alternator wiring (renault)

[andy1020]

hi all,
weird one i know but here goes. I'm doing a project with some school kids making a generator from an exercise bike & an alternator. So I got whatever the scrappy had on the shelf: a Reno Clio 1.2 alternator, 70A- should do the trick.

What I need to know is how it's wired. There's a big red lead bolted on, main +ve feed, fine. There's 2 other small wires plugged in, one white and one blue. Anyone know what these ones are? Also, is the casing ground? (The small wires don't seem thick enough for the main current from it, so I presume the casing is the -ve) Anyone know?

Cheers
Andy.

 

[davieboy]

casing is ground,yes.
iirc the blue is the excite feed (warning light). you would need to take a positive feed from the battery you want to charge into one side of a warning light (2W bulb or so). connect the other side to the blue wire. when the generator is charging the bulb should go out.

can't remember what the white wire is for.

best of luck with the project. you will need it to turn at least 2000 rpm to get it to give an output.

 

[andy1020]

great, thanks. That's what I thought...

 

[andy1020]

I've discovered that it looks like the alternator needs fed a small current to power the electromagnet before it will give a voltage. The 2 small wires (i think now they're white & green, not blue) probably provide this. It won't provide a voltage even at what looks like not 2000 but decent enough rpm. From my experience cars will normally provide something even at idle if not much, but this isn't giving anythng...

Does anyone know if this assumption abut needing current first is right? I can't find a wiring diagram for a Clio on the web, it will show me where these 2 wires go. i really just need to know if they ultimately end up being fed a current? i don't want to just connect 12V- i might just melt the small coil with too high a current, anyone know??!

 

[davieboy]

have a read of

http://en.wikipedia.org/wiki/Alternator

section on automotive alternators explains what i meant by excite wire.
also remember that when a car engine is at idle (about 750 rpm) the alternator will be turning at around 1500 rpm. the pulleys are different sizes.

 

[andy1020]

thanks for that, I realised what you meant and got it working. Hadn't thought about it enough..
Cheers.

 

[Abbeybodger]

Hi I have just solved a similar problem fitting a renault alternator to a mini digger . The other wire needs to have an ignition live feed to switch the alternator on. It's taken me a week to work it out !

 

[kkbt]

Hi All

I wish I'd spotted this last week - I'm just doing the same - this time it was a corolla with a bosch alternator.

As well as the earth and thick power lead there are three other connections yellow, red/grey, and white. Any idea's what I need to connect these to?

I guess one needs to be to the "ignition" - i.e. switch to positive,
one needs to be connected to a light bulb - but does that then connect to the positive or negative battery terminal
And the third? no idea.

Thanks for any help

kkbt

 

[JagDude]

In this cases it would be appropriate to connect each small wire via a separate bulb (i.e. 3 bulbs) to the ignition switch, then on to the 12 v battery.
Dude