"Magneto" vs. 'Alternator' , What's the Difference ? ...

[DewCatTea-Bob]

____ For at-least the past couple of years, I've been expecting & awaiting to offer the likes of the following explanation with hopes that someone-else of us here would bring-up the matter of exactly how magnetos & alternators differ,, but no-one has ever directly done-so yet, (and I can't believe that it's because everyone actually KNOWS already). _ And-so since the term 'magneto' has been getting posted rather frequently lately, I've thusly come to realize I ought-to go-ahead & use THAT as motive to finally get this word out-there, (instead of still further waiting).
__ In the past week or so,, there have been significantly more references (than the usual-norm), to the term "magneto", in regards to the electric-power generator setup within the Ducati-models which rather employ Ducati's old straight-AC.powered ignition-system.
In the past, whenever anyone (registered at this w.site) used that word 'magneto' here in the forum (prior to 2012), I'd then always feel the need to correct the use of that term and proclaim that their reference to a "magneto" should ought instead rather be referred-to as an 'alternator' !
The reason for MY-own reasoning that such correction-attempts should be done, is because when I-myself happened to become involved with such workings of motorcycles,, at THAT time, the term 'magneto' had earned a very particular & specific meaning (at-least within the USA) ! ... As such an item was-not merely-just an electrical-generator, but ALSO most of an entire ignition-system all self-contained within just a single component-unit,, and that which some others have referred-to as a 'magneto' within old AC.powered Duc.single-models, is certainly-NOT such as THAT -(multi-component ign.unit) ! _ Thus my-own feeling for the need to point-out the difference (that none of Ducati's alternators are "magnetos"),
(all motivated due-to the related education which my mind had then become conditioned to believe, back from THOSE-days when the term 'magneto' had already rather become actually a nick-name & short-term for a magneto-powered ign.system UNIT [or some-other extended word-line of the like] ).
__ However, just as I had felt I should pass-on my-own (fairly valid) belief of what's-what on this issue,, another fellow (nearly two decades my senior), also felt the need his own-self, to correct ME ! ... And HE then straightened-out ME on what's REALLY what (with the magneto term/definition-issue),, telling me that the ORIGINAL-meaning of what a magneto ACTUALLY is, is that the only difference between a magneto and an alternator, is whether it's the magnet-rotor or the stator-winding which is the moving-part ! _ So ACTUALLY, a real-alternator has stationary magnets with a rotating armature,, while conversely, magnetos have a stationary stator-coil with rotating magnets !
So going by that ORIGINAL definition-description, then ALL our Duke-models really have 'magnetos', (and most all other motorcycles as well) !
BUT yet, these-days,, BOTH true-alternators AND true-magnetos are both called "alternators", and that's what's generally pretty-much universally accepted THESE-days ! _ So that fact somewhat logically leaves the 'magneto' slang-term left to be primarily used as the short-term/nick-name for referring-to any magneto-ign.unit. _ But since the term 'magneto' may still possibly represent either of it's original or slang term-definitions, it seems we're stuck with potential confusion between the two.
__ In any case, one thing is pretty-true though,, the Motocross/Scrambler/Mark-III/n-c.Mark-3/160-models definitely employ magneto-TYPE ignition-systems !


Dukaddy-DUKEs,
-Bob*

(* Note - THIS-post is most-likely to become DCT-ized.)

[Harvey]

Giday Bob good to see you back at your best.
What can I saw, I agree that the term “Magneto” did have a particular meaning that we accepted as ‘that separate unit’, that was added to the engine, to provide the Spark function.
The only other way of providing the spark, was the Kettering system that needs a constant voltage source.

To my understanding, the name Magneto meant, A system that provided the spark, powered by a magnet.
This could be a separate unit, with the magnet, coil, and the switching unit, all in the one block, or the magnet separate from the coil and the switching unit, as most of the small engines, like the Briggs and Stratton, etc are.

“that the ORIGINAL-meaning of what a magneto ACTUALLY is, is that the only difference between a magneto and an alternator, is whether it's the magnet-rotor or the stator-winding which is the moving-part ! _ So ACTUALLY, a real-alternator has stationary magnets with a rotating armature,, while conversely, magnetos have a stationary stator with rotating magnets ! “

Can’t really agree with this wording. An Alternator with either, the magnet or the stator rotating, generates an alternating current, as we use in modern units, that have a rotating magnet.

Cheers Harvey.

[DewCatTea-Bob]

____ Glad to have your input added-in to this thread Harvey !


[quote= Harvey ...
" good to see you back at your best. "

____ But that thread-post actually isn't an example of my "best",, as it hadn't yet been edited -("DCT-ized"), (as indicated right-above my upper posted-picture) !



