450 RT Magneto

[DewCatTea-Bob]

" It did originally have just two somewhat stiff, cracked wires. "

____ That's an all too common problem ! _ The insulation-plastic used on the original alt.wire-leads seems to have been made with chemical-additives that after much engine-heat & years of life, have altered it from it's original pliable-state to some stiff & brittle-junk that's good for nothing ! _ So starting about 3-decades back, those alt.wire-leads ought to have been replaced.


" Here we go spreading this topic around to yet another thread, "

____ Since Jim gave the OKay to move all your special alternator reports to their own thread, I still plan to do so as soon as I teach myself the process (without concern of any loss).


" No, none of the Denso rotors I have are the correct diameter to work with the (unmodified) two coil R/T stator. "

____ That's too bad ! _ I'm sure a magnet-rotor with more magnets would increase power-output from the 4-pole stator.
While a 8-magnet rotor would not work, a 12-magnet rotor (with each magnet producing flux-fields as strong as the stock-rotor's), it may be possible to get up to 120-watts of power-juice from the two power-coil stator.


" I had initially planned to make an adapted mounting plate to add a third coil to try on both the Ducati 6 pole rotor and a 12 pole Denso but when I started playing with the Denso stators that idea fell by the wayside. "

____ The idea of adding a 3rd double-pole power-coil (to join the original pair), mounted on a new stator-plate with 120-degree spacing (for the 3 separate coils), and matched-up with a 6-pole rotor,, is a very interesting & workable idea ! _ I've never thought of that possibility because I would've doubted that such an arrangement could be properly fitted within the Ducati 6-pole rotor. _ (A 12-pole rotor would not have worked though, though a 18-pole rotor would have a chance!)
__ When I first discovered that Ducati updated their Monza alternator from the original 4-pole type to their newer (4-coil) 6-pole type, I was upset & disconcerted !... I didn't understand the new type and it didn't go-along with my own idea of adding two more power-coils by simply placing four coil-windings on a constructed square-core, thus allowing the continued use of the stock 4-pole rotor.



" That and when I had no success using the 4 coil n-c stator with the 12 magnet rotors, I was concerned that the 3 coil adaption mightn't work either so didn't want to waste effort better applied elsewhere. "

____ While either that Ducati 6-pole stator or your neat 3-coil idea would indeed work with a 6-pole or 18-pole rotor, a 12-pole rotor can't work together with such 6-pole stator set-ups ! ... It should be kept in mind that in order for a stator & rotor to work together as intended, each stator-pole must be matched-up together with an OPPOSITE magnetic rotor-pole than that which it's neighboring stator-poles happen to be matched-up with ! _ Otherwise -(opposite-wise), in the case of a 12-pole rotor & a 6-pole stator, ALL six stator-poles are aligned-up with the very-same (N or S) rotor-pole, and also at the same time of course, ALL of the opposite (S or N) rotor-poles are then caught 'in-between' the stator's six poles !!
Certainly you must understand that in the case of a 12-magnet/pole rotor matched together with a 6-pole stator, (or a 8-pole rotor matched with a 4-pole stator), would thus then have ALL stator-poles exposed to the very-same magnetic (N, or, S) poles of the rotor, all at once ! _ Thus no 'opposite-pole-interaction', (as is the case when each stator-pole is PROPERLY excited with the OPPOSITE magnetic-pole as it's neighboring stator-poles are excited by)! _ With either 6 or 18 magnetic-poles in a rotor matched against a 6-pole stator, the required opposing pole mix-up -(UNidentically matched neighbors) is then properly maintained ! _ But, the reason that the 12-pole rotor didn't work with the 6-pole stator is because at ANY particular pole-alignment time, ALL 6 stator-poles were ONLY exposed to (either!) just ALL 6 N-poles or just ALL 6 S-poles (of the rotor's 12 magnets), all at once ! - Thus NO opposing N/S interaction between neighboring stator-poles, (which your very-own experiment has proven to be actually necessary) !
__ So now you ought have a full grasp of that thought of yours concluding that there must be some kind of "canceling" situation occurring, between those mismatched sets of poles. _ (Although 'cancellation' isn't exactly the correct term for what's really [Not!] happening.)
__ I do realize that for some who thought they properly understood how magnets & coil-windings work together to induce current-flow (through the winding of wire), may still wonder why the 'polarity' of the passing magnetic-field should make any difference (in this case where the rotor-magnets are flying-past [right next to the tip-ends of] the coil-windings) ...
Well actually it's just the moving 'field' of the magnet's flux-lines that cause the induction of current, and thus the (N or S) polarity of the passing magnet indeed does NOT matter ! _ However the field's flux-lines need to pass-by at a 'right-angle' to the coil-windings, in order to work ! _ So these multi-pole type of stators need to have their (even-pairs) of core-fingers induced with alternated magnetism,
and that's what the rotor's magnets are actually intended to achieve as they pass by the coils' core-fingers, (and not particularly the coil-windings themselves).


