alternator output

greasemonkey62 · Post by **greasemonkey62** » Thu Oct 07, 2010 1:00 am

I wanted better lighting initially as I had forgotten how poor 6 volt lighting was, or as everyone else had the same then I didnt realise at the time many moons ago, the only reason I am questioning the electrics is the old lucas ammeter (8-0-8) is showing a 3 volt minus with the engine running regardless of engine revs, and a 5 volt minus with the main beam on, Goffy suggested disconnecting the alternator wires and checking the current, BUT, I may not have the tester connected correctly, I understood him to mean put one end of the tester (v) to the 2 wires and the other tester lead (com) to the other alternator single wire, but I now suspect he meant put the tester (v) to the double wire from the alternator and the com lead to earth on the ac test. I hate electrics !!! give me a spanner and screwdriver anyday!! Ray.
the lights are fine now as the short on the dipswitch is sorted.

bjork · Post by **bjork** » Thu Oct 07, 2010 11:23 am

Ray, the way Goffy told you is the right way-connect across the wires from the alternator.
And I was joking a bit about blowing bulbs-there is no point in doing this, i.e. blowing the bulbs, it is just a good indicator of some decent output from the alternator-it was more of a warning that it happens if you rev the engine. You could still be right about damaged wiring, you'll just have to check!
By the way, the Ammeter is showing AMPS not volts. It should move from negative to positive as you build up the engine revs. The amount of load you apply (lights etc) will make it take a few more revs to get the load balanced, then actually charging. Do the bulb test mentioned above, it's quite illuminating.

greasemonkey62 · Post by **greasemonkey62** » Thu Oct 07, 2010 1:46 pm

This is something that doesn`t seem right to me, you are saying take the two wires that are connected together(green and black with green and yellow) and put the cicuit testers red v probe to these two wires and the black com probe to the other single alternator wire, I would have thought the black com probe should be to earth and not to another alternator wire, I never had these problems with the old sit up and beg pusher, lol.

bjork · Post by **bjork** » Thu Oct 07, 2010 1:57 pm

Yes that's it. It doesn't matter which meter lead goes to which alternator lead either, as it's alternating current, the reading is the same.
If you take a look in a manual it should show this test in pictorial form. It might also be very worthwhile investing in a Haynes Electrical manual. They cover everything, dynamos, alternators, magnetos, electronic ignition, points and coils, regulators, rectifiers, relays, ABS! even electronic fuel injection. As with all Haynes manuals, it is laid out in clear basic form so that even if the subject is new to you, you have a half decent chance of sorting things out. Try ebay, perhaps for one of these. Mine is Haynes No. 446 2nd edition.

greasemonkey62 · Post by **greasemonkey62** » Thu Oct 07, 2010 5:30 pm

ok cheers for that, much appreciated

Malleon · Post by **Malleon** » Thu Oct 07, 2010 11:53 pm

Alternatively, there is Haynes' 'Motorcycle Electrical Techbook, 3rd. Edition' (No 3471), by Tony Tranter. This is a mine of information, which blinded me with science (electrickery remains one of life's mysteries). And yes. I did fail my GCSE in Fizzics.

greasemonkey62 · Post by **greasemonkey62** » Fri Oct 15, 2010 12:07 pm

Now I have had some time to work on it I have finally managed to track down the no charge through ammeter fault at long last, it was the ignition switch internals, I don`t know exactly which bit of the switch was at fault to be honest but noticed it was not completely seated flat up to the switch top, it was only very marginally and hardly noticeable at all, but I pressed it up hard against the switch top and taped it to help stop it working loose, and started it up without really expecting any change and lo and behold there was a plus showing on the ammeter that increased with an increase on the revs, its a miracle !!!

Groily · Post by **Groily** » Fri Oct 15, 2010 12:44 pm

Ah Ray, of such small things is Happiness comprised! Well done mate and great news.
Now - if you haven't had enough playing (!?) - with your 2-wire stator and properly regulated system, you could ditch the over-complicated dodgy taped-up switch, and just have simple on-off ones - even a key as ITMA said a while back.
Can always keep the redundant one there to make it look right and fill the 'ole though.
Or - woe - carry tape at all times for when it plays up again . . .
Just in time for winter gloom too . . . good luck!

greasemonkey62 · Post by **greasemonkey62** » Fri Oct 15, 2010 1:27 pm

Oh heck!! another switch? I would like the bike to appear as close to original as I can and a different switch may look odd, and to be honest although I can wield a fairly nifty spanner and screwdriver, electrics always give me nightmares !! and I would struggle as to how to wire up a different switch without setting the old girl on fire.
Cheers Ray.

Groily · Post by **Groily** » Fri Oct 15, 2010 1:55 pm

Best leave well alone then Ray! Main thing is it all works . . . and long may it continue.
(Of course, you could alternatively . . . but no, not going there . . !)