175 electrical questions

[DewCatTea-Bob]

____ As always, thanks very-much for your well-above average post-contributions Hans !
__ I had originally meant to post some response-comments to your first-post on page-2 but got side-tracked, and then intended to eventually get-around to finally doing-so. _ However now that you've gotten up-to-speed by your own-self, I guess it's no-longer of any need to still do so.
__ So now onward with response-comments to your last two posts.....



[quote= ducwiz ...
" For me, your electrical system seems to be depicted and described in a booklet from DUCATI, called "magneto booklet" for tthe US market, "

____ Even-though I have no personal experience with the electrical-systems of any 175-models,, I agree with Hans that the schematic-diagram which his posted link leads-to (and now also posted down-below as well), is no-doubt indeed actually the correct-one for bodge's 175, (but not for the stator-model that he got along-with it).



" it clearly shows a battery powered ignition, thus it's name was wrongly chosen. "

____ I've already before posted the related reasoning for such confusion, (as is found in a dedicated thread - viewtopic.php?f=3&t=1695 ).
It seems that originally,, electrical-generators with permanent-magnets could be designed either with the magnets held stationary and-with the wound-coils spun-around (and named as an 'alternator'), or instead, the stator-coils could rather be held stationary whilst the magnets spun-around, and this-design's name was originally called a 'magneto', (thus differentiating the magneto-design from the alternator-design).
So-thus the name of the booklet called "magneto booklet" really wasn't actually "wrongly chosen" in the first place after-all !



" I just uploaded the 160's circuit schematics for comparison. It differs from that shown in the magneto booklet - there is only a single rectifier diode, but no bridge rectifier. "

____ The single diode rectifier-circuit of the 160-type charging-system merely half-wave rectifies a small portion of the lighting-coil's power-circuit so as to only supply the battery with just a mere trickle-charge, (as the battery is never called-upon to constantly power any load that would tend to significantly run-down the battery's store of power-juice).
__ I always suggest the substitution of a 'bridge-block' rectifier in place of a simple power-diode simply because the block-form is more convenient to universally mount and it's not much costlier to acquire !
So when anyone has to construct a new wiring-system from near scratch, a diode-block is readily more useful than a bare power-diode (whenever anyone may chose to retain the 160's rather weak charging-system).



" The 6V/28W alternator is mentioned, "

____ (While ducwiz no-doubt already realizes so)... it's really fairly misleading to refer to it (or any) alt/mag as actually being '6-volt' (or any set voltage-amount) !
Also quite misleading,, the factory-rating of the '28-watt' model is-not really near-about 12-watts weaker than the 40w.version, as would naturally be presumed ! ...
The '28' watts was apparently derived simply due-to just the lighting-coil's capacity to adequately power-up the stock 25w.headlight & 3w.taillight. _ (And the power provided by it's magneto-ign.circuit apparently goes un-included).
__ Anyhow,, to indicate a 6v.rating is sensible enough, cuz while the fractioned-section of the lighting-coil can muster-up enough power to charge a 6v.battery,
it's rather fairly-doubtful that it could also charge a 12v.battery as well (during below red-line eng.revs).



" it has the same wire colours as yours. "

____ Isn't that incredibly unthoughtful of Ducati though !? _ It's so very short-sighted of them to have produced more than one stator-design all employing the very-same set of colors for the connected wire-leads !
That senseless oversight certainly much complicates proper stator-model identification ! _ So now only expert-types can help shed-light on which is really which.