" In an attempt to rearrange magnets for 'alternative results',
. . .
it seems like they must first be assembled and then magnetized afterward. If such is the case then it should be possible to de-magnetize the whole thing and redo it to function with a different stator configuration. "

____ In any case, in order to use it with the 6-pole stator, you'd still have to end-up with some number of magnets arranged so that the rotor's N/S-poles are maintained to line-up & excite every next-finger stator-pole with an opposite magnetic-pole (than that of it's next-door neighbors' ). _ In other words, ONLY every-OTHER stator-pole coil-winding shall have the SAME (N or S)-magnetic rotor-pole exciting it, (and therefore with the in-between coils of course being excited by just the OPPOSITE [not same! N or S] magnetic rotor-poles).
__ Thanks for sharing those added strange details about the Denso rotor-magnets, (as I realize that discovering those facts must've been extra taskful) !


Enlightened-Cheers,
DCT-Bob

[DewCatTea-Bob]

We have spark! Went back to basics, just to be sure. Retimed the engine, pulled the timing cover and reset the points with new point set and condenser, new plug wire. Used the yellow wire. Life is good.

____ Of all those things you double-checked Chris, which of them did you find to be the cause of your no-spark problem ?
Was all of your ignition-system's wiring already correctly set up, before ?

____ Now that you know that everything is already properly set to provide ign.spark, you should place a scribe-mark on the face of your alt.rotor, so as to be placed directly aligned with the TDC-notch of the crankshaft.
__ Then next you should check the condition of the insulation-coating of your three alt.wire-leads ! ... If any of them show any signs of cracking when sharply bent, then you really ought to replace that entire alt.cable !
__ Next, (now that your ign.spark-test has been successful), you should test-out your lighting-system...
Connect your intended headlight to the Red alt.wire-lead (& Ground of course), and see that the light's intensity is sufficient for your needs. _ (Likely it won't be if you intend to do any street-legal low-RPM city-riding, with a brake-light also activated .)
If you plan to do so, then that would put you in the same boat as Bill has been in, and so you may wish to follow the same road as he finally takes (concerning alternator mods).
On-the-other-hand, you might prefer to go the path that Jordan's been considering.
__ Got any ideas of your own concerning this issue, yet ?


Fun-Cheers,
-Bob

[sjd007]

To liven this thread up after all these years! My first post... I'm restoring an R/T and it has a two-cable alternator, white and black. The wires look newish so may have been replaced. I have never seen it running, bought it in bits, so am not sure if I should replace the alternator while I am in there. Engine number 540207 for those that are interested. It came wired with what looks like new parts - bridge rectifier and zener diode. I'm considering running the current setup to see how it goes but am really tempted to put in a new alternator so I can take out the points (and have a usable headlight). Although... LED headlamp "bulbs" can now put out as much as halogen and almost as much as HID so maybe just use the original alternator. Cheaper for sure. Does anyone know the actual output of a two-wire alternator? I have heard 40W and 70W, I kind of believe 40W especially with what is likely to be weaker than original magnets, so probably even less?...

