Today's Message Index:
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1. 09:08 AM - Re: Schematic for twin PM alternators (user9253)
2. 09:35 AM - Re: Re: Schematic for twin PM alternators (Robert L. Nuckolls, III)
3. 10:53 AM - Re: Re: Schematic for twin PM alternators (Paul Eckenroth)
4. 11:38 AM - Re: Schematic for twin PM alternators (user9253)
5. 12:50 PM - Re: Re: Schematic for twin PM alternators (Paul Eckenroth)
6. 02:27 PM - Re: Re: Schematic for twin PM alternators (Charlie England)
7. 02:27 PM - AEC 12A z diagrams cropped?? (Charlie England)
8. 02:27 PM - Re: Re: Schematic for twin PM alternators (Charlie England)
9. 02:55 PM - Re: Schematic for twin PM alternators (user9253)
10. 08:07 PM - Re: Re: Schematic for twin PM alternators (ashleysc@broadstripe.net)
11. 09:31 PM - Re: Re: Schematic for twin PM alternators (Charlie England)
12. 11:36 PM - Re: Schematic for twin PM alternators (user9253)
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| Subject: | Re: Schematic for twin PM alternators |
Interesting blog about connecting home generators in parallel:
http://yarchive.net/car/rv/generator_synchronization.html
Most of the cautions and concerns described in that blog do not
apply to the Revmaster alternator because the relative speed
(frequency & voltage) and phase angle between the two windings
never changes, due to the common permanent-magnet field.
Before connecting the Revmaster alternator windings in parallel, it must be determined
that the two windings are in phase and not out of phase.
The blog describes how to do that.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452026#452026
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| Subject: | Re: Schematic for twin PM alternators |
> I will suggest that studying anything published
> in the 'Connection will be of limited value
> until we understand exactly what's installed
> on the engine and how the manufacturer intended
> that it be used.
All creative endeavors boil down to two
avenues of study. Whether you're crafting
a new dish in the kitchen or designing a
new engine, it all comes down to properties
of materials and management of energy.
The energy considerations for the Revmaster dual
alternator windings includes questions like
are the two outputs in phase with each other?
Are they the same magnitude? If so, the
system integrator might consider simply paralleling
the two windings and feeding them into a VERY robust
rectifier-regulator . . . I think there are some
small tractor products that are rated in the
30-35A class . . . a pair of 18A stators would
challenge such a device . . . if they even
exist.
A low-risk approach would be to treat the two
as separate alternators each fitted with its
own r-r. Okay, now you have to decide if
the two outputs will be simply paralled to the
same bus . . . or perhaps configured as a 'mini-
Z14" system. One of the two might drive the
main battery . . . the second could be paired
with a similar or smaller battery.
A energy study on installed dual alternators
would explore whether they are sufficiently
matched to simply parallel to a single battery/
bus. This is probably the most attractive
option for a small airplane. You would want
to load the system well into the upper regions
of capability and check to see that both
systems do a reasonable job of sharing loads.
Revmaster probably has test stands where
they can run a fully appointed engine. THEY
of all individuals are BEST situated to ponder
these and other questions. The answers would
illuminate the path to one or more practical
ways their product can be integrated into OBAM
aircraft . . .
I'll rattle their cage a bit and see if they
have already done any studies . . . or are
prepared to do them. Once that engine is bolted
to an TC airplane, the $time$ to develop the
optimal system goes up by a factor of four
to twenty times. In OBAM aviation, it's worse.
TC aircraft fixes can be propagated through
the fleet with some order of dispatch . . .
The OBAM community might re-invent the same
or similar wheels over and over again. A
needless and perhaps even hazardous waste
of time, talent and resources.
This is not a new thing nor is it unique to
OBAM aviation. Companies I've worked for have
suffered $millions$ in expense and untold damage to
customer loyalty doing development work on
fielded aircraft . . . it never turns out well.
Note to Revmaster . . . NOW is the time guys . . .
YOU need to be doing this . . .
Bob . . .
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| Subject: | Re: Schematic for twin PM alternators |
I don't understand the comment about the two generators being in or out of
phase. If they are both run through a rectifier.regulator wouldn't that
eliminate the phase concern.