" I agree that the term “Magneto” did have a particular meaning that we accepted as ‘that separate unit’, that was added to the engine, to provide the Spark function. "

____ Right,, that's what I had learned as fact, back when I became introduced to the world of cycle-engine tech... That a "Magneto" was a self-contained separate unit with not-only all the parts related to a complete spark-producing ign.system, but ALSO included it's very-own dedicated 'magneto' for providing it's very-own electric-power source, to-boot ! _ Thus the single word 'magneto' came-to represent such an ign.system-unit.
However, that's where the confusion arises from,, as once that sort-term became slang for such a single multi-part unit, that slang-term magneto-name then became confusable with a mere (real) magneto -(type of alternator). _ And others like myself had never learned that a real 'magneto' was merely-just a type of alternator (which was constructed to have it's magnets rotate around it's stator).



" To my understanding, the name Magneto meant, A system that provided the spark, powered by a magnet. "

____ Again,, right, (as a self-contained system)... that was also my-own only understanding of that name/term, (which is why I'd always feel the need to correct others whenever they'd use the word 'magneto' instead of 'alternator', even in reference to the alternator on the AC.powered Duke-models).
__ However a couple years back, I was then finally advised that people who called alternators a 'magneto', were actually CORRECT ! _ And-so it really wasn't necessarily always right for me to correct people who used that word instead of 'alternator'.
Having doubted the source who had advised me, I then thoroughly surfed-through the internet and found much to support his claim, (which I admit didn't make me too happy !).



" This could be a separate unit, with the magnet, coil, and the switching unit, all in the one block, "

____ Once-again,, right ! _ By-now, it should be clear that my long-understood (and previous) understanding of what a 'magneto' is, is such a compiled batch of all the otherwise separate ign.parts required for a complete ign.system, ALL contained in just one block-unit, (as like that which I've posted a picture showing 3 or 4 of).


" or the magnet separate from the coil and the switching unit, as most of the small engines, like the Briggs and Stratton, etc are. "

____ THIS chosen-wording of yours, fairly-clearly seems to indicate that a 'magneto' may ALSO be just a mere collection of all the same ign.parts, BUT-however WITHOUT them all being held/contained within a single block-unit. ...
That rather loose definition for a 'magneto', I-myself have never heard-of, and can't really agree with !
__ But however, I have already agreed that such a set of separately-located magneto-ign.system parts, ought be referred-to as a magneto-TYPE ignition-system, (like as employed by the old Duke-models with Ducati's AC.powered electrical-systems).
Cuz it surely doesn't seem properly-correct to call a bunch of separate ign.parts that are all spread-out all-over various locations on the frame & motor, as simply a 'magneto' !

“ that the ORIGINAL-meaning of what a magneto ACTUALLY is, is that the only difference between a magneto and an alternator, is whether it's the magnet-rotor or the stator-winding which is the moving-part ! _ So ACTUALLY, a real-alternator has stationary magnets with a rotating armature,, while conversely, magnetos have a stationary stator with rotating magnets ! “

Can’t really agree with this wording.

____ Yeah, that's some fairly sparse wording which I had thought I might try restating in other-words, later-on sometime.
While it pretty-much says what I had meant to convey, I suppose you possibly could've taken-it in some way which I hadn't really meant.
I'll now try to put what I had meant to state in other-words, following next...
__ Concerning the name-term 'MAGNETO', as it was originally coined,, that word's ORIGINAL-meaning was only meant to merely represent a type of alternator which has a stationary stator-winding & a ROTATING permanent-magnet/rotor-flywheel.
Where-as, conversely,, concerning the name-term 'ALTERNATOR', as it was originally coined,, that word's ORIGINAL-meaning was only meant to merely represent a type of electric-power generator which has a rotating armature-rotor & a STATIONARY permanent-magnet.
__ Now does this-above new/re-wording solve your particular issue with my quoted-wording, or does your issue still remain ?



" An Alternator with either, the magnet or the stator rotating, generates an alternating current, as we use in modern units, that have a rotating magnet. "

____ Right again, of-course ! ... And that statement isn't at-all at odds with my originally-stated/quoted-wording. _ So if your last statement was meant to-be any at-all contradictory to that quoted-wording of mine, then it seems that you really had indeed actually taken-it with a rather wrong interpretation.


Dukaddy-DUKEs,
-Bob

[Harvey]

Well Bob I think we are trying to define what the words “Magneto, and Alternator” mean, rather than defining what the functions of the units are.
The Alternator is a generator that generates an alternating current. Used for lights, and rectified, to charge batteries.
It doesn’t matter if the magnet or the windings rotate; the end result is Alternating current.

The Magneto, regardless if the magnet is stationary like the older BTH or Lucas, or rotating like the Ducati, they all use a rising power pulse, to generate the energy for the coil, to convert for the spark. It doesn’t use AC to do it, so it is completely different to the Alternator in this respect.

If we are looking at a unit like the Ducati system, we have a combination of functions. Most of the coil windings are used to producing an AC current for lighting, but one coil is dedicated to producing the pulse, for the Magneto ignition system.
As the magnet starts to move across this coil, the current starts to build up flowing around, through the closed points. If the flywheel is fitted in the right position (as you always rightly point out), the magnet will be at its strongest position above the coil, and the current flowing through the points will be at its highest, with the piston at
27* BTDC ?
The points open, and the current is forced to flow through the coil primary. Because the DC resistance, and the Impedance of the circuit have risen, the current reduces, and the voltage rises, to produce the very fast rising flux, that produces the spark.