" Now, how to find out if your stator is a genuine 175 for battery ignition system, or a 160 type? Bob, any info, suggestions or ideas at hand? "

____ You betcha ! ...
While I-myself am certainly-not absolutely-positive, I'm still fairly-sure that most-all old Duke-models produced prior to the later 200 B-type motor, were equipped with alternators (or rather 'magnetos') that were made by 'CEV',, so that detail alone, ought-to eliminate bodge's DUCATI-made stator & rotor from being an original 175-component.
But even if Ducati-themselves produced stators for the presented 175 electrical-scheme,, the grounded electrical-design of the stator-model that bodge has, would-not work properly with the 175-scheme's grounded bridge-rectifier circuit !
__ I realize that the presented diagram shows it's "Generator" depicted as grounded,, but I believe that's just a misleading drawing-appendage (if not an outright error), because the full-wave bridge-rectifier can only fully rectify a stator-coil/winding which has both of it's output-ends separately-connected to the pair of AC.inputs of the bridge-circuit, (and the necessarily grounded neg.output of the bridge-circuit can't complete it's duty if the coil-circuit is also grounded as well !).



" Unfortunately, it does not show the inner circuit of the stator, "

____ Even without the crippled-narration of the crudely-translated English description-wording (accompanying the booklet's electrical-circuit scheme-diagram) tending to confirm so,,
just from the circuit-diagram alone, it can be deduced that it's stator must have a split power-winding (similar to the 28w.lighting-coil's) that's someway rather spread-over across both power-coils and unevenly divided-up to provide two varied power circuit options.
So unlike all later-conceived and purely Ducati-fabricated charging-systems, the old CEV-type charging-circuit scheme was rather very-much the same as the logically-conceived 'Jap.bike' type of stepped-levels of alt.power-output. _ And-so when the handlebar-switch is set to either it's '0' or '1' position, the 175-alternator's partial/RED power-winding/output is then solely provided to run the load-system (not including the headlight),, and when the switch is set to it's '2' position, then the entire alternator's fully-combined power-winding's TOTAL/(WHITE)-output is rather provided to run the load-system (which then ALSO includes the [relatively power-HUNGRY] headlight-circuit as well).
__ With such convenient accordingly matched power-supply & power-demand,, the battery's natural tendency to maintain it's voltage-level, sufficiently negates any real need for excess-alt.power-regulation.


Dukaddy-DUKEs,
DCT-Bob

[bodge]

thanks for the explanation's bob,duc.the text youve written on the schematic i found very usefull bob ,i think im finally starting to grasp whats going on there so may just plumb for the wireing scheme shown in the american market schematic illustrated. if thats possible with my stator? theres an italian ebayer selling looms for 125/175/200 models that sounds like it might be right and ide need the 3? pole light switch?

edit: just realised this wont work with my stator as mine is grounded ?

if its any help ive just desoldered the pair of coil wires soldered to the white and can confirm one is the other end of the red wire and the other goes to ground and theres no short between them.
still no ohm readings because ive got an old fluke multi meter that may do the job but i cant get my hands on it atmo so reluctant to spend out on another meter.

[DewCatTea-Bob]

[quote= bodge ...
" may just plumb for the wireing scheme shown in the american market schematic illustrated. if thats possible with my stator? "
" edit: just realised this wont work with my stator as mine is grounded ? "

____ If you're willing to modify your stator by un-grounding it's coil-winding and rather connect it to another wire-lead in place, instead,, then you could possibly do something the likes of a 175-stator's scheme, (but it might be preferable to rather choose the 160-system to go with the stator as it is). ...
__ However another factor that could tend to limit your options, is which AAU.model you have to work with your motor's ignition-system.
Can you post a picture of your ign.points-cam ? _ As then I should be able to tell you if it's intended for battery-powered ignition or not.



" theres an italian ebayer selling looms for 125/175/200 models that sounds like it might be right "

____ Are they factory-stock NOS.wiring-harnesses ?
If not,, then unless the seller is nearly giving them away, you might as well just construct your-own.



" and ide need the 3? pole light switch? "

____ Right, (as well as a 3-pole key-switch too).



" ive just desoldered the pair of coil wires soldered to the white and can confirm one is the other end of the red wire and the other goes to ground and theres no short between them. "

____ Okay then. _ Might as well leave them left like that for the time being.


Hopeful-Cheers,
-Bob

[bodge]

heres the points cam/assembly as fitted to my 175

IMAG0095.jpg

i also have this one which i picked up separately from either bike.