[graeme]

sjd,
I used a LED bulb (H4 style) and they are crap to see with but good for on coming traffic to see you. (for what it's worth)
Most LED lights need 12 volt DC.
I believe 40watt is correct?
I have a few mates with RT's that use the standard system without any issues and use low wattage 6v bulbs.
Graeme

[sjd007]

Thanks for the advice Graeme. 40W isn't that much but I'm sure with an LED tail light and careful restriction of headlight consumption I can get by. Pulling the alternator (and all that entails) is slightly more than I was intending to do I'll try the stock system and run a low wattage headlight (just daytime riding anyway) and maybe upgrade the alternator / ignition if I have bother with the points / alternator output later down the track. Contactless ignition has its benefits I believe! I won't know the output until I get it up and breathing fire so a bit of a catch-22. Cheers!
Simon

[DewCatTea-Bob]

[quote= sjd007" ...
" I'm restoring an R/T and it has a two-cable alternator, white and black. The wires look newish so may have been replaced.
It came wired with what looks like new parts - bridge rectifier and zener diode. I'm considering running the current setup to see how it goes "

____ Either somebody had no idea what they were really doing, or those two alt.wire-leads are indeed new and someone also modified the alternator's internal stator connections when they connected-up the new-wires,, cuz otherwise, there's no way to make normal use of a full-wave bridge-rectifier (with a stock R/T alt.stator) !
However I'd much suspect the possibility that their electrical-concept is rather somewhat faulty ! _ Because the alt.stator has TWO-pairs of power-outputs of which one output-lead from each is normally grounded (for the stock-system),, and in order to full-wave rectify all the available alt.power, then ALL the output-leads would have to be isolated from ground ! _ And-so there now ought to be more than just one pair of alt.wire-leads, if the internal wiring arrangement has been altered to properly work with bridge-rectifiers.
__ To determine what the new wires are now connected-up to,, you'll need an ohm-meter, (to determine if the alt.power-coils have been ungrounded, for one thing).



" LED headlamp "bulbs" can now put out as much as halogen and almost as much as HID so maybe just use the original alternator. "

____ You could possibly employ BOTH the stock head-lighting system AND-also your choice of such LED-type lighting as well ! ... By simply making use of the alt.power which the stock ign.system wastes (to ground), and rather use that normally wasted power to charge a battery & light your LEDs !



" Does anyone know the actual output of a two-wire alternator? "

____ Well, "actual output" varies accordingly with engine-RPM !
__ However so-long as you don't intend to run a high-power headlight, the stock alt.power should serve your needs fairly well enough, (even without resorting to the use of LEDs).



" I have heard 40W and 70W, "

____ Those wattage-figures are indeed the two factory-alt.ratings for various 450-models, however the R/T-model employs a slightly updated version of the old Motocross 40w.alt.stator.



" I kind of believe 40W especially with what is likely to be weaker than original magnets, so probably even less? "

____ Unless the mag.rotor has been in a fire or dropped & shocked, the magnets should not have been weakened and-thus the alt.power-rating ought-not be significantly reduced from original.


Duke-Cheers,
DCT-Bob

[sjd007]

Thanks for the advice Bob - it has got me thinking! Please excuse my first foray into alternators, I'm no electronic engineer for sure.

I had assumed (considering the two wires were coming out and going into a bridge rectifier) that that was the AC output of the two coils toegther. Are you saying that each of the two coils are (normally) referenced to ground and the two wires are the "hot" wires from each of the coils (ie one for ignition and one for the rest eg lighting).
If that is the case could I bridge the output, run it through the rectifier, drain off any excess voltage with the zener, and run it through a smoothing capacitor to get as many electrons as possible from the 40W alternator? Or am I barking up the wrong tree!

