Today's Message Index:
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1. 06:50 AM - Re: Re: Revmaster 'dual' alterantors (Robert L. Nuckolls, III)
2. 08:25 AM - Re: Re: Revmaster 'dual' alterantors (Robert L. Nuckolls, III)
3. 08:32 AM - Re: Re: AV 30 Wiring (Robert L. Nuckolls, III)
4. 09:42 AM - Re: Revmaster 'dual' alterantors (dj_theis)
5. 10:12 AM - Re: Revmaster 'dual' alterantors (user9253)
6. 11:47 AM - Z101 RevB (FRANK MCDONALD)
7. 12:33 PM - Re: Z101 RevB (Werner Schneider)
8. 01:23 PM - Re: Re: Revmaster 'dual' alterantors (Paul Eckenroth)
9. 01:50 PM - Re: Revmaster 'dual' alterantors (dj_theis)
10. 02:21 PM - Re: Re: Revmaster 'dual' alterantors (Robert L. Nuckolls, III)
11. 03:01 PM - Re: Z101 RevB (frank3)
12. 04:30 PM - Re: Re: Revmaster 'dual' alterantors (Paul Eckenroth)
Message 1
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| Subject: | Re: Revmaster 'dual' alterantors |
At 08:43 AM 9/9/2020, you wrote:
>I think that there might be a misunderstanding of the Revmaster
>architecture in that I don't believe that the windings for the
>two generators are in tandem but are a series of 5 coils each
>for two generators.
Hmmmm . . . if that's the case, then it's probably
accurate to call it a 'dual' alternator system . . .
or perhaps 1/2 + 1/2 alternators system.
The energy generation potential for these alternators
is a function of the magnetics/mechanics. Magnet
strength, magnetic cross-section of the stator
and rotor, permeability of the steels, air gaps
between moving parts, rates of change for
magnetic lines of force acting on the windings (rpm)
and a few other little details like losses in
the steels and windings.
Bottom line is that by dividing the two windings
between stator 'halves', the ability to do
the mechanical to electrical energy conversion
for each alternator is about 1/2 that of the
potential whole.
It would seem more practical to have all
the stator magnetics to participate in the
energy conversion efforts using fewer turns
per pole of heavier wire. One might then
achieve more robustness and more energy
output at the same time.
> I have enclosed a picture of the stator from my friend's engine.
I don't see that image . . . how did you 'enclose'
it?
>It seems to me that the most important change will be to use the B&C AVC1
>volltage regulator since it is designed for firewall forward and can be
>adjusted down to 13.7 v which is the minimum voltage that will fully charge
>the EarthX battery. With the voltage reduction should come current reduction.
Probably not. Keep in mind that as you rotate of the
runway into the blue, there are two kinds of loads
on your alternator. Battery recharge + system running
loads. The TOTAL of these two values is exceeding
the alternator's limitations for thermal management
and has not much to do with the bus voltage set-point.
The fact that an EarthX battery seems to exacerbate
the failure rate only speaks to that battery's
lower internal resistance and willingness to accept
charge at a lower voltage than SLVA.
I.e. the LiFEPO4 battery is NOT ROOT CAUSE of the
unhappy condition . . . only a slightly greater
stress on the alternator seems to exacerbate
failure rates. Adjusting the voltage down by
exploiting the features of the AVC1 might
reduce the failure rate but I kinda doubt it.
I've got a fully discharged ETX36D on the bench
that I'll try to plot the recharge profile when
impressed with a 13.7V set-point. But I'm
confident that an adjustable regulator will not
'fix' fundamental shortcomings of the alternator.
>What I don't know (and hopefully the educated on the list can explain)
>is whether restricting the voltage will also restrict the current.
Maybe a little
>Can the generator still create abnormal current and therefore heat.
You betcha . . . but system loads are much more
significant than characteristics of the battery.
>I will try and incorporate thermocouples in with the coils but I'm
>not sure how much advance warning they can give.
Lots of warning. Those wires don't smoke in tens
of milliseconds like fuses. The insulation degrades
over time . . . probably hours of operation at
temperatures exceeding design limits of the INSULATION.
I think this system would benefit greatly by some
extensive testing on a drive stand to optimize
wire size and turns against instrumented performance
measurements. The SD8 from B&C got tested with about
a half dozen exploratory configurations before the
final configuration went to production.
I'd like to see the performance characteristics
of the existing stator wound with fewer turns
of fatter wires on ALL available energy
production poles.
Bob . . .
Message 2
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| Subject: | Re: Revmaster 'dual' alterantors |
At 05:25 PM 9/9/2020, you wrote:
>Well, for $500 you could rewind the stator by hand, and use a
>heavier gauge wire.
THAT would be a really good experiment!
Bob . . .
Message 3
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| Subject: | Re: AV 30 Wiring |
At 04:28 PM 9/9/2020, you wrote:
>
>I would agree. On the second drawing, the only place TPS is shown
>is on those wires with the "X".
>
>Although it does appear the shields are grounded in two places. I
>thought the idea was to always ground the shield at one end.
Yes . . . but.
