Monza Jr 160 diode/regulator question

[DewCatTea-Bob]

____ Sorry I've been pretty-much off-line for the past month, (and still have limiting issues to get fully ironed-out) !

____ I've been somewhat disappointed that you had let your past thread -( viewtopic.php?f=3&t=1566 ) on this same topic become unfollowed-up on back when your project-case was still of particular interest to me and still well known-of in my mind,, as now, (so much later and within a NEW-thread), it's become too fuzzy in my mind to properly address competently & efficiently. _ And-so we thus have to get refreshed as to exactly what you most prefer to get accomplished.
As I last recall, you were intending to rewire your alt.stator (AGAIN),, and this-time more logically, and-also so that you could choose to wire-up things in any number of fashions (which you were supposed to pick one of and carry-on forth-ward).
It may be easier for all to follow-along, if you rather continued-on from where we had left-off, in your other (already established) thread.


[quote thatnameisal ...
" I installed one and connected everything...I know the diode is going to get warm, but it got down right HOT HOT HOT "

____ You must certainly have something wired-up WRONG ! ...
__ I believe the stock rectifier/power-diode was merely a 1-amp version (and certainly not more than a 4-amp),, and under normal conditions, it would never even get warm, as it was never expected to conduct little more than about a half-amp of current-juice.
So the fact that your diode gets "HOT", means that you've got your wiring screwed-up somehow !



" I guess I can switch the polarity and try again, "

____ That won't help, as the factory-intended (LOW)- power-circuit is incapable of overheating any power-diode of over a quarter-amp capacity.
So rather, it's the particular circuit which you've got connected-up that's at fault.



" Any thoughts? "

____ Yes, we have to realize exactly what wiring you've got hooked-up to everything, and then get it properly straightened-out correctly.
__ I had before expected to guide you further (from within your other/older thread - viewtopic.php?f=3&t=1566&start=40#p11739 ), but it seems that you've since jumped-ahead on your own (and got lost somehow).


Hopeful-Cheers,
-Bob

[thatnameisal]

____ Sorry I've been pretty-much off-line for the past month, (and still have limiting issues to get fully ironed-out) !
As I last recall, you were intending to rewire your alt.stator (AGAIN),, and this-time more logically, and-also so that you could choose to wire-up things in any number of fashions (which you were supposed to pick one of and carry-on forth-ward).
It may be easier for all to follow-along, if you rather continued-on from where we had left-off, in your other (already established) thread.

Ahh - the update: Re-wound the charging coil with the same size wire and the exact same number of windings. The charging output came up to 0.2ohm which is what we were looking for, but the headlamp lead only ever got to 0.4ohm while we were looking for 0.7. As I was researching your numbers I found in the supplement to the shop manual as well as one of the one-page updates from Ducati, they recommended unwinding one complete layer from the lighting/charging coil which actually would reduce the resistance. I didnt unwind it, but rather left it wound exactly as the original.

Per your suggestion, I ran a ground wire from the ground on the charging/lighting coil to the the headlamp.

As for the diode/regulator...I ordered a 35A 100V and it works just perfectly, although it is a bit bigger. I am convinced the first ones I ordered were for a positive ground system which led to power going the wrong way and heating the diode so much...

In any event, the bike was up an running with lights a blazing - even at low rpm

So thank you for your follow-up and your assistance before. I will post complete set of pics from start to finish if anyone is interested.

Tomorrow I go to the DMV for VIN inspection and hopefully title

[DewCatTea-Bob]

[quote= thatnameisal ...
" Ahh - the update: Re-wound the charging coil with the same size wire and the exact same number of windings. "

____ Oh-yeah, right,, I now clearly recall being concerned with what you might choose to do to address the issue concerning exactly why your ohm-meter readings were not as expected for your lighting/charging power-coil, and being very much interested whether you may replace or rewind that power-coil !
So did you end-up rewinding it yourself, or have it done for you ?
(It would've been of considerable interest if you had kept us abreast of your progress as it was occurring.)