What do you guys do with your two-wire alternator setup? Do you have a proper regulator (mine obviously didn't have all the original parts) so I'm figuring out the best ignition circuit to run to give the best power for lighting. I've got a lot of different widecase single circuit diagrams but none show the two-wire setup.

And one more question - is there an easy way to tell if the wires have been redone at the coil end (ie coils in parallel and fed to the rectifier) or whether the guy I got the bike from had it wrong and had the two leads going to the rectifier when they should have been left one for ignition (as AC / pulses) and one for lighting (which probably didn't need to be rectified anyway, but I want to to run the system on 12V, and use LED's where possible to reduce current drain). I do have a multimeter at least...

Thanks!

Simon

[DewCatTea-Bob]

[quote= sjd007 ...
" I had assumed (considering the two wires were coming out and going into a bridge rectifier) that that was the AC output of the two coils toegther. "

____ While the two separate (internally grounded) power-coils of the stock-alt.stator certainly can't be properly connected-up to a bridge-rectifier (to achieve full-wave rectification), it is possible that someone has connected the (mismatched) coils in 'series' so as to get-by with just the one-pair of alt.wire-leads (for rather proper connection to a bridge-rectifier). _ However that's an inefficient way to attempt to obtain best power-output.
__ It's fairly quite important to determine exactly how the two alt.wire-leads are actually currently connected-up to the alt.stator !



" Are you saying that each of the two coils are (normally) referenced to ground and the two wires are the "hot" wires from each of the coils (ie one for ignition and one for the rest eg lighting). "

____ Yes, you seem-to understand all that correctly, (as concerning a stock-system). ...
The stock alternator setup actually has TWO separate AC.power-sources, each of which is specifically intended for a particular & separate load-system, (as you've already noted) !



" If that is the case could I bridge the output, run it through the rectifier, drain off any excess voltage with the zener, and run it through a smoothing capacitor to get as many electrons as possible from the 40W alternator? "

____ I'm really not very sure of exactly what you may actually mean...
The use of a Zener-diode would tend to curtail getting "as many electrons as possible", as it's dumping-circuit may possibly waste some electron-current to ground) !
Also, (and more pertinently),, are you meaning to ask if you could connect ("bridge") the two power-outputs together, for connection with your single rectifier,
(or what exactly ?) ? _ Do you mean 'with', or 'without', un-grounding the two alt.power-coils ?



" Or am I barking up the wrong tree! "

____ Not-sure yet, (until you've answered the above),, however most-any electrical-configuration could possibly be accomplished, with some kind of reconfiguration of the wiring-scheme.
For instance,, the pre-grounded power-coils would-not pose too-many problem-troubles, if you were to chose to employ the addition of isolated ground-wires (along-with the regular hot/power-wiring).



" What do you guys do with your two-wire alternator setup? "

____ Be careful of who you may ask such a question as that, cuz there's a very-common 2-alt.wire setup that's very-much different than the relatively-rare 2-wire version which the 450R/T employs !
__ So to answer your question,, most-all R/T-owners leave the stock-setup, pretty-much the same as stock.
But if you tell me exactly what you wish for your project electrical-system to be able to do, then I could likely tell you of at-least one suitable option which you could consider.



" Do you have a proper regulator (mine obviously didn't have all the original parts) "

____ The stock R/T didn't have any need for any such power-controllers !
__ If the load-system is pretty-much matched with the available alt.power, then a regulator is little more than dead-weight ! _ Especially when there's such little available electrical-power.



" so I'm figuring out the best ignition circuit to run to give the best power for lighting. "

____ So does that mean you're considering conversion from the stock magneto-type ign.system, to straight-DC.ignition ? _ And do you realize that you'd then need to change the stock AAU ?
__ Anyhow, the stock-ign.system actually does WASTE a good deal of the alternator's power !! _ And while a great portion can possibly be saved,, it would still waste some power, which a straight-DC.system would-not do.



