six coil alternator in a narrow case 250

[ecurbruce]

This is my first post, though I've been following several subjects for a couple of years.

Would there be any use for a six pole-six coil alternator in my '65 monza 250 narrow case? Well I thought so, I'm the kind of guy who likes lots of power,and I'll find a way to put it to use. Has anyone tried this?
So here it is...This is actually a narrow case type six lug four coil alternator, with two added coils from another doner alternator of the narrow case variety.

Here's how it's done... from a doner six lug four coil alt. the last two coil pax are removed by- unsolder the four wires from each coil, notice how they are wired for future use rewiring. There is a copper retainer shim with a 90 degree bend at the end, between the steel lug and the plastic housing of each coil. Flatten out the 90 degree bend, to allow the plastic housing to slide off the end of the steel lug. After removing the two coils, put the 90 degree bend back in the copper shims and place them in the plastic housings. Notice there is a tab in the copper shim that locks into a hole in the steel lug. Slide the removed coils onto the empty lugs of the alternator being used, paying attention to the order of large and small coils. Here is where it gets tricky... with the coils in place, the alternator won't bolt into the engine case.
With copper shims in place, get the coils just barely started on the steel lugs, then bolt into the engine case.

alternator install.JPG

With alternator installed, the coils can now be slid down into place until the locking tabs catch. This can carefully done with a 1" putty knife against the top of plastic housing, and channel lock pliers against the putty knife and oposite steel lug, and carefully squeeze. When in place, resolder wire leads in series with existing coils.
The polarity of the coils can be checked by energizing the coils with a 6 volt lantern battery, and a compass placed at the end of the steel lugs. Each lug should out of phase with the one next to it. Also each of the two circuits should be out of phase with eachother.
This will give the output of a wide case alternator in a narrow case engine.

6_coil_alt.JPG

[Bevel bob]

Neat, and inexpensve,can the process be reversed when its time to replace the main bearings?, many of us are numbnuts with electrics and your instructions on wiring and phase checking did not penetrate the fog, a close up photo would help.The additional output would be most usefull.

[ecurbruce]

[quote="Bevel bob"]Neat, and inexpensve,can the process be reversed when its time to replace the main bearings?]
Sure, any of the coils can be removed by bending the retaining shim down, unsolder, and slide right off.(with the exception of the one with the external wires attached, there's not room before it hits the motor case.) The entire process could also be done with the crank in, though it would be a little more crowded.

[DewCatTea-Bob]

By: ecurbruce...
" Would there be any use for a six pole-six coil alternator in my '65 monza 250 narrow case? "

____ Unless you've considerably increased your elect.system's load, there really shouldn't be any worth-while use for such modification !


" Has anyone tried this? "

____ I-myself once wanted to try filling all 6 stator-pole/lugs with coils, but then abandoned the notion as I didn't care enough (as you have) to figure-out a way to retain the stator-plate to the (n-c type) motor-case. - (I think fellow-member wcorey may have come-up with a stator-plate adapter for possibly addressing this fitment-issue.)


" The polarity of the coils can be checked by energizing the coils with a 6 volt lantern battery, and a compass placed at the end of the steel lugs. Each lug should out of phase with the one next to it. "

____ That you came-up with a method to double-check for proper polarities of the two added pairs of windings, indicates that you're indeed aware of the complexities of your alt.modification work ! - (And someone-else who's not so clearly understanding of the required arrangements, could possibly cause their alternator to become half as strong rather than 50% stronger than stock.)


" This will give the output of a wide case alternator in a narrow case engine. "

____ So it would seem ! _ However, you have not specified whether or not you keep your amped-up alternator wired-up (to the twin wire-lead alt.cable) just like stock, and still left connected-up to the stock half-wave rectifier-box !?
Cuz if so, then this method for obtaining increased charging-power is certainly the most difficult method for going-about getting such !


____ It's always quite interesting to learn of what others have come-up with to modify their electrical-systems !
So thanks extra-much for your very unique alt.modification-report !


Alternate-Cheers,
-Bob

[ecurbruce]

"whether you keep your amped-up alternator wired as stock and still connected-up to the stock half wave rectifier box?"

In my particular case, it is 12 volt I guess what you'd call single phase through a series type voltage regulator to run street gear including a zenon headlamp from a BMW automobile,
however this could be wired in any of the ways you've described in your other threads on 6 volt or 12 volt schemes. This just gives more of a good thing. I know not every one wants more, though.

[DewCatTea-Bob]

" In my particular case, it is 12 volt I guess what you'd call single phase through a series type voltage regulator "

____ Okay then, so it now seems that you don't have the twin wire-leads of the stock alternator still wired-up to a stock black-box... But then since it seems that you currently have your modified-alt connected to a generic-type 12v.reg/rect-unit, the question then diverts to the manor in which your 12v.R/R-unit is able to make use of what it's fed by your modified-alt...
__ For example, if your 12v.R/R-unit is the standard/ordinary single-phase type which FULL-wave rectifies the alt.output from a single-pair of alt.wire-leads, then in order to have that unit's negative-output normally-grounded, you'd then be required to have the stock alt.stator ground-connection UN-grounded ! _ An important detail which you haven't covered, not only in your otherwise extensive report-post, but also left-out of your response-post which ought to have by then covered that oversight -(which I've been meaning for you to cover & get cleared-up).
__ On the other-hand, if that stock alt.winding-lead ground-connection was intentionally left pretty-much just as stock, then in order for your chosen 12v.R/R-unit to work properly with your still stockly-connected (but 6-coil) n-c alternator, your particular 12v.R/R-unit MUST then be a dual half-wave rectifier type, like stock (which is fairly doubtful) ! _ Which in-turn would then mean that your resulting charging-system is thus ignoring half of the charging-power available from the alternator (just like stock) !
__ I've since downloaded & expanded your pictures for a better look-see at them but, unfortunately they're then a bit blurry and I'm thus still not sure of what I'm actually seeing... But it seems I can see a soldered ground-connection, (please correct me if I'm wrong), at about 4-o'clock near the crankshaft-hole. _ And if that's the alt.stator ground-connection I'm thinking it is, then certainly a more detailed explanation of your charging-system's working-plan is in due order !
__ Hope you can explain how your charging-system is intended to function properly, in either case.
And if you can't, then please also tell me all you can about your chosen 12v.R/R-unit, and hopefully I'll then be able to explain what your particular charging set-up is actually doing !