I looked at a schematic for a Lockwood AirCam. This has two Rotax engines
each with magneto, rectifier/regulator, and capacitor all tied into one
battery.
Paul
On Fri, Jan 15, 2016 at 8:22 PM, user9253 <fransew@gmail.com> wrote:
>
>
> > What is the downside of both alternators connected to the battery at the
> same time.
>
> If the outputs from both alternators are exactly in phase with each other,
> then I suppose that they could be connected in parallel to a
> rectifier/regulator. The alternators may very well be in phase (if the
> wires are not connected backwards) because they are excited by the same
> rotating magnets. I do not understand how the alternators are connected to
> the rectifier/regulator in the picture that you posted. AC voltage can not
> be connected directly to a battery. The AC needs to be rectified and
> regulated first. The alternator coils can be damaged if not wired
> correctly. The trial and error method should not be used.
>
> > What is the purpose of the capacitor.
>
> The output voltage from a rectifier/regulator is pulsing DC. A capacitor
> tries to smooth out the pulses. A flywheel on an engine is analogous to a
> capacitor in a circuit. They each smooth out pulses.
>
> > If the crowbar disconnects a generator from the battery what happens.
> Is there any harm to the generator.
>
> I do not think so, but will leave that for others to answer.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=452010#452010
>
>
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| Subject: | Re: Schematic for twin PM alternators |
You are right Paul. If each generator has its own rectifier, there is no concern
about phase. But the picture that you posted appears to show an alternating
current (AC) wire connected to the battery. Without more information, I would
NOT go by that picture. Nor would I connect an AC wire from each alternator
winding to the battery.
Can you provide a link to the schematic for the Lockwood AirCam? Wiring your
alternator according to that schematic might be the way to go. A schematic is
better than a confusing picture.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452035#452035
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| Subject: | Re: Schematic for twin PM alternators |
Joe. I think you may be taking the picture too literally. I would think
the connector is hiding cross circuitry. But then this is the first
rectifier/regulator representation I've seen that relies on two wire
connection. As I read more about PM alternators and the required
rectifier/regulator when used in aircraft it seems the weak link is the
regulator. So what happens when the regulator goes bad. Do you get a high
voltage spike into the battery and avionics. If you add a crowbar to
counter this. Do you cut the feed after the regulator or possibly the AC
feed before the regulator.
The AirCam schematic is not on line. But it seems very basic to me
utilizing a rectifier/regulator plus capacitor for each engine and both
into a single battery with a single master switch and solenoid.
Paul
On Sat, Jan 16, 2016 at 2:36 PM, user9253 <fransew@gmail.com> wrote:
>
> You are right Paul. If each generator has its own rectifier, there is no
> concern about phase. But the picture that you posted appears to show an
> alternating current (AC) wire connected to the battery. Without more
> information, I would NOT go by that picture. Nor would I connect an AC
> wire from each alternator winding to the battery.
> Can you provide a link to the schematic for the Lockwood AirCam? Wiring
> your alternator according to that schematic might be the way to go. A
> schematic is better than a confusing picture.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=452035#452035
>
>
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| Subject: | Re: Schematic for twin PM alternators |
Exactly. The only issue is if the total load significantly exceeds the
rating of one side, in which case you need to know whether they can
'share' the load, as Bob mentioned.
On 1/16/2016 12:52 PM, Paul Eckenroth wrote:
> I don't understand the comment about the two generators being in or
> out of phase. If they are both run through a rectifier.regulator
> wouldn't that eliminate the phase concern.
> I looked at a schematic for a Lockwood AirCam. This has two Rotax
> engines each with magneto, rectifier/regulator, and capacitor all tied
> into one battery.
>
> Paul
>
> On Fri, Jan 15, 2016 at 8:22 PM, user9253 <fransew@gmail.com
> <mailto:fransew@gmail.com>> wrote:
>
> <fransew@gmail.com <mailto:fransew@gmail.com>>
>
>
> > What is the downside of both alternators connected to the
> battery at the same time.
>
> If the outputs from both alternators are exactly in phase with
> each other, then I suppose that they could be connected in
> parallel to a rectifier/regulator. The alternators may very well
> be in phase (if the wires are not connected backwards) because
> they are excited by the same rotating magnets. I do not
> understand how the alternators are connected to the
> rectifier/regulator in the picture that you posted. AC voltage
> can not be connected directly to a battery. The AC needs to be
> rectified and regulated first. The alternator coils can be
> damaged if not wired correctly. The trial and error method should
> not be used.
