ecurbruce wrote:I need some assistance in thinking through the way my alternator is wired to the voltage regulator.
I have a 12 volt regulator that negative grounds through the case to the chassis, and has three pins, one to the battery by way of a relay, and two positive pins to connect the alternator to.
The alternator is the one that I modified to a six coil to fit into a narrow case engine. ( see six coil alternator in a narrow case 250
by ecurbruce » Wed Apr 06, 2011 11:45 pm(currently on page 21 of this forum...). The alternator has four wires exiting the case, black, green, white, and red. The two sets of series coils are isolated from eachother.
The white wire and the red wire have continuity, and so are connected to one set of coils. There is 5 ohms resistance.
The green wire and the black wire have continuity, and so are connected to the second set of coils. There is 4 ohms resistance.
There is no continuity between the two sets of coils,(ie-black is isolated from red, white,, green is isolated from red, white,, red is isolated from green, black,, white is isolated from green, black.) the black wire is connected to the alternator in the position of the original wire connection, as is the white wire to the other original position. The green wire and the red wire are connected to their respective coils where the original ground was lifted from stator.
I prefer to wire this circuit in parallel, so as I understand it, here's how I routed the wires; black wire, white wire together on one of the positive terminals of the regulator, green wire, red wire together on the other positive terminal of the regulator. - Parallel, as simple as that, right?
Well... Wired this way, the system produces no power...
Next, I disconnected just the black wire, so as to disconnect one of the series of coils, and the system supplies power in this configuration, with just one series of coils connected!
Connected this way the charging system acts predictable, in that the headlamp gets brighter as RPM's go up, and the voltage regulator is supplying voltage to the battery as the RPM's increase.
So now I'm second guessing what I believed is the way to connect the alternator in parallel. Is it as easy as paring up the wires from the series of coils onto the two positive terminals on the regulator. Am I missing something obvious here?
Looking for ideas, before I proceed with swapping wires around,
Bruce.
____ First-off, since you knew where your original-thread could be found, I'm left to wonder what you reasoning was for starting ANOTHER thread concerning your modified-alternator ??
__ Anyhow I believe I know what's-WHAT with your plight and it seems clear that you should've come here FIRST with your intentions, to get top-notch advice ahead of time.
There are so MANY points I'd like to start-out with FIRST, but I'll just have to do the usual-response and tackle things in the order you've already established. ...
" I have a 12 volt regulator that negative grounds through the case to the chassis, "
____ Can you post a pic of your regulator-unit ? _ Do you KNOW whether it includes a F-W.rectifier ?
" and has three pins, one to the battery
, and two positive pins to connect the alternator to. "
____ If the unit includes a rectifier, then the post-pins/terminals that are meant-to connect to an alternator are NOT "positive" ones I ... Rather, they're actually 'AC.inputs'.
" The alternator is the one that I modified to a six coil to fit into a narrow case engine. "
____ As I recall, you (trickily) installed an additional pair of (
unmodified !/?) stock-type power-coils to an otherwise stock 6-pole n-c.stator, so as to emulate the workings of a standard w-c.stator,, is that not correct ?
" The alternator has four wires exiting the case, black, green, white, and red. The two sets of series coils are isolated from eachother.
The white wire and the red wire have continuity, and so are connected to one set of coils. There is 5 ohms resistance.
The green wire and the black wire have continuity, and so are connected to the second set of coils. There is 4 ohms resistance. "
____ Alright, in other-words, (similar to a w-c.type alt.winding-arrangement *),, you have two separate/isolated stator-windings which both wind-through all six power-coils, (* except that you've avoided the w-c.type's red/common-lead). _ And-so you've got a white/red-circuit and-also a black/green-circuit.
__ (It was smart to rather make-use of 2-PAIRS of wires-leads, [and-thus avoid employing a common-lead] !)
____ Your stated "5 ohms" & "4 ohms" seems rather high to me. _ So did you actually mean '.5' & '.4' ohms ?
" the black wire is connected to the alternator in the position of the original wire connection, as is the white wire to the other original position. "
____ So your WHITE and your BLACK wire-leads are connected to the alt.stator
in-place of the original yellow wire-leads...
__ That's smart in that just as white & black are 'opposites', SO ARE the polarities of the terminals to which they're connected !
" The green wire and the red wire are connected to their respective coils where the original ground was lifted from stator. "
____ While not the best color-choices, that is advantageous to keep the two stator-circuits isolated, (instead of using a 'common', or especially direct-grounding,, as Ducati has economically-done).
____ I prefer to wire this circuit in parallel, "
____ Did you have the two stator-circuits connected in 'series' before ?
If-so, it didn't really matter either-way, PROVIDING-that your intended load-system's resulting/total resistance is NOT lower than the (then extended-single) stator-winding's maximum 'impedance', (which would be somewhat even-higher than the .5+.4 total 'resistance' !)
__ I'm wondering exactly-why you have come to choose to arrange the two stator-circuits in 'parallel' ? _ Is it because you've read & understood my postings within the thread (posted by Nick) about the related magazine-article ?