So what we have in the Ducati type system is, a combined AC generator, and a Magneto Ignition system. So people will call it either, or both, it will always be confused.

[DewCatTea-Bob]

[quote= Harvey ...
" I think we are trying to define what the words “Magneto, and Alternator” mean, rather than defining what the functions of the units are. "

____ Well ACTUALLY,, the intended-purpose of this-thread which I've posted, is to cover BOTH of those aspects, so-as to clear-up what's-what on this topic !
__ From the main-jest & bottom-line of YOUR most-recent post,, it seems that you may-not have fully realized my intended MAIN-point which my posts have actually meant to convey, and-also probably haven't yet bothered to search the net to confirm exactly what the consensus is for the prime-meaning of the word 'magneto'.
__ Proceeding-onward .....



" The Alternator is a generator that generates an alternating current. Used for lights, and rectified, to charge batteries.
It doesn’t matter if the magnet or the windings rotate; the end result is Alternating current. "

____ Well (although rather basic), of-course that's mostly-all quite fairly correct, at-least accordingly in THESE-days, of more modern-times !
HOWEVER, back before most of us here were born, back when alternators were then relatively NEW-technology,, a TRUE-magneto merely-just performed ONLY all the very-SAME as you've proclaimed-above for an 'alternator',, except the only difference IS, is that a true 'alternator' has stationary magnets, while a 'magneto' has ROTATING magnets !! _ Otherwise, the two power-generating devices are exactly the SAME in functionality ! ...
__ Please try to realize that I've been meaning to indicate that this WAS the correct-understanding, ORIGINALLY, (back in days gone-by !), way-back before the invention of a self-contained magneto-powered energy-transfer ignition-system all-in-one unit,, which we 'TODAY' now have come to refer-to simplifiedly as a "magneto" (in a rather developed slang-word usage manor) !
So the newer-term "magneto" was high-jacked (or perhaps rather outright stolen) from the older definition which it had ORIGINALLY once solely owned ! _ And-so the newer slang-version/short-term name of 'magneto' has BECOME the (rather new) accepted name for a complete ET.ignition-system that's entirely contained within it's-own container-unit along-with it's very-own power-generator.
So now that the usage of the word 'magneto' has since become so much more popularly used in this newer fashion, we've thusly come to understand the word 'magneto' as meaning what it has come to mean to you & I, THESE-days.



" The Magneto, regardless if the magnet is stationary like the older BTH or Lucas, or rotating like the Ducati, they all use a rising power pulse, to generate the energy for the coil, to convert for the spark. It doesn’t use AC to do it, so it is completely different to the Alternator in this respect. "

____ Well yes, of-course,, as is referred-to by the later-acquired definition appropriated to represent the new-meaning for the commandeered word "Magneto".
__ Quite apparently your mind-conditioned understanding of what a magneto is, is just the same as my-own once WAS !
I first didn't want to believe what I was informed of concerning the original-meaning for the word 'magneto', myself either ! _ But I then checked-through the internet and came to realize what the general-consensus is for the original-meaning of the word 'magneto', and became converted to realize the actual-truth.



" If we are looking at a unit like the Ducati system, we have a combination of functions. Most of the coil windings are used to producing an AC current for lighting, but one coil is dedicated to producing the pulse, for the Magneto ignition system.
As the magnet starts to move across this coil, the current starts to build up flowing around, through the closed points. If the flywheel is fitted in the right position (as you always rightly point out), the magnet will be at its strongest position above the coil, and the current flowing through the points will be at its highest, with the piston at
27* BTDC ?
The points open, and the current is forced to flow through the coil primary. Because the DC resistance, and the Impedance of the circuit have risen, the current reduces, and the voltage rises, to produce the very fast rising flux, that produces the spark. "

____ Yes,yes, all quite true,, and we've already gone-through all those intricaticities once before in another past thread. _ But that related-stuff is pretty-much off-track to what's been meant to be covered within THIS thread. ...
I'm mostly just trying to get us informed as to WHY we have confusion over the word 'magneto', and what's different between magnetos & alternators (and-also between those two power-generators & magneto-powered ign.units).



" So what we have in the Ducati type system is, a combined AC generator, and a Magneto Ignition system. "

____ Yes... In respect to the energy-transfer ign.systems (employed with Ducati's AC.powered electrical-systems),, they employ (half of) a Ducati 'alternator', (which was originally called a "magneto", in the distant-past). _ And-so thus emulate a magneto-type ign.system, (which should really be called an ET.ignition-system, instead of a "magneto" !).



" So people will call it either, or both, it will always be confused. "

____ It certainly seems that you've got that RIGHT !



____ So I guess the bottom-line here for THESE-days, is that yesteryear's 'alternator' and 'magneto' as-well, have both now become called ALTERNATORs,, and yesterday's self-contained magneto-powered ET.ignition-system has taken-over the term 'magneto' .


Dukaddy-DUKEs,
DCT-Bob