>
> > What is the purpose of the capacitor.
>
> The output voltage from a rectifier/regulator is pulsing DC. A
> capacitor tries to smooth out the pulses. A flywheel on an engine
> is analogous to a capacitor in a circuit. They each smooth out
> pulses.
>
> > If the crowbar disconnects a generator from the battery what
> happens. Is there any harm to the generator.
>
> I do not think so, but will leave that for others to answer.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=452010#452010
>
>
> ==========
> br> fts!)
> r> > w.buildersbooks.com" rel="noreferrer"
> target="_blank">www.buildersbooks.com
> rel="noreferrer" target="_blank">http://www.matronics.com/contribution
> -Matt Dralle, List Admin.
> ==========
> -
> Electric-List" rel="noreferrer"
> target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
> ==========
> FORUMS -
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> ==========
> b Site -
> -Matt Dralle, List Admin.
> rel="noreferrer" target="_blank">http://www.matronics.com/contribution
> ==========
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>
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| Subject: | AEC 12A z diagrams cropped?? |
Bob,
A non-list-member over at another forum just asked about the diagrams in
rev12A being 'cropped'. I just downloaded it, and it does appear to be
true. Ex: z-10.8 first page to 2nd page appears ok, but 2nd page right
edge cuts off all the symbols.
Can you take a look to see if there's a problem with the drawings?
Thanks,
Charlie
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| Subject: | Re: Schematic for twin PM alternators |
I agree; the drawing looks like a simple half-wave rectifier combined
with the regulator. Not the most efficient concept, but tying one end of
the coil to ground would be normal in that case.
OV protection on PM alternators is usually with a relay in series with
the output that *opens* to protect the avionics; a true 'crowbar' across
the output would take a really big shorting device and tripping a really
big circuit breaker. (There's no 'field' winding available to open.)
On 1/16/2016 2:46 PM, Paul Eckenroth wrote:
> Joe. I think you may be taking the picture too literally. I would
> think the connector is hiding cross circuitry. But then this is the
> first rectifier/regulator representation I've seen that relies on two
> wire connection. As I read more about PM alternators and the required
> rectifier/regulator when used in aircraft it seems the weak link is
> the regulator. So what happens when the regulator goes bad. Do you
> get a high voltage spike into the battery and avionics. If you add a
> crowbar to counter this. Do you cut the feed after the regulator or
> possibly the AC feed before the regulator.
> The AirCam schematic is not on line. But it seems very basic to me
> utilizing a rectifier/regulator plus capacitor for each engine and
> both into a single battery with a single master switch and solenoid.
>
> Paul
>
> On Sat, Jan 16, 2016 at 2:36 PM, user9253 <fransew@gmail.com
> <mailto:fransew@gmail.com>> wrote:
>
> <fransew@gmail.com <mailto:fransew@gmail.com>>
>
> You are right Paul. If each generator has its own rectifier,
> there is no concern about phase. But the picture that you posted
> appears to show an alternating current (AC) wire connected to the
> battery. Without more information, I would NOT go by that
> picture. Nor would I connect an AC wire from each alternator
> winding to the battery.
> Can you provide a link to the schematic for the Lockwood
> AirCam? Wiring your alternator according to that schematic might
> be the way to go. A schematic is better than a confusing picture.
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=452035#452035
>
>
> ==========
> br> fts!)
> r> > w.buildersbooks.com" rel="noreferrer"
> target="_blank">www.buildersbooks.com
> rel="noreferrer" target="_blank">http://www.matronics.com/contribution
> -Matt Dralle, List Admin.
> ==========
> -
> Electric-List" rel="noreferrer"
> target="_blank">http://www.matronics.com/Navigator?AeroElectric-List
> ==========
> FORUMS -
> eferrer" target="_blank">http://forums.matronics.com
> ==========
> b Site -
> -Matt Dralle, List Admin.
> rel="noreferrer" target="_blank">http://www.matronics.com/contribution
> ==========
>
>
Message 9
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| Subject: | Re: Schematic for twin PM alternators |
> Joe. I think you may be taking the picture too literally.
