The TRWs are 6 volt...Changing them over to 12 volts isn't entirely straight forward...If an alternator with 3 output wires is fitted, then joining any two of the three wires together will turn the existing unit into a 12 volt alternator...All bulbs, the rectifier, the battery, the horn and the capacitor will have to be changed to 12v items...
As the system at 6 volt is regulated by switching the coils of the alternator in or out depending on system load ( there was no purpose made regulator for 6 volts..), the basic wiring circuit is not suited to 12 volt operation...
So it will need to be rewired, with the new system incorporating a 12 volt Zennor diode and heat sink to regulate the output..
The diagram for any 12 volt machine will do for the basic wiring layout but adapting that to function with the existing switches will require some experimentation....It does work though, I did the conversion on a friends TRW about 25 years ago!....Ian
My '55 Triumph 5T is build like Ian decribes, also with a zener diode (I suppose they didn't exist back than)on an aluminium plate.
Works very well at 12 volts for many years now (fingers crossed !!)
