[clug] Exercise and pay the bills!

Robert Edwards bob at cs.anu.edu.au
Sun Feb 8 23:28:05 GMT 2009

Hi Paul,

If you get an appropriate alternator (ie. 48V), you can get more-or-less
constant voltage across the range of RPMs by adjusting the stator
voltage. I believe that this is how wind-farm generators work (could be
wrong) and is how most car alternators regulate their output voltage to
give more or less constant 13.8VDC (not 12VDC!).

A (smallish) car alternator (ie. 13.8V) and a 12V-48V inverter might be
the best bet to get 48V into your power feed-in.

Hope this helps.

Bob Edwards.

btw. does anyone know how the electricity authorities "switch off"
a segment of their 240V power line (eg. for tree-clearing or other
maintenance) when there are all these solar-powered power feed-ins
popping up everywhere and effectively juicing up the line? I have
always wanted to know how they turn it all off.

Paul Wayper wrote:
> Hash: SHA1
> I'm assuming a reply to the list is what you wanted here, Brad:
> Brad Hards wrote:
> | On Sunday 08 February 2009 07:45:56 am Paul Wayper wrote:
> |> Most exercise machines sold these days just use either friction, 
> magnetic
> |> coupling or resistive loads as the 'sink' for work done.  Since Kate 
> and I
> |> are in the process of getting a solar panel system put in, and the 
> inverter
> |> can take 48VDC and put it onto the grid as 240VAC, I was thinking of
> |> getting a 48VDC generator and hooking it up to some exercise system and
> |> generating actual usable power while I work out.
> | I think this is the part you are going to have trouble with. You need 
> to sort
> | out the interaction with the storage system and the grid-connect part. (A
> | path from 240V line power to the bike isn't such a good idea...)
> The plan is to stick the 48VDC at variable amperage into the input side 
> of the
> inverter - which is already designed to cope with a bunch of solar 
> panels are
> already providing fixed voltage at variable amperage throughout the day.
> HTH,
> Paul
> Version: GnuPG v1.4.9 (GNU/Linux)
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