__ Anyhow, if you intend to power a load-system with LOW-resistance, (like under 1-ohm),, then it's fairly-
important to employ a 'parallel' alt.winding-arrangement, so as to make-sure that MOST-all produced alt.power is rather spent on the intended LOAD-system (instead of significantly-partially wasted by the stator-winding itself, [as would certainly be the case with the simpler series-arrangement] !) !
" so as I understand it, here's how I routed the wires;
black wire, white wire together on one of the positive terminals of the regulator,
green wire, red wire together on the other positive terminal of the regulator. "
____ A COUPLE of problems (coming-up) with that ! ...
__ First-off, when you state: "positive terminals of the regulator", certainly you must RATHER-instead ACTUALLY-mean the 'AC.input-terminals' of the 'rectifier', RIGHT ?
" - Parallel, as simple as that, right? "
____ That's indeed in 'parallel' , BUT-NOT so
simply ! ... While you then sort-of have the two stator-windings parallel-arranged in a 'PHYSICAL-manor', you then ALSO have them connected '
electrically' in a
SERIES-chain, (since you've then connected those two power-circuits
head-to-butt & butt-to-head, [instead of head-to-head & butt-to-butt] !) !
" Well... Wired this way, the system produces no power... "
____ Well that's
NO-wonder ! ...
The
ALTERNATOR-itself is then certainly still producing power ! _ BUT you then have it's two power-circuits directly SHORT-circuited to
each-other !! _ So the alt.stator-itself is then it's-OWN one-&-only load !
So of-course there's then no reason for any power to be left to enter-into your regulator-unit !
" Next, I disconnected just the black wire, so as to disconnect one of the series of coils, and the system supplies power in this configuration, with just one series of coils connected! "
____ Right,, cuz that way, you've then opened-up & eliminated the (major !) short-circuit, thus-then leaving ONE of the power-circuits to enter-into your R.unit !
" Connected this way the charging system acts predictable, in that the headlamp gets brighter as RPM's go up, and the voltage regulator is supplying voltage to the battery as the RPM's increase. "
____ Right, just as ought-to be
expected, (even-though you're then only feeding your charging-system with just half* of the alternator's possible power-output) !
(* If your 6 power-coils are still dual-wound as stock-Ducati, THEN that "half" is-NOT
50% ! _ As the mutual-induction effect between the two alt.power-windings will dampen power-output, depending-on actual-load & RPM !! _ So in the case of
full-wave rectification, use of only-ONE of the power-circuits will then produce OVER 50%, of both together !)
" So now I'm second guessing what I believed is the way to connect the alternator in parallel. "
____ Good-thing too ! _ You should've done-so sooner. ...
Cuz even if you had CORRECTLY-arranged the two stator-circuits in true/complete parallel-configuration 'ELECTRICALLY', you'd
still be wasting some power within the alt.stator-itself ! ...
Because since your two stator-windings didn't have absolutely-
IDENTICAL ohm-readings, ONE will see the other as a 'LOAD', (and-THUS waste some power [through whichever stator-circuit has the least impedance] !) !
And you really DON'T-want ANY of the power produced by the
strongest power-winding, to-be able to have any chance to see the
weaker-one as a partial-load (and-thus cancel-out an equal-amount of power from the weaker alt.winding, or even possibly become wasted as additional heat) !
" Is it as easy as paring up the wires from the series of coils onto the two positive terminals on the regulator. "
____ Well, that would've helped somewhat but,, NO, not-really. _ (As the two stator-windings are-not EXACTLY-matched [as it seems they ought-to be].)
(And once-AGAIN, the R.unit's terminals which the alternator-outputs are supposed to-be connected-to, are-NOT "positive terminals", (but rather 'AC.in' [or marked with '~' ] ) !
" Am I missing something obvious here? "
____ I'm afraid-SO. ...
IF it were-ever actually-OK to connect BOTH stator-circuits only-to just-ONE bridge-rectifier,, then
why-bother to connect-up TWO-pairs of wire-leads to the stator for routing-outside and-THEN become connected-up together EXTERNALLY,, when (in such case), that paired-connection COULD've instead been done
internally at the stator and then routed-outward (to the rectifier) with JUST
ONE-pair of common wire-leads ! ?? _ THAT simplified-practice is just not professionally-done,, so clearly it's not good-practice to directly-connect together two separate power-sources to one charging-system, without first isolating the power-sources from one-another.
__ So it doesn't make much sense to connect BOTH pairs of alt.wire-leads to the very-SAME bridge-rectifier, (even if THAT wasn't a problem of it's own) !
" Looking for ideas, before I proceed with swapping wires around, "
____ You should just try-out only one power-circuit at a time, to find-out whether that provides enough charging-juice to suit your needs. _ And if nether-one alone is sufficient, then connect-up a SECOND bridge-rectifier for the second power-circuit.
__ OR, you could also try-out a
dual half-wave rectifier (like from a pre-1975 L-twin), and possibly discover that THAT charging-system arrangement suits your needs, (by properly taking advantage of Ducati's mutual-induction circuits).
__ Do you know the total-resistance of your combined load-system ?
____ BTW Bruce, wasn't it YOU who once began a rewind-job on a 6-pole stator-core ?
Hopeful-Cheers,
-Bob