You may be right.
And you are right about the regulator being the weak link.
Many of them made for the Rotax have failed. The alternator is
unlikely to fail because it has no moving parts except for the
permanent magnets that are attached to the flywheel. The
magnets will not stop spinning unless the engine stops first,
then you have bigger problems. Usually when the regulator
fails, the voltage drops. But it would be prudent to be
prepared for other failure modes like shorts to ground or
over-voltage. That is why my schematic in a previous post has
the relays interrupting power to the regulator DC output, to isolate
a regulator that is shorted to ground from the other regulator.
If the Revmaster had only one alternator, then switching the AC
would be a more elegant way to cut charging power.
Unless your Onex will be flown IFR, using only one alternator at
a time should supply enough power.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452045#452045
Message 10
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| Subject: | Re: Schematic for twin PM alternators |
Hi All;
Please allow a 75 year old from New England, the home of sarcastic humor, to note:
So many e-mails entitled; "Schematic for Twin PM Alternators." So few schematics
actually presented.
I have two identical 12 V, 20 amp permanent magnet, internally regulated alternators
for which I have not yet developed a schematic.
That's why I'm interested.
Cheers! Stu.
----- Original Message -----
From: "user9253" <fransew@gmail.com>
Sent: Saturday, January 16, 2016 2:54:43 PM
Subject: AeroElectric-List: Re: Schematic for twin PM alternators
> Joe. I think you may be taking the picture too literally.
You may be right.
And you are right about the regulator being the weak link.
Many of them made for the Rotax have failed. The alternator is
unlikely to fail because it has no moving parts except for the
permanent magnets that are attached to the flywheel. The
magnets will not stop spinning unless the engine stops first,
then you have bigger problems. Usually when the regulator
fails, the voltage drops. But it would be prudent to be
prepared for other failure modes like shorts to ground or
over-voltage. That is why my schematic in a previous post has
the relays interrupting power to the regulator DC output, to isolate
a regulator that is shorted to ground from the other regulator.
If the Revmaster had only one alternator, then switching the AC
would be a more elegant way to cut charging power.
Unless your Onex will be flown IFR, using only one alternator at
a time should supply enough power.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452045#452045
Message 11
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| Subject: | Re: Schematic for twin PM alternators |
On January 16, 2016 10:05:28 PM CST, ashleysc@broadstripe.net wrote:
>
>Hi All;
>Please allow a 75 year old from New England, the home of sarcastic
>humor, to note:
>So many e-mails entitled; "Schematic for Twin PM Alternators." So few
>schematics actually presented.
>I have two identical 12 V, 20 amp permanent magnet, internally
>regulated alternators for which I have not yet developed a schematic.
>That's why I'm interested.
>Cheers! Stu.
>
>----- Original Message -----
>From: "user9253" <fransew@gmail.com>
>To: aeroelectric-list@matronics.com
>Sent: Saturday, January 16, 2016 2:54:43 PM
>Subject: AeroElectric-List: Re: Schematic for twin PM alternators
>
>
>
>> Joe. I think you may be taking the picture too literally.
>
>You may be right.
>And you are right about the regulator being the weak link.
>Many of them made for the Rotax have failed. The alternator is
>unlikely to fail because it has no moving parts except for the
>permanent magnets that are attached to the flywheel. The
>magnets will not stop spinning unless the engine stops first,
>then you have bigger problems. Usually when the regulator
>fails, the voltage drops. But it would be prudent to be
>prepared for other failure modes like shorts to ground or
>over-voltage. That is why my schematic in a previous post has
>the relays interrupting power to the regulator DC output, to isolate
>a regulator that is shorted to ground from the other regulator.
>If the Revmaster had only one alternator, then switching the AC
>would be a more elegant way to cut charging power.
>Unless your Onex will be flown IFR, using only one alternator at
>a time should supply enough power.
>
>--------
>Joe Gores
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=452045#452045
>
>
Hi Stu,
What brand/model are they? I've never seen a PM alt with an internal regulator.
I'd be interested in one as a backup.
Thanks,
Charlie
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
Message 12
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| Subject: | Re: Schematic for twin PM alternators |
Hi Stu! What kind of engine and alternators do you have.
It will be interesting to see the schematic that you develop.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=452050#452050
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