Selfsufficientish.com

whitelegg1 wrote:Quick thought...

Would it be possible to have the gear set up as follows to create a much higher gearing.

Have a largest front ring you can find/fit, have the smallest rear cog you can find/fit, then also at the rear have one of the 'megarange'tm massive rear cogs.

Run another chain from this to the cog on whatever you will be using to actually generat the electricity.

I may be missing something but I tought chains and gears were an incredibly 'efficient' way of transfering power.

Properly set up and maintained, chain-drive efficiency can be as good as 98.6% (see this page). Unfortunately running a small rear cog will reduce that efficiency, as will running Derailleur gears.

The problem with running very high gearing -- especially twice as above -- will be applying enough torque to get thing turning in the first place! Plus you have twice (or more) the power loss of a single-chain setup. I guess you'll have to do the same amount of work to generate a given amount of electricity, but you will have to work harder for a shorter time period.

My own feeling is that the time and money used up in creating a two-chain system would be better invested in optimising the generating part of the setup, perhaps adding a fly-wheel or larger homemade permanent magnet alternator. YMMV.

Nigel

yes, Nev, inspired by the very same book (sadly out of print).

It is a good book, Judy, I picked it up back in the eighties and it is still in my library. Every so often I look over it and get enthused again, but nothing has come of it yet, apart from my abortive attempt to generate electricity.

Nev

Time to dig this one up!

The thinking now is to provide the power for a number of machines - replacing the electric motor - washing machines, flour mills, and so on.

I will revisit the sites you guys suggested. Thanks again.