Swop pos + dynamo to neg - alternator

[John B]

Hi Guys -got a singer gazelle 1964 pos earth . Dynamo has died so it seemed a good time to convert to an alternator. Have bought the alternator and can modify the bracket so the pulleys line up . My question is what do I do with the wiring and converting to neg earth. Ive read about this before but cant remember exactly what to do. any help greatly appreciated . Thanks a lot John B

[Luxobarge]

Reverse the polarity of the coil

Beyond that, list out every electrical component on the car and we'll tell you whether it's polarity sensitive. Don't bother listing bulbs, as they are clearly not!

JPB on here is a bit of an expert on this stuff, so I'm sure he'll help.

Cheers!

[JPB]

Thought my ears were burning.

OK, so on the basis that one good diagram is worth several thousand words, many of which would bore you half to death, I borrowed a picture from another site. In the following image, the regulator is left in place and used purely as a junction for some of the connections. I'd tend to remove the regulator and rewire in a way that resembles the layout found in a later version of a similar car but some folk leave that on there and there's no reason not to:


Now, as Luxo said, some things will need to be reversed, these don't include motors or lamps but do include some clocks so tell us the make and model of any clock fitted to your car and I'll be able to advise further on that.

It's really straightforward whichever way you prefer to do the job (with or without the regulator as a junction box). Use new, thicker cable for the lead from the alternator's large terminal to the battery (or solenoid if that's how your wiring is laid out), I'd go for 8.5 square Millimetre cable from the alternator to the solenoid, that's safe for up to around 60 Amps, go for 10mm if you plan to fit an alternator that's likely to be required to provide 70 Amps or more.
Feel free to keep coming back to ask if there's anything you're not sure about.

expert...

Definition: Someone who has been a small drip.

[suffolkpete]

And of course the radio, if one is fitted, although a lot of radios of that vintage are switchable between negative and positve earth.

[JPB]

Even if a radio doesn't have a changeover switch, you could always remove and refit every electrolytic capacitor and detector diode the other way around and replace every PNP transistor with an NPN one & vise-versa.

Valves have a lot going for them really.

[John B]

Absolutely brilliant guys -particularly the diagram John. No radio fitted and no clock so no worries there. Will play when Ive got the bits of wire and it stops raining ! and see how we go ........ Thanks again John B

[John B]

Life isnt kind -am only just getting round to the above. Have tried to email JPB but dont think it went so here goes .
If I .......1 reverse the coil connections
2 reverse the ammeter connections
3 reverse the battery connections
4 take a big wire from the alt + to the solenoid
5 take the wire from the ignition light to the control box and re route it to the alternator-or shall i run a new wire
from the alt to the ignition light ?
6 Lose the original dynamo wiring

I shall leave the control box in situ

What do i do with the small terminal on the alternator ?
Hope this makes sense ,would prefer not to melt anything...............
As always gentlemen, a thousand thanks
Cheers John B

[johnc]

I've done this job on my Series IV Rapier,perhaps the wiring is the similar to your Gazelle.I researched it quite a bit and found advice that recommended that the ammeter be by passed as it is unlikely to cope with the higher output from the alternator and fitted a volmeter instead.To by pass the ammeter just join the two thick brown wires together and terminate the remaining wire at each end.
Regards
John

[John B]

Thaks John,interesting point. Whats the best way to connect the voltmeter?
Cheers John