Hi Randy, I have done this test. I'm familiar with it. I can send video of my results if you PM me your email.
You are disconnecting alternator leads from wire harness right?
I have ohmite 100w 1ohm resistor. Use digital meter on AC volts, quality meter $60. I have old Radio Shack analog meter. Reads same.
I have only tested 2 wire alternators. Shop Manual
covers 3 wire testing, but I've never done it.
Exactly what alternator? Year of motor?
The specs change for different 2 wire alternators.
My '73 Tiger all original is tested 3k rpm per Manual
. I also tested '73 Bonnie with original Triumph Lucas
rotor & SPARX 10A stator. Both tested the same 9v AC @ 3000 Higher rpm goes higher. The resistor gets hot fast so I didn't use really high rpm.
Looking at your volts & rpm my readings were very close to yours. I tested mine just to know.
The '73 Bonnie had smoked a Wassell 16A two wire stator & Tympanium regulator failed allowing volts to go to 20 ish. Stator still charged, but was melted...
New SPARX 10 with new Lucas
4 wire 100A regulator & checked output. Was good similar to yours.
My bike works good in real life. The '73 bonnie has covered several hundred miles since repairs & continues to work good.
The great thing about this test is it tests both rotor strength & stator output at same time. So if good both are good. If bad you must substitute know good parts & recheck.
In this test set up volts = amps. Shop Manual
gives specs in volts. Go over shop Manual
carefully looking at spec sheet for alternator at hand. Shop Manual
just used regular analog AC volt meter. I found my digital meter & analog read the same. As you observed output is very rpm sensitive.
Yes alternator is just barely large enough to handle the load. Fine for country riding. Extended city riding or extended stop/go riding the voltage will go low. They can effect spark at a point especially with EI. Telltale your getting low is flash speed of turn signals if equipped. LED bulbs can really help in city riding. At night headlight gets dim. Bright when revving though. 3 phase alternator is only real cure. It charges higher at much lower rpm. A good battery
is a must for city riding. Many of us are now using LED BPF headlight bulbs. We haven't upgraded to 3 phase. In real life riding in our conditions, much city with canyon roads, some freeway the bulbs make it workout fine.
Curious to know what bike & alternator you have. Riding conditions? Are you having problems with low battery
? It looks like your stator output is good.
Want some fun? Test the zener exactly per shop Manual
with amp & volt meters hooked up. Most interesting. It really does work. Test with incandescent head light on & off. What's your finding? That will show you what you want to know. If you have electronic regulator or no amp meter volt meter will show the volts of course which is enough to see where you're at. What fun is that?
Want more fun. Hook DC volt meter & a 21w or so light bulb to same alternator leads. Be sure to insulate the chassis connectors. Bike started on battery
power alone. Remember don't let alternator wires touch anything on bike. Start motor & rev throttle. Volts goes through the roof. My 12v bulb burned out about 25v. It will go way over 30v.
Fun stuff! Don