-ve earth to +ve earth conversion.

[ferret76]

G'day All, I have just been given a brand new generator, unfortunately it is -ve earth and my car is +ve earth. I know there is a way to reverse the polarity. Firstly:

How do you do it?

Secondly:

Is it a good idea or is it going to cause problems?

[bmcecosse]

What kind of 'generator' ? Almost ALL alternators are -ve earth, and any dynamos I have experienced can be polarised to work either -ve or +ve earth.........

[ferret76]

What kind of 'generator' ? Almost ALL alternators are -ve earth, and any dynamos I have experienced can be polarised to work either -ve or +ve earth.........

Looks like it is a Lucas C40.

[Trickydicky]

Here is a step by step guide.

http://www.mmoc.org.uk/index.php?page=322

[bmcecosse]

Oh well - a C 40 can work either way, no need to change the vehicle polarity.

[mike.perry]

You get slightly less electrolytic action across terminals with neg earth

[bmcecosse]

I think what was being asked here - is how to change the DYNAMO polarity....not the car

Just join the two terminals on the dynamo with a length of cable - and then touch the cable to the non-earth terminal of the battery.... It will run as a motor provided the fan belt is not on of course.......... And that action is enough to reverse the polarity.

[ferret76]

Cheers BMC, that's what I was looking for.