Date: Tue, 9 Jun 1998 16:12:32 -0700
From: Mel Ray
Win95 crashed and ate my homework- I mean my elaborate response on the hilarious AC/DC goings on. A short story- well, shorter- if y'all have a rectifier, preferably one of the solid state ones, a very good idea of the useful voltage you are getting from your alternator can be measured with the cheapest DC meter.
Translation: hook the alternator output (all of the wires, however many you have) up to the solid state rectifier, and read the DC volts- that's what you really need anyway. Anything over ~ 14.5 will be burned off by your zener ( or other favourite method of voltage regulation), This method gives a pretty good idea what engine speed it takes ON YOUR PARTICULAR BIKE to get useful no load volts.
By the way, I can't figure which Lucas Alternator puts out "several times" 10 volts at idle, (I'm happy with 10 v DC) but then I'm not a Rocker. nor a guitar player, in which case I would HAVE to have THAT ONE- YO, mine goes up to f'n FIFTY, dude...
If you need to reverse engineer your rectified DC reading into an AC value (I dunno, maybe it's a class project or something) it might work out like so: (actual) DC volts /.7, + 1.4v. (2X .7v for the drop across the diodes in the rectifier). So, if you measure, say, 18 volts DC (at maybe 3000 RPM) that would indicate you are getting (18 /.7) = 25.7, + (1.4) = 27.1 volts AC back upstream.
I would get only as far as finding more than 14.5 volts DC,(at moderate RPMs) and call it good.
All bets are off if you are stubbornly using that funny little Lucas rectifier thing.
Mel Ray Nottage
Date: Thu, 11 Jun 1998 08:25:58 +0100
From: Peter Aslan
On Tue, 9 Jun 1998, Mel Ray wrote:
[Lots of stuff on Alternator testing using a rectifier and all that]
If you or anyone are going to test the output of an alternator, either AC or DC, using a high quality meter capable of looking at 10Ghz of AC or whatever, please please remember that its all meaningless unless you put some sort of load across the output, either the AC output of the rectified DC Output.
In an ideal world, the load would be the same as the normal load applied by the bike at idle with the lights on. I could do the calculations to figure this one out but don't have the time.
The official Lucas manual tells you to use a One Ohm resistor, rated at about 100 Watts, which most of us don't have just lying around.
So, I would suggest you use a couple of bulbs, 12V ones, to draw enough current for the voltage reading to be meaningful.
Regards,
Peter Aslan (aka Captain Norton). Louden Quill Award.
10.2 Repairing the Alternator stator.
Date: Thu, 3 Sep 1998 12:11:20 +0100 (BST)
From: Joe Schofield
Somebody Wrote:
>My alternator stator is broken, the wires that connect to the stator
have
>gone hard and have cracked, showing bare wires ... is the stator history?
You can effect a long lasting repair quite easily:
1. Remove stator.
2. Clean thoroughly in degreaser.
3. Carefully excavate the 'epoxy' material back a long way until you have clean wires free.
4. Strip wires and solder new long lengths on.
5. Fill cavity with Araldite (epoxy adhesive), keeping wires well apart.
6. Fit new bullet connectors and replace stator.
This repair held up for many years and tens of thousands of miles on my bike. I only threw it away when I uprated the alternator a couple of years ago. Funnily enough, I was given the stator by a Triumph owner who was going to bin it!
Regards, Joe Schofield
10.3 Replacing the Rectifier with a solid state device.
Date: Tue, 25 Aug 1998 17:36:47 -0500
From: Bill Thomas
For those who asked:
The Radio Shack rectifier is part number 276-1185 (25 amp, 50 peak
inverse voltage)
It has bare wires so I soldered (be sure to heat sink between the soldering iron and the rectifier) spade connectors for ease of maintenance. The rectifier is marked with ~ for the two alternator connectors, it doesn't matter which goes where as it is AC. The other two are marked + & -. The 12 volt battery that fits the 6 volt box is a 12N5-3B. Chapparel catalogue for under 12 dollars but you have to get it filed for about another $3 at most shops.
Bill
Ain Vale wrote:
> > It is a full wave and I'll try to remember to get the numbers
tonight.
> > Bill
> Thanks, I really appreciate that!
> Ain Vale
> '64 BSA A50