Alternator wiring

[Kmp]

Hi all,

i have recently purchased a rotek alternator as it fits the Ford 3 pin plug, how ever it has a few
more connections on it and I don’t know how to wire it. I have changed from a crossflow to a pinto so need to change the wiring, but googling it I can’t find out what connections are actually for what.

The instructions are useless as there is no wiring information on them.

could anyone please tell me what wires need to go where? I can find info on Bosch and Lucas ones but not for what i have.

How well does it work to send the output (battery charging cable) through the starter motor cable? When I have been searching previous posts I see that some have done this.

thanks
kris

[Graham]

the alternator plug you have there will plug straight into the alternator.

its common to connect the main charge lead from the alternator to the main starter feed cable, lots of car manufacturers do it, it saves on wire!

[Kmp]

So just to check, the centre wire in the 3 pin plug which is the old large ish red cable is fine to be connected as it was into the centre connector of the alternator?

Does it need to be earthed?

[katana]

So just to check, the centre wire in the 3 pin plug which is the old large ish red cable is fine to be connected as it was into the centre connector of the alternator?

Does it need to be earthed?

The body of the alt. is earthed through the mounting to the engine.

[Graham]

The body of the alt. is earthed through the mounting to the engine.

its is, but if you have proper mk2 RS2000 alternator bracket and adjuster you should add an earth because they are rubber bushed so insulate the alternator

[Kmp]

Yeah it is an rs2000 one so will earth it separately, thankyou for your help

[Miniliteman]

On a std RS2000 the alternator is earthed through the adjuster-bracket.
Within the 3 pin plug the 2 bigger pins are connected inside the alternator; there will be 2 thick red wires that run in parallel to the battery + . The 3rd smaller pin is for the charging light on the dash.
On some alternators there is a separate B+ terminal where you can fit a suppressor (condensor) to. And a W+ terminal which can be used for tach-reading on diesel engines and/or the electric heater element on a carb.

[Kmp]

Excellent, thankyou for explaining it all, that clears it all up perfectly, it will be earthed through the adjuster bracket as you say, so that’s easy.

Thanks
Kris

[GavinR]

Hi Kris,

If there is only one big red wire going to the alternator plug (as it looks in your picture), you should run another red cable of a similar size to the other large terminal hole so the current from the alternator is carried through 2 wires not just one.
Also, it is a good idea to insulate / cover / tape the B+ terminal that is not used as this is live when the engine is running.

Thanks
Gavin

[caprimk1v4]

Hi,

The B+ terminal should be live all the time, not just when the engine is running, the alternator is always across the battery, as the output is not switched.

[Marti]

Apologies for regurgitating this old thread but would like help on this item for a Pinto.
I have changed my burned our loom to a new Xflow loom and am about to extends the alternator wiring etc but I I have only two wires (a thick red & smaller blue) going to the alternator plug. I have untapped the old loom which has been well butchered in the past and see that someone has soldered in two red wires into the single red wire that feeds to the alternator. Is this really necessary as if I've read this right the pins inside the alternator are linked. It just seems odd if its not totally necessary. As always your assistance is greatly received.

[Miniliteman]

The two wires are there to share the amperage from the alternator. 45 or even more Amps is a too much for a single wire. Also, I never solder wires unless it's for very low amp connections for a sensor for example.

PS: why did the old loom burn out?

[Marti]

Hi, thanks for your reply.
So I will connect two reds to the single red further up the loom then extend them including the blue wire to reach the alternator, I can use the old plus which had three pins.
As we speak I’m pulling back the loom tape to te exit the coil feed from the main loom and come across another double insulated with criimped to the black & yellow coil wire? Why would that be, it looks like a factory crimp.

[Marti]

IMG_5188.jpeg

[Miniliteman]

The wire (grey insulation?) is the resistor-wire for the coil. During normal operation this wire is in series with the OEM coil to limit the current through the coil. When starting, this wire is bypassed via a terminal on the OEM startermotor so you get the full voltage onto the coil for better spark (voltage drops during starting) and better starting. If you have an electronic ignition then most likely it will need a full +12 Volts all the time so the resistor wire should be removed or bypassed. I made a how-to in the "how to fit electronic ignition" sticky-thread.

[Marti]

Top man, thanks for sharing your knowledge, I will be running electronic ignition so will look up the bypass sticky ��

[vannin]

Miniliteman "how to fit electronic ignition" sticky-thread, Leon I've trawled through the entire site several times, please give me a clue where this article is you have kindly written as I'd love to read it

[Miniliteman]

-> http://www.turbosport.co.uk/showthre...=102283&page=2

starts at post 57.