If the design goal for shielding wires
is to BREAK and electro-static coupling
mode between potential antagonist/victim
wires, then yes . . . connect shield to
one ground only.
SOME installations exploit the shield as
part of the energy management goal. One
example can be seen in the Z-figures where
I recommend GROUNDING a p-lead shield at
the magneto end then using the shield
to provide a GROUND PATH for the switch
at the other end. Some authors have
suggested that p-leads need to be shield
grounded at BOTH ends which has no foundation
in physics and raises risks for some ground
loop issues.
I've also used the shield as a return
path for incandescent bulbs illuminating
a whisky compass. Providing a coaxially
concentric out-and-back path for bulb
currents cancels magnetic fields around
the wire and prevents illumination induced
heading errors.
The best thing to do is follow the
manufacturer's installation instructions.
I cannot assert they are always 'golden'
but there just might be a good reason
for doubling up shield terminations.
Bob . . .
Message 4
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| Subject: | Re: Revmaster 'dual' alterantors |
nuckolls.bob(at)aeroelect wrote:
> At 08:43 AM 9/9/2020, you wrote:
>
> > I think that there might be a misunderstanding of the Revmaster
> > architecture in that I don't believe that the windings for the
> > two generators are in tandem but are a series of 5 coils each
> > for two generators.
>
> Hmmmm . . . if that's the case, then it's probably
> accurate to call it a 'dual' alternator system . . .
> or perhaps 1/2 + 1/2 alternators system.
>
>
>
> > I have enclosed a picture of the stator from my friend's engine.
>
> I don't see that image . . . how did you 'enclose'
> it?
>
>
Images as attachments of the R2300 from when I first received my engine in 2017.
There are two separate stator windings, 5 coils on each stator with relatively
large wires (12 AWG ?). Next time I pull the engine, I'll mic the wires on the
coils.
Note, setting this up as a center tap as suggested should be straight forward.
Again I have to state that I think the average current with your center tap arrangement
will be the same as the OEM half wave R/R with both sides enabled.
>
> I think this system would benefit greatly by some
> extensive testing on a drive stand to optimize
> wire size and turns against instrumented performance
> measurements. The SD8 from B&C got tested with about
> a half dozen exploratory configurations before the
> final configuration went to production.
>
> I'd like to see the performance characteristics
> of the existing stator wound with fewer turns
> of fatter wires on ALL available energy
> production poles.
>
>
>
> Bob . . .
I will try to obtain some fundamental characteristics of the alternators within
the next 30 days. (i.e. short circuit current, open circuit voltage at starter
rpm, inductance...).
Let me point out the obvious,... "redesigning this system puts the builder in a
situation of complete ownership of the problem as it is doubtful Revmaster will
support a modified system." The OBAM pilot takes on that responsibility (or
should he/she does) regardless of the OEM support, so maybe that is not worth
mentioning.
Adding an external alternator is not obvious (to me) where it would mount but
earlier versions of the engine had external alternators (I believe), so the design
components could be available Revmaster. I amazed (concerned) that with
the close proximity of the CDI power coils and ignition electronics that there
are no reported failures of that system, related to the alternator failures.
makes me want to consider returning to 2 mags and an external alternator for
the R2300. Again, maybe easier said the executed but certainly a design that
was once available.
One thing that puzzles me though. At least one failure of BOTH alternators, as
reported by Eric or Paul, occurred with only one alternator activated. How is
it possible to overheat both sides simultaneously (through heat conduction I
have to assume) without damaging the ingnition coils that sit between the two
alternators ??
(Molex connectors and wires in my photo from the two ignition coils and the timing
signals are shown).
I have to suspect there is another heat source or cause that is contributing to
these PMA failures. Engine heat?
Dan Theis
--------
Scratch building Sonex #1362
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498299#498299
Attachments:
http://forums.matronics.com//files/20200910_154510000_ios_107.jpg
http://forums.matronics.com//files/20200910_152443000_ios_116.jpg
Message 5
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| Subject: | Re: Revmaster 'dual' alterantors |
There are 4 black screws in the picture that look like they might hold a cover
on. Is it possible to pipe pressurized air into that cover to cool the coils?
If the coils were kept cool, their ampacity would be greatly increased.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498300#498300
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Is there a way to get a simple pdf version of the newest revision of Z101? I am
not a CAD person, though I admire those that are.
Thanks much.
Frank
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Yes Frank
http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/
there you find all as PDF's
On 10.09.2020 20:42, FRANK MCDONALD wrote:
> Is there a way to get a simple pdf version of the newest revision of
> Z101? I am not a CAD person, though I admire those that are.
> Thanks much.
> Frank
Message 8
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| Subject: | Re: Revmaster 'dual' alterantors |
Hopefully here is the image of the stator that I thought was sent
previously.
Paul
On Thu, Sep 10, 2020 at 12:51 PM dj_theis <djtheis58@gmail.com> wrote:
>
>
> nuckolls.bob(at)aeroelect wrote:
> > At 08:43 AM 9/9/2020, you wrote:
> >
> > > I think that there might be a misunderstanding of the Revmaster
> > > architecture in that I don't believe that the windings for the
> > > two generators are in tandem but are a series of 5 coils each
> > > for two generators.
