cmackay formulated the question :
Does anyone have a wiring diagram for converting an old tractor wiring
system from 6v (dynamo) to 12v (alternator)?
Thanks

The dynomo will certainly use one of those old electro mechanical
charge two or three bobin regulators. That will need to be removed and
the wires isolated. Modern 12v alternators are all pretty much the
same...

Built in rectifiers and regulator. A ground terminal/casing, a warning
light output and the main +ve output. The later needs to go to the
battery +ve.

Battery, starter motor, ignition coil, all lamps, instruments etc. will
have to be changed to 12v versions. It might be possible to have the
starter motor rewound to suit 12v, lamps should present no problems. It
might be possible to get instruments to work correctly by inserting
resistors into their 12v supply.

Other than the above, any modern car circuit diagram will provide
enough clues.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk