Posted by Øystein Rustad (130.67.81.1) on May 08, 2003 at 12:50:24:
In Reply to: Re: Another quick clarification request - Darren posted by Øystein Rustad on May 08, 2003 at 12:47:57:
Ehhh... mixed negative and positive work there... :-) sorry..
I Just put in a comment on the question, that was directed to Darren, if I may ?
: %OU for a gravitywheel would be Input related to output where
: Input = negative work, and output is positive work acting as torque * distance acting on the axle or rim..
: OU = Wdown (negative work) / Wup (positive work) * 100 - 100
: So input is not the starting "hand-push" but the lifting of weights that the wheel is responsible for..and the work the falling weights have to perform and hopefulle have some work left to drive some external machinery :-)
: Øystein
:
: : Thanks Darren for the earlier clarification...
: : In that previous post, you said that a thoeretical design you had worked on "also produced OU (about 20%) "
: : I`d be grateful if you could explain in general terms how you arrive at a figure for "O/U" in the context of a gravity wheel.
: : To say something produces 20% more than unity implies IMHO that you have a notional value for "input energy" (or rather work, because in such a wheel gravity is constantly putting energy in)
: : I can see how one quantifies output energy (and given a rotational speed) work, but how do you quantify the 'input energy' bit?
: : If you start from "energy needed to start the wheel" then you end up with an absurdity, because if the output power is thereafter 'always available' the ratio of output/input power keeps rising - the aggregate value for "output power" grows with each revolution.....(even if the machine limits its own speed due to friction etc, there is always an increasing value for output power)
: : Or do you mean that the available turning force is 20% greater than that for a unity machine...? But that can't be right either because in the latter case the aggregate turning force is zero (a unity machine does not turn by itself). Therefore the ratio
: : torque of O/U design
: : --------------------
: : torque of unity machine
: : will always be infinite (because the lower term is always zero)...
: : How are you quantifying the 'input bit' to arrive at a notional 20 % O/U in this context?
: : Thanks
: : Nick