dave, but a longer, thicker filament distruted the power dissipation along an extended length and, for a given wattage, is incapable of providing the same level of illumination at the same color temperature.

It's a bit like using a more distributed heating element in a space heater, it may dissipate the same number of Watts, but it does so at a much lower temperature.

Harry C.

Dear Harry Conover:

See above where I said "But a 60 watt 220 volt incandescent bulb will only put out 15 watts if run on 110 volts. Not much more than a nightlight."

David A. Smith

Sorry Dave, you've lost me with this response.

What I responded to was your (if I have my attributions correct) words that stated:

I responsed accordingly, since a "thicker and longer filament" consuming the same number of Watts will produce less useful light and do so at a lower color temperature.

Harry C.

Dear Harry Conover:

nightlight."

A filament for 220v would be a longer and perhaps a tad thicker than an equivalent watt filament for 110v.

You were apparently assuming I meant to go from a non-optimal configuration for a given voltage. I was talking to the "use a 220v lamp on 110v to make it last longer" vein.

Sorry for the confusion.

David A. Smith

In reality, it the filament in a 220V lamp is of equvalent length but a bit thinner than that in its 110V counterpart, since for equalivalent wattage it's resistance must increase by a factor of 4 per Ohm's law.

In manufacturing lamps, the filament length is largely determined by the fixed dimensions of a standard header, while resistance is determine by the gauge of the filament.

There are exceptions to this fixed filament length, but they are rarely employed except for specialty products manufactured for critical application, such as the DuroTest bulbs once marketed for radio tower lighting use. (If it's going to cost you $300 dollar to replace a bulb on a radio tower, you can well believe that there is a market for extremely long-lived bulbs!)

Harry C.

What absolute twaddle. Where do you find the seven multipliers?

Roland

Nope, the whole of the phenomenon that is America today is built on excitement about new endeavour.

Roland

---------------- That is newspaper hype and misquoting. It is common practice to take something out of context and emphasise that, irregardless of whether it was tongue in cheek or not. Note that the maximum efficiency that I saw in the technical journal article (not the newspaper) is about 0.04% and no reference to high power generation is made. Consider that a conventional hydro plant has an efficiency in excess of 90% and there appears to be a long way to go in terms of both efficiency and power capability. The only applications mentioned in the technical journal were the of supplying low power (microwatt to milliwatt) devices. Present indications are that it is definitely not a "very practical" way of generating large amounts of energy -i.e. replacing conventionla sources.

-- Don Kelly snipped-for-privacy@peeshaw.ca remove the urine to answer

----------- Yes and it has this long life because it has a heavier filament, runs cooler and gives out less light per watt than the normal lamp. Take an ordinary 1000hr incandescent and supply it through a half wave rectifier- it will last much longer but ...

-- Don Kelly snipped-for-privacy@peeshaw.ca remove the urine to answer