" to run street gear including a zenon headlamp "

____ Can you tell us how much current one of those lights consume ?


Hopeful-Cheers,
-Bob

[ecurbruce]

Thanks for your valued input, every little bit helps. Yes, my photos show end leads grounded, but I've all but abandonded that idea in favor of isolated ground and a third wire out. Not sure just where that lead will end up, I have a couple of options, I'm still playing with that part of the puzzle. I'm open to recomendations, keeping in mind this will be a regulated system.
About the regulator... I should not have said "single phase" regarding my system, this regulator rated 12 volt, I believe a bridged rectifier, series style circuitry. It has 2 AC in and a battery + terminal.
I'm thinking one of the designs for the wide case alternator is going to work. Whatever the outcome, it will come from 6 coils instead of four.

____"Can you tell us how much current one of those lights consume?"

The zenon pulls 5.5 amps @ 12.5 volts, a halogen pulls about 4.7 amps. May or may not be suitable, we'll see when it"s all said and done...

[DewCatTea-Bob]

" Yes, my photos show end leads grounded, but I've all but abandonded that idea in favor of isolated ground and a third wire out. "

____ Alright, in order to FULL-wave rectify (both positive & negative power-pulses of both alt.windings of) the entire alternator's power-output, those two alt.winding lead-ends must be UN-grounded !
I-myself would then hook-up a 4 wire-lead alt.cable (rather than an alt.cable with just 2 or 3 conductor-leads), but all that's really needed for a regulated system which will always run with lights left ON, is a twin wire-lead alt.cable.


" Not sure just where that lead will end up, I have a couple of options, I'm still playing with that part of the puzzle. "

____ Rather than simply connecting & isolating the (normally grounded) alt.winding lead-ends, (as others have done),, a 3rd/added wire-lead within your alt.cable will allow for more useful options, (such as possibly making use of a stock 12v.R/R-box from a bevel.L-twin).


" I'm open to recomendations, keeping in mind this will be a regulated system. "

____ If your Duke will still have a lights-On/Off-switch, then your voltage-regulator's life may be rough if you run at high-revs without lights turned-on... So in that case, the third wire-lead could be of certain use.


" About the regulator... I should not have said "single phase" regarding my system, this regulator rated 12 volt, I believe a bridged rectifier, series style circuitry. It has 2 AC in and a battery + terminal. "

____ Alright then, I gather that it has only two wires for AC-input (which indicates that it is indeed a 'single-phase' type), and a terminal that's intended for it's positive-output, thus meaning that it probably has a negative-grounded metal-case (for passing it's negative-output through). _ I say "probably" because I'm still not sure what this unit of yours was intended to be used for, as it's description leaves it a possibility of having been made to work with a stock Monza type charging-system (since it may not actually have a negative-output) !
But if we continue to assume that it really was made for connection to an ungrounded alternator-circuit, then it would no-doubt employ a full-wave/bridge rectifier.


" I'm thinking one of the designs for the wide case alternator is going to work. "

____ With the mods it now seems you intend to make, you will then be able to use any system that a (stock) wide-case alternator could work with !


" The zenon pulls 5.5 amps @ 12.5 volts, a halogen pulls about 4.7 amps. "

____ That's somewhat disappointing, as I was hoping for a bit less rather than more power-consumption.
Do you also have specs for comparing light-output?


Hopeful-Cheers,
-Bob

[jbcollier]

One of the limitations of the stock coils is the fact that wire used is quite small in diameter. The advantage of going to six coils is that you can have thicker wire and still have a similar wind count. Here's what I did:

http://s250.photobucket.com/albums/gg26 ... CN1250.jpg

[DewCatTea-Bob]

" One of the limitations of the stock coils is the fact that wire used is quite small in diameter.
The advantage of going to six coils is that you can have thicker wire and still have a similar wind count. "

____ My understanding of your wording is that you've traded-off & downed the number of coil-winding loop-turns per power-coil, in exchange for filling-up the same amount of volume-space with fewer loop-turns of a THICKER-gauge of wire-windings, since you now have an additional pair of power-coils to hold an extended-length stator-winding.
That makes particularly reasonable sense to me if intended for a higher-current / lower-voltage charging-system. _ (Compared to a 6-coil/6-pole alt.stator with a greater number of coil-loops of a thinner gauge.)
That approach to alternator-modification, doesn't really allow the extra pair of power-coils to produce much ADDITIONAL power, but the effect of the thicker-gauge stator-winding DOES allow the alt.winding to pass-on it's power to the load-system more efficiently.
__ So can you report how the fewer number of windings (per core-coil) effected voltage-output, especially at the lower RPM range where it's more of a concern ?
Cuz without supporting data, I'd be inclined to assume that the thicker gauge windings (without any notable increase of total coil-loops, around all 6 poles), would be a modification (over the stock 4-coil alt.stator), which would merely better serve to keep a much larger 6-volt battery charged-up.


Hopeful-Cheers,
-Bob