Posted by Jim Wilkins on December 9, 2008, 7:38 am
On Dec 8, 10:25 pm, david.willi...@bayman.org (David Williams) wrote:
> -> The only place I've seen this work is in an LED standard lamp - you
> -> manually lift a mildly heavy weight from floor to 5' off the ground, then
> -> it falls slowly while running a generator (through a gearbox) for a
> -> couple of hours.
> Hmmm... Suppose the weight is 20 kg and the height is 1.5 metres. So
> the amount of stored energy is (mgh) 20 x 10 x 1.5 or 300 joules. So at
> 100 percent efficiency, it would run a 1-watt LED lamp for 300 seconds,
> or 5 minutes.
> I don't think I'd buy one.
> dow
You could use it to power a quartz clock mounted at the top of a tall
cabinet. It would need some mechanism to control the weight's descent,
perhaps a slowly swinging pendulum escapement.
Posted by Saint Isadore Patron Saint of on December 13, 2008, 3:43 am
> On Dec 8, 10:25 pm, david.willi...@bayman.org (David Williams) wrote:
> > -> The only place I've seen this work is in an LED standard lamp - you
> > -> manually lift a mildly heavy weight from floor to 5' off the ground, then
> > -> it falls slowly while running a generator (through a gearbox) for a
> > -> couple of hours.
> > Hmmm... Suppose the weight is 20 kg and the height is 1.5 metres. So
> > the amount of stored energy is (mgh) 20 x 10 x 1.5 or 300 joules. So at
> > 100 percent efficiency, it would run a 1-watt LED lamp for 300 seconds,
> > or 5 minutes.
> > I don't think I'd buy one.
> > dow
> You could use it to power a quartz clock mounted at the top of a tall
> cabinet. It would need some mechanism to control the weight's descent,
> perhaps a slowly swinging pendulum escapement.
Yep, Dow and 3M both got the development, manufacture and sales of
them.
WOMP WOMP
Tom
Posted by Saint Isadore Patron Saint of on December 13, 2008, 3:43 am
On Dec 9, 7:52 am, david.willi...@bayman.org (David Williams) wrote:
> -> You could use it to power a quartz clock mounted at the top of a tall
> -> cabinet. It would need some mechanism to control the weight's descent,
> -> perhaps a slowly swinging pendulum escapement.
> I have a quartz clock with a dial that is illuminated with LEDs. The
> clock runs off an AA cell. The LEDs are powered through a transformer
> and rectifier from the AC supply.
> LEDs need a *lot* more power than clocks.
> dow
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> -> manually lift a mildly heavy weight from floor to 5' off the ground, then
> -> it falls slowly while running a generator (through a gearbox) for a
> -> couple of hours.
> Hmmm... Suppose the weight is 20 kg and the height is 1.5 metres. So
> the amount of stored energy is (mgh) 20 x 10 x 1.5 or 300 joules. So at
> 100 percent efficiency, it would run a 1-watt LED lamp for 300 seconds,
> or 5 minutes.
> I don't think I'd buy one.
> dow