" The charging output came up to 0.2ohm which is what we were looking for, "

____ I gather that you rather mean that the charging-winding / (white wire-lead) resistance-level has now become rather improved to the expected ohm-reading.
__ This new revelation tends to confirm the suspicion that the original coil-winding had developed a short-circuit (possibly between it's coil-winding loops).
So did you notice any deterioration effects of the insulation-coating on the original winding-wire (which may've allowed short-circuiting) ?



" but the headlamp lead only ever got to 0.4ohm while we were looking for 0.7. "

____ Actually, as I recall,, the main-lights power-winding / (red wire-lead) ought-to be about 0.45-ohms, and the .7 ohm-figure is roughly for both of those power-circuits measured combined-together in series. _ So it seems that you've got your lighting/charging power-coil properly repaired.



" I found in the supplement to the shop manual as well as one of the one-page updates from Ducati, they recommended unwinding one complete layer from the lighting/charging coil which actually would reduce the resistance. I didnt unwind it, but rather left it wound exactly as the original. "

____ Perhaps your particular lighting-coil was already the updated-version with the shorter winding-length.
__ The reason for that (seemingly bass-ackwards) modification is to better match that power-coil's impedance-level to the resistance-level of the intended headlight-filament's resistance when heated-up to it's best light-intensity.
So the expected benefit (of the recommended mod) could possibly just as well be also accomplished with a re-balancing of the chosen head & taillight bulb-filaments.
I really don't think the expected improvement is really worth it for anyone to bother with doing all the related work of going through the involved trouble of removing a layer of coil-winding, (as the factory had once found worthy, with THEIR tested lighting loads).



" Per your suggestion, I ran a ground wire from the ground on the charging/lighting coil to the the headlamp. "

____ That's a fairly important wire-circuit to have added, as the otherwise relied-upon ground-type circuit (through all the related frame-parts) can likely be insufficient for good head-lighting !



" As for the diode/regulator... "

____ Such power-diodes do-NOT also act as a 'regulator' !
And it's just as well for your charging-system, as it's power-output merely provides just a trickling amount of power-juice to keep the battery charged (as the battery most-usually keeps it's stored juice undrawn from).



" I ordered a 35A 100V and it works just perfectly, although it is a bit bigger. "

____ That's WAY-overkill, as a much smaller 4-amp/50v power-diode would be more than sufficient for the job, and could be had from any Radio Shack for under 2-bucks !



" I am convinced the first ones I ordered were for a positive ground system which led to power going the wrong way and heating the diode so much... "

____ Certainly the polarity of how you had your diodes connected, could indeed make such a difference ! _ But there's no-way that the power available from the charging power-winding could notably heat-up any actual 'power-diode', as the available charging-power is way too insufficient !
This brings-up what I had previously stated in my prior-post...

" I guess I can switch the polarity and try again, "

____ That won't help *, as the factory-intended (LOW)- power-circuit is incapable of overheating any power-diode of over a quarter-amp capacity.

(* Meaning in regards to alleviating the diode from being overheated by any power-winding, [even if the connected load is a 0.0-ohm short-circuit].)
____ Actually, flipping-around the polarity-connection of that previously-installed diode, would've quite likely solved your "HOT" diode issue...
Before, when I replied the first-time,, you had not mentioned that you had discovered your HOT-diode issue only AFTER you must've also connected-up a charged battery to the diode-circuit, which in such case if the diode-polarity is reversed (from that which is normally required), the battery's relatively-unlimited supply of current-power would've then short-circuited through your new diode AND your new power-coil/winding, thus-then COOKING both of those new items !
Hopefully you did-not leave the battery & diode connected that way for very long and cause harm to your power-coil's new wire-winding, and-also didn't try that trick repeatedly and thusly tend to demagnetize your alt.rotor !



" the bike was up an running with lights a blazing - even at low rpm "

____ I wonder what the rated wattage of your headlight-bulb is ?
__ The headlight-lighting on those later 28-watt AC.powered models was always pretty-much seemingly bright enough, (except at low idle),, so it seems that the magnetic-strength of your alt.rotor magnets still remains up to par.



" I will post complete set of pics from start to finish if anyone is interested. "

____ Oh YES, very-HIGHLY interested in that ! ...
As I believe you've done a very good job, and it should make a GOOD-example for others to follow !!


Hopeful-Cheers,
-Bob