____ I've more-recently mentioned (within an added 'NOTE') that I'd be back by now with further explanation of an error I've posted... However I'm disappointed that it seems that NOBODY at all has any clue as to what I had done wrong with the graphs I posted.
And even after I've posted a major-clue to help tip-off what the mistake/issue is, it still seems nobody cares to venture even a guess. _ But that's probably because this thread has fallen out of activity, and-thus no-one has noticed the clue I added hours ago.
So I'm going to place this post (to bring it back into active-status), and wait a few more hours to give any somebody a chance to respond in any way they wish,, before I finally go-ahead & update what I need to get all straightened-out here.
DewCatTea-Bob wrote:basketcase wrote:If the green line is 9 degrees,
And the red line is 37 degrees
Then shouldn't we be somewhere in between them? Say... 23 degrees?
____ That's certainly of-course a naturally logical middle-of-the-road common-sense compromise which would
seem to equally split-up the expected-benefit. _ However, since the alternator produces stronger & stronger power-output as engine-revs build-up higher & higher, there's thus-then no real need for such compromise ! _ And so therefore, it's BEST to set the alt.rotor so that it's weakest PEAK-output (during kick-starting revs) is most available for the ignition's static-timing point !
The reason that no such in-between compromise ought to be considered, is because the 'peak' power-output at kicking-revs is relatively minimal, and the amount of power-production available at it's 'peak' is THEN still actually LESS (at that low-rev point), than the higher-amount of alt.power which becomes available up-near max.ignition-advance revs, (despite the fact that the alt.power is then disadvantaged 28-degrees before it's PEAK-power production-point !).
____ This above exchange was not correctly handled by ME ! _ And I'm SORRY about that ! ...
__ At the time I posted that response, I was assuming that my posted graphs were without any error, (and also, I was then in a state-of-mind which was without any regards as to the [seemingly rather minor] relevant differences between the 6-pole & 4-pole alternators).
____ I'll leave all these posts* of mine (* placed since I posted the one with the faulty-graphs), left un-updated for a few more hours, with HOPEs that at least one enlightened-soul will realize & mention what my graph-error is.
(Also hoping that my added delay with clearing-up related-things, doesn't put-off 'basketcase' too much !)
Tillater,
-Bob
PS. Of-course I realize that my recent-posts are fairly 'corny' for trying to provoke response-action to my challenge for some-one to step-forth with an explanation of why my graphs (on this page) are faulty (with a significant-error). _ But I think it's all going to help at-least SOMEbody to understand & retain this
SIX-pole mag.rotor/ign.timing matter.
UPDATE! - With anticipated-info...____ I'm fairly disappointed that NObody has responded with even a clue as to why my PREVIOUSLY-placed pic.grafts -(in white) are faulted with significant error.
I think that once I've explained what's actually wrong with them, that THEN there will be those of you who will wonder why-the-heck YOU hadn't thought of this simple/basic-oversight/mistake !
__ Anyhow, the reason for why they're incorrect is because I had made the basic-mistake of overlooking the fact that the ratio of waveform-cycles to alt.rotor-rotations is not simply 1:1 ! _ IF the mag.rotor had only TWO-poles, THEN my graphs would've been CORRECT !
However since the alt.rotor in contention here, has
six-poles (and-thus THREE complete waveform-cycles) per rotation, that in-turn of-course means that for every 1-degree of rotor-rotation, the waveform must thus-then progress
3-degrees !
So likewise, when the auto-advance range spans it's full 28-degrees (of crankshaft & rotor rotation) from static to max.advance, the corresponding-range on the alt.power-waveform then becomes a whopping
84-degrees ! _ And THAT'S what my (previous)-graphs had failed to take-into consideration !
__ So now with that point made & understood, it should now be correspondingly realized that while the PREVIOUSLY-recommend timing for the alt.rotor indeed REMAINS optimum for the STATIC-ign.timing point, unfortunately conversely however, the max.advance-point on-the-other-hand is advanced on the waveform to such an extreme point, that the alt.power is then TOO-weak (at-least at merely 3000-RPM where max.advance is first fully reached) !
__ So when Randy (quite sensibly) figured that some sort of a timing-compromise was called-for, he was actually right to think so !
The graph below shows the result of advancing the alt.rotor still ANOTHER 9-degrees (of crankshaft-rotation), for producing peak-alt.power 27-degrees -(of waveform-progression) before the static-ign.timing-point, (instead of just 0 to 3 degrees, as PREVIOUSLY thought to be the best compromise), and 57-degrees after the max.advance-ign.timing-point.
However this particular suggested setting isn't very critical, as any further increased-amount of alt.rotor advancement between 7 & 12 degrees would be about as good (as the suggested ADDITIONAL-extra 9-degrees), overall. _ (But note that your-OWN previous-proposition of a total of "23" degrees -[the original-9 + half of the 28 (which also wasn't taking into account the 1 to 3 ratio, btw)] would still not be a FAIR-compromise [for the same previously stated reason]) !
__ So NOW instead of advancing the alt.rotor just 18-degrees, as previously figured,, I now PROPERLY figure that it should be advanced a total of about 27-degrees. - Meaning that the original/factory-mark was retarded
about 27-degrees (rather than merely 18, as PREVIOUSLY assumed).
__ The below graph is actually the same as the black-ones,, I've simply broadened-out the waveform-peaks so as to better represent the waveform at kick-starting revs. _ So the fact that the alt.power-tension doesn't drop-off from peak as greatly then, means that the consumed power-pulse seems more like straight-DC (which is what the battery-powered ign.coil best feeds-on).
Also, all of the three new graphs posted on this page show only 'one & a half' -(1 & 1/2) waveform-cycles, which is what occurs with just 180-degrees -(a half-turn) of alt.rotor rotation.
DUCATIly,
-Bob
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