IMAG0096.jpg

[DewCatTea-Bob]

[quote= bodge ...
" heres the points cam/assembly as fitted to my 175 "

____ That AAU is made by 'CEV',, and-so unlike your alternator, it must be original to your 175-motor.
It's cam-lobe is-not so extensive as the DUCATI-version, and-so is somewhat more compatible with possible use for the magneto-type ign.system.
However with the use of a bridge-block rectifier, the unnecessary extended lobe-duration would then not lead to ign.coil overheating !



" i also have this one "

____ That DUCATI-unit is definitely intended for battery-type ign.systems !
__ So it now seems that you don't (currently) have the easy option to make good use of your stator's ign.power-coil,, but it could instead possibly be used to charge a 12v.battery, if you so choose.
__ If you don't really care to have a pure-stock type electrical-system, then you may still choose just about any scheme option.
(If whoever installed the 160-alt/mag had also rightfully installed the correct/corresponding AAU to go along-with as-well [for the 160 magneto-type ign.system], then you'd have little choice but to rather go-with the 160-type ign.scheme.)


DUKE-Cheers,
-Bob

[bodge]

for me i think the preference would be either

1 stick as much as possible to a std 175 type electrical system but divert the existing ignition coils output to the 6v battery thence take power from there to the ignition (possible?).
advantage being keep originality as much as possible/ pre drawn schematic / std parts list /relativly simple ?.
disadvantage cost/still not actually std

2 build a very simplified 12v system
advantage being 12v! / cost (not having to buy original type switches, ignition barrel, connectors etc)
downside i assume more complex/custom loom /not charging at low revs ?

[DewCatTea-Bob]

[quote= bodge ...
" for me i think the preference would be either "

____ Your most doable system would be most like that of the 160-system,, due-to the stator-model you already have, and-also because the 175-system would be more difficult to duplicate.

1 stick as much as possible to a std 175 type electrical system but divert the existing ignition coils output to the 6v battery thence take power from there to the ignition (possible?).

____ Of-course that's a possible scheme, but why combine the ign.system and load-system to both be dependent on the DC of a battery ? _ When instead you could keep the ign.power-coil directly powering the ign.system and rather divert it's excess-power to charge a battery, thus cut the need for a 6v.regulator-unit.

2 build a very simplified 12v system

____ Pretty-much same as above except the battery & load voltage-ratings of-course, and there'd then be no call for a v.regulator-unit at all.


" i assume more complex/custom loom /not charging at low revs ? "

____ Your wiring-harness/loom could actually be made simpler,, and while a 12v.battery does require a slightly higher RPM before it begins to charge, the relatively stronger yellow/ign.power-coil will likely still do-so at a lower RPM (than the white-coil does for a 6v.battery).



____ There are at-least a handful of different possible schemes that could be constructed for your project, so most any scheme you may conceive-of could likely be made to work for you.
However by not including the headlight as part of the system-load which the battery must power, your chosen battery can then be less robust and less depended upon !
__ Since your entire stator's complete design as it exists in whole, is-not at-all constructed similarly to the 175-type,, then in order to adapt it to power an entirely battery-dependent load-system like the 175's, you'd then have-to un-ground both stator power-coils and connect an added 4th.wire-lead and connect each (then properly isolated) power-coil to it's-own dedicated bridge-rectifier.
And even-though one of the power-coil outputs would be kept off-line whenever the headlight is-not turned-on, the power-output of the chosen/primary power-coil would likely still require 6v.regulation (during extended high-RPM running).
__ Or, with the addition of a 5th.wire-lead to the stator,, the 160-stator's RED-circuit could be connected to the '2' position and it's WHITE-circuit connected to the '0' & '1' positions of the 175-type handlebar-switch, while the output of the 2nd.bridge-rectifier (connected to the ign.power-coil) would run to an auxiliary / 'Country/City' circuit*switch (which allows you-yourself to decide when extra charging-power is called-for [instead of relying on a dumb/automated regulator-circuit]).
(*The 'country/city-switch' is due to the expectation that during country-riding, eng.revs are kept higher and-thus extra charging-power is then unneeded and-so kept turned-off,, while during city-riding, average eng.revs are too low to keep the battery charged, and-so the aux.switch can then be turned-on to help prevent excessive battery-discharging.)
For the likes of myself,, I'd more-so prefer the increased complexity of the five wire-lead stator-mod.plan, cuz I-myself have always enjoyed additional rider CONTROL options !
____ Let me know what you're now thinking, and we'll then continue to whittle-down your desired options towards your final scheme choice.


