regulator size

[tappy]

Well, I'm not sure how, but I managed to upload exactly the same image as before.
SOOO, see attached image for the proper version.

As I said I think the version you've got is the bottom one, and the one you need is the top one.

See next post for how to test the alternator output.

[tappy]

First off - no, you don't have the battery connected while testing the alternator unloaded.
All that will happen then is that you'll measure the voltage resulting from the alternator hitting about 90V AC (alternating current) and trying to murder the battery.

First off, connect just a multimeter to the alternator, set to the 0-200V AC range - picture 1. Run the engine at idle, 1500, 2000, 2500 & 3000 rpm and note down the voltage readings. You should see it gradually climb up. The voltage it will reach depends on a lot of things but I'd reckon between 60 and 100V

Suppose the unloaded alternator makes 90V, as you draw more current (amps) off it, the voltage will drop lower. I think these alternators are rated at 14V, 23A. SO, by the time you're drawing 23amps off the alternator, it'll actually only be outputting 14V.

Now, connect a chain of three 12V, 60W headlight bulbs in series (the output of the first to the input of the second and so on) - as per 2nd picture. Now as you increase the engine revs you'll see the multimeter rise to a lower value.

These have a total rating of 180W. At 14V each they want about 4.3A. Three of them in series will want 42V in total.

If you get 42V at 3600rpm then you've got a 180W alternator. If you measure 50V you've got a 250W alternator, and 55V means a 300W alternator. Each of those bulbs is now dumping 100W so I wouldn't expect them to last long at this. If you get 40V at much lower revs - say 2500rpm - then I'd add an extra bulb in.

With 4 bulbs: 52V = 240W, 60V = 275W, 65V = 320W.

The nominal 14V, 23A rating is 322W, but I wouldn't expect to get this much - I reckon if you get 280W you've done good

[jonnyr48]

hi tappy, thanks for your message. i tried to load a drawing of the stator but it wouldnt load - i drew it out in a line,as youve done, and it came out with 1 set of poles the right way up and the other set upside-down - basically showing what you said that the 2 seem to be negating each other - one flowing clockwise thru the poles while the other is flowing anticlockwise (if ive understood it correctly! ). ideally which direction is better for them both to go, or doesnt it matter? i think you may be overestimating my technical abilities somewhat! is there a very simple test to see if its working right(ish)? i do have a multimeter now, but ive never actually used one . the alternator is rated at 280watts in the manual,btw.
cheers, jonny

[tappy]

There's no "better direction" for any of it to flow - simply because it's alternating current so it swaps direction hundreds of times per second.
No, there is really no simpler way of testing it reliably that I can think of - resistance tests will tell you little in this case (and don't tell you much without a very sensitive gauge anyway).
Your only other option is try using it as it is. If it works and keeps the battery charged at 14V with lots of high power things turned on then great. If it doesn't then change the windings.

[jonnyr48]

thanks tappy, i shall change the connections to ONE of the windings, as you say,and then try it out. i'll let you know what happens (but it may not be for a while as the front ends in bits now!). thanks a lot mate
cheers, jonny

[tappy]

Well if you're game for trying something, then I'd try it as it is. There's enough of a chance that I've got the magnets' arrangement wrong and that your wiring is correct.