Polarising new dynamo

[MMM1965]

Hi all, hope you can help, i need to fit a new dynamo to my positive earth mk1, the new one is for negative earth, can you advise me of the correct way to repolarise it for positive earth please? Lots of conflicting advice online. Many thanks.

[iain1967s]

Usually the current through the field coil will be enough to polarize all by itself the first time you run it on the car.

But if you want to do it off the car, use jumper cables or similar to connect the battery +ve to the casing of the dynamo, then briefly connect the battery -ve to the F terminal. i.e. just brush it over the F terminal 2 or 3 times until a small blue spark can be seen.

This assumes what you have purchased really is a true dynamo/generator, not an alternator (dynamator or similar) as those are not reversible.

[MMM1965]

HI, yes just a standard dynamo, thanks ever so much for your help, much appreciated.