____ Here's a link to another related thread which you may find of interest to read-through... viewtopic.php?f=3&t=1566&hilit=ign.power-coil


Duke-Cheers,
-Bob

[bodge]

if my aau can be made to work off the stator ignition coil with some power diverted to charge the battery and save the ht coil from overheating then i think my ideal would be a direct stator powered ignition so i can still start/run the bike if the battery did fail/discharge completly and a 12v lighting circuit powered by the battery as ive never liked magneto powered lights for the simple reason when riding on unlit roads having the light dim as you roll off the throttle on approach to a bend is about as bad as it gets.
is this possible ?

[DewCatTea-Bob]

[quote= bodge ...
" if my aau can be made to work off the stator ignition coil with some power diverted to charge the battery and save the ht coil from overheating "

____ It seems you've quite well comprehended all the related matters of involved concern ! ...
The battery-type AAUs normally can't be used with the magneto-type ign.systems because all the consequential extra AC that's not grounded by the points must then rather pass through the ign.coil and-thus causes it to overheat ! _ But with the positive portion of the AC that's ignored and normally wasted, instead rather diverted away from the ign.circuit,, the ign.coil can then rather comfortably handle the remaining extra duration of mere neg.current-flow (that's resulted by the longer lobe-duration of the battery-type points-cam).



" then i think my ideal would be a direct stator powered ignition so i can still start/run the bike if the battery did fail/discharge completly "

____ That's ideally true, and that's the quite logical idea I've most often suggested for others to sensibly consider.



" a 12v lighting circuit powered by the battery as ive never liked magneto powered lights for the simple reason when riding on unlit roads having the light dim as you roll off the throttle on approach to a bend is about as bad as it gets. "

____ While I-myself quite fondly love to hear the exhaust-note upon engine-braking deceleration, I thusly rarely bother to pull the clutch and let the revs drop whilst rounding a road-bend ! _ However I surely wouldn't disagree that there exits good reasons for having the advantage of a headlight that doesn't depend on a running motor.



" is this possible ? "

____ Certainly ! _ As as I had previously indicated, most-any scheme conceivable could be feasibly worked-out (with advantageous trade-offs).
__ With the pos.output of the ign.power-coil kept diverted to help keep a 12v.battery charged (under all power-demand conditions), the lighting-coil's switched output could be brought on-line for whenever the headlight is turned-on,, thus still avoiding any need for any automated-type regulator-circuit.
However this scheme really ought include a std.sized battery, as one under 5-amp/hrs would be rather hard-pressed.
__ You can logically understand that simple (non regulated) DC.conversion of the lighting-coil's AC.power will still pretty-much provide the same amount of power-juice for still running the same 28-watts worth of lighting,, and along-with the added 10 ~ 15 watts provided by the diverted pos.DC from the ign.power-coil, you could thus-then run a 30 ~ 45-watt headlight (depending-on whether you mostly do city or country riding).

____ So does this proposed scheme fill-the-bill for you, or do you yet still have other concerns to further consider getting all ironed-out ?


Hopeful-Cheers,
-Bob

[bodge]

yes that sounds like a plan riding would be mixed but all the best roads are unlit so optimising the headlight would be good, std battery would be fine. ide need a second bridge rectifier for this setup ?
ive got an old miller 3 position handlebar switch with horn and dip/engine kill? push buttons and if i could use cheap universal ignition switch and coil that would save me a few quid