> >
> > Hmmmm . . . if that's the case, then it's probably
> > accurate to call it a 'dual' alternator system . . .
> > or perhaps 1/2 + 1/2 alternators system.
> >
> >
> >
> > > I have enclosed a picture of the stator from my friend's engine.
> >
> > I don't see that image . . . how did you 'enclose'
> > it?
> >
> >
>
>
> Images as attachments of the R2300 from when I first received my engine in
> 2017.
> There are two separate stator windings, 5 coils on each stator with
> relatively large wires (12 AWG ?). Next time I pull the engine, I'll mic
> the wires on the coils.
> Note, setting this up as a center tap as suggested should be straight
> forward. Again I have to state that I think the average current with your
> center tap arrangement will be the same as the OEM half wave R/R with both
> sides enabled.
>
>
> >
> > I think this system would benefit greatly by some
> > extensive testing on a drive stand to optimize
> > wire size and turns against instrumented performance
> > measurements. The SD8 from B&C got tested with about
> > a half dozen exploratory configurations before the
> > final configuration went to production.
> >
> > I'd like to see the performance characteristics
> > of the existing stator wound with fewer turns
> > of fatter wires on ALL available energy
> > production poles.
> >
> >
> >
> > Bob . . .
>
>
> I will try to obtain some fundamental characteristics of the alternators
> within the next 30 days. (i.e. short circuit current, open circuit voltage
> at starter rpm, inductance...).
>
> Let me point out the obvious,... "redesigning this system puts the builder
> in a situation of complete ownership of the problem as it is doubtful
> Revmaster will support a modified system." The OBAM pilot takes on that
> responsibility (or should he/she does) regardless of the OEM support, so
> maybe that is not worth mentioning.
>
> Adding an external alternator is not obvious (to me) where it would
> mount but earlier versions of the engine had external alternators (I
> believe), so the design components could be available Revmaster. I amazed
> (concerned) that with the close proximity of the CDI power coils and
> ignition electronics that there are no reported failures of that system,
> related to the alternator failures. makes me want to consider returning to
> 2 mags and an external alternator for the R2300. Again, maybe easier said
> the executed but certainly a design that was once available.
>
> One thing that puzzles me though. At least one failure of BOTH
> alternators, as reported by Eric or Paul, occurred with only one alternator
> activated. How is it possible to overheat both sides simultaneously
> (through heat conduction I have to assume) without damaging the ingnition
> coils that sit between the two alternators ??
>
> (Molex connectors and wires in my photo from the two ignition coils and
> the timing signals are shown).
>
> I have to suspect there is another heat source or cause that is
> contributing to these PMA failures. Engine heat?
>
> Dan Theis
>
> --------
> Scratch building Sonex #1362
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=498299#498299
>
>
> Attachments:
>
> http://forums.matronics.com//files/20200910_154510000_ios_107.jpg
> http://forums.matronics.com//files/20200910_152443000_ios_116.jpg
>
>
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| Subject: | Re: Revmaster 'dual' alterantors |
user9253 wrote:
> There are 4 black screws in the picture that look like they might hold a cover
> on. Is it possible to pipe pressurized air into that cover to cool the coils?
> If the coils were kept cool, their ampacity would be greatly increased.
It is possible and I agree it's worth considering. I'll look at the CDI eletronics
casting (which is what those screws hold in place) to see if there is a
pathway to generate an inlet and egress for air. I don't have any good photos
of the inside of that casting. Maybe I can pull that casting off without pulling
the engine. I'll look tonight.
Thanks for the suggestion.
Dan Theis
--------
Scratch building Sonex #1362
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498307#498307
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| Subject: | Re: Revmaster 'dual' alterantors |
At 03:18 PM 9/10/2020, you wrote:
>Hopefully here is the image of the stator that I thought was sent previously.
>
>Paul
Excellent . . . thank you. I agree, this definitely
appears to be a PAIR of 5-pole alternators.
Good data point.
Bob . . .
Message 11
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Thanks very much.
Frank
--------
Frank McDonald
Kitfox S7
912S, Sensenich Composite 3 Blade
Acworth, GA
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498309#498309
Message 12
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| Subject: | Re: Revmaster 'dual' alterantors |
Dan
I'll try and get a picture of that casting for you.
Paul
On Thu, Sep 10, 2020 at 4:54 PM dj_theis <djtheis58@gmail.com> wrote:
>
>
> user9253 wrote:
> > There are 4 black screws in the picture that look like they might hold a
> cover
> > on. Is it possible to pipe pressurized air into that cover to cool the
> coils?
> > If the coils were kept cool, their ampacity would be greatly increased.
>
>
> It is possible and I agree it's worth considering. I'll look at the CDI
> eletronics casting (which is what those screws hold in place) to see if
> there is a pathway to generate an inlet and egress for air. I don't have
> any good photos of the inside of that casting. Maybe I can pull that
> casting off without pulling the engine. I'll look tonight.
>
> Thanks for the suggestion.
>
> Dan Theis
>
> --------
> Scratch building Sonex #1362
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=498307#498307
>
>
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