" I've got a lot of different widecase single circuit diagrams but none show the two-wire setup. "

____ I've now posted a pic.diagram of it, here-below for you.



" is there an easy way to tell if the wires have been redone at the coil end "

____ Yes, with an ohm-meter...
With one meter-lead grounded to motor-casing, and the other test-lead connected to EITHER alt.lead-wire,, your meter should read less than 1-ohm (for a stock-setup) !
However if there happens to be no continuity through to ground,, then you might find an ohm-reading of between 1 & 2 ohms, between the two alt.wire-leads, (if somebody has internally ungrounded & connected the two power-coils together [for bridge-rectification] ).



" (ie coils in parallel and fed to the rectifier) "

____ Ya couldn't get-away with directly connecting them in 'parallel', as the ign.power-coil would then see the lighting power-coil as a near short-circuit, (even if the polarities of both coils are properly likewise-matched !) !



" or whether the guy I got the bike from had it wrong and had the two leads going to the rectifier
when they should have been left one for ignition (as AC / pulses) and one for lighting "

____ That's fairly likely,, as many who have a fairly decent handle on electrical-stuff, still fail to completely realize everything they've gotten themselves involved with, (even-though they think they fully understand everything they're working with) !



" I want to to run the system on 12V, and use LED's where possible to reduce current drain). "

____ That's certainly feasible (with a battery-less system),, however, ya may possibly not attain enough voltage build-up to provide any actual charging-current for a 12v.battery, whenever running much below 4000-RPM.


Duke-Cheers,
-Bob

[sjd007]

Thank you, that is the best post ever

I have been looking for the RT wiring diagram for only about a year! 4 Manuals and countless downloads later - I should have signed up to this forum long ago... Yes, if the wiring is stock (and I'll check with my multimeter - that all makes perfect sense to me) I'll leave ignition on one coil and see if the other will be enough for lights (and with an LED tail light, it may flicker at low rpm on AC being a diode, but no harm in plugging it in and seeing what happens!). I hear what you are saying about low output and not really needing to regulate it. Is it worth rectifying it and running a capacitor if flicker is a problem (or battery) to make use of the other half of the wave that the LED's would block? Just to smooth it out and leave a bit of headroom. Anyway, I'm sure this will all become fairly self evident once up and running. I still have some valve shimming and a piston to swap out so don't hold your breath on that, but at least I know which direction to take now with the electrics!

Many thanks again for your detailed and easy to follow explanation, I really appreciate it!

Simon

[DewCatTea-Bob]

[quote= sjd007 ...
" that is the best post ever "

____ But I wasn't even done with it yet, (at the time) !
Seems you were getting your post done, at the same-time as I was finally getting-around buttoning-up my-own. _ So now, it should be even-better to get fully digested.



" I'll leave ignition on one coil and see if the other will be enough for lights "

____ That's just what I would've suggested you try first.
And if you find any need for more power, you could then tap-into the power that's ignored & wasted by the ign.power-coil.



" (and with an LED tail light, it may flicker at low rpm on AC being a diode
Is it worth rectifying it and running a capacitor if flicker is a problem
to make use of the other half of the wave that the LED's would block? Just to smooth it out and leave a bit of headroom. "

____ Full-wave rectification ("to make use of the other half of the wave"), shouldn't be necessary, (considering the very-low power-draw of a LED) ! ... Just rather simple half-wave rectification & a small 100uf-cap should prevent any notable flickering.



" I still have some valve shimming "

____ Have you seen any of the thread-posts which explains why it's not so very important to shim the closing-rockers back-down to the recommended 'zer0' -(.000") closing-clearance ?



" Many thanks again for your detailed and easy to follow explanation, "

____ Of-course you're welcome,, and I thank you as well, for employing your brain-power so as to be able to appreciate my rather detailed post-wording !


Hopeful-Cheers,
-Bob