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Lee Logan
Joined: 10 Jan 2006
Posts: 86
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 Posted: Sat Jan 27, 2007 7:19 pm Post subject: AeroElectric-List Digest: 21 Msgs - 01/26/07 |
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Bob: You said, "I'm not going to respond to the lack of understanding and substance in your last postings" in your response to George's comments on internally regulated alternators. But isn't he just saying pretty much what the Plane Power people, brochures, and product specs say? Tough for us "pilots" out here to know the "electrical truth" when the experts are this far apart on the "facts".
Allow me to summarize what I believe I have heard over the last several months on this forum and where I think this leaves those of us who just want to build a safe, operationally flexible airplane and FLY it: One side says that modern internally regulated alternators are reliable and fundamentally sound, and indeed, cutting edge designs. They are said to rarely fail and when they do to do so generally in an orderly fashion. The Plane Power design for one, is said even to eliminate the last vestiges of the concerns in the anti-internally regulated argument.
The "other side" says this is not true and that internally regulated alternators are fundamentally and fatally flawed with respect to their penchant for a potentially damaging and dangerous runaway voltage/amperage excursion. They are not foolproof by any means and in fact, fail often enough to give legitimate pause to anyone considering their use. A potential "fix" is said to be in the works for some as yet, unannounced future date, however.
These two positions are about as far apart as it is possible to be, it seems to me and has left me and perhaps others wondering which system to "bet" on in our own aircraft. I for one, have listened to the debate in this forum for months and am no better informed at this point than I was when I started. Technically, I suppose, that is not accurate. I know a GREAT deal more than I did before (thanks very much to all who have contributed), but with respect to the fundamental issue of which systems works best or is most suitable for a high end OBAM all electric aircraft, I STILL don't know which has been better justified through this debate. And, like many others I suspect, I don't really have a horse in this race---I just want to make the right choice for my aircraft.
If it is true that there is neither "understanding" nor "substance" to the arguments made in favor of the internally regulated Plane Power alternator (and perhaps others like them which claim orderly and infrequent failure modes), then it seems to me they should be taken off the market and prevented from endangering the aircraft they might be installed in. I'm having trouble believeing that is the case with these modern and apparently cutting edge designs, but I'm also having trouble reading your most recent comments any other way. I have no connection to any entity in this debate and none with Plane Power or any other manufacturer. I'm just trying to figure out which alternator to put on my airplane. Are internally regulated alternators now considered by forum experts to be so fundamentally flawed and inapproprite in OBAM aircraft as to be beyond discussion?
Scratching my head in South Carolina,
Lee...
[quote][b]
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aurbo(at)ak.net
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| Posted: Sat Jan 27, 2007 7:37 pm Post subject: AeroElectric-List Digest: 21 Msgs - 01/26/07 |
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Lee,
I scratched my head in Alaska and decided to use the Plane Power route. And "horrors" I will not be using any other over voltage protection! But if and when I do have a problem I will be glad to share it with others.
Done scratching and now I will continue on with building an "experimental" aircraft.
Mike Ice
Anchorage, Alaska
RV-9 electrical almost done
canopy next.
[quote] ---
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sportav8r(at)gmail.com
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| Posted: Sat Jan 27, 2007 8:21 pm Post subject: AeroElectric-List Digest: 21 Msgs - 01/26/07 |
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Lee,
It will be interesting to hear what Bob's latest thinking is on this
big question as you have phrased it (great job, BTW).
Meanwhile, here is how I have forged ahead, while awaiting the
promised protection circuit module from Bob's R&D efforts:
I am putting a 55 amp I-VR alternator in the plane with a backup SD-8
alternator (basic Z-13/8 so far...) My essentials or endurance bus is
actually an avionics bus; all my expensive glass-cockpit IFR goodies
go there. This bus has a tiny backup battery to allow the avionics to
initialize while the big Odyssey battery handles engine cranking
chores, and to keep the avionics booted up in what follows below. The
avionics bus has an alternate feed path from the always-hot battery
bus that is normally OPEN. Primary feed of power to the avionics bus
is from the main bus, where the heavy, resistive loads like lights,
seat heaters, pitot heat reside, and this feed is through a small
Bosch ice cube relay governed by a solid state OV module from
Perihelion Design.
An overvolt event of 16.2 volts immediately trips out the relay and
isolates the avionics bus from the surging alternator and the main bus
and big battery, which are left connected to the alternator (no big
load dump so far...) Manual switching in an orderly left-to-right
sequence on my switch sub-panel takes the main bus offline, then opens
the battery contactor (two-stage load dump) and brings alive the SD-8,
which is connected to the main battery and needs no bootstrap circuit
to bring the regulator alive. One more switch flick ties the avionics
bus to the battery bus, drawing power from the Odyssey and the SD-8.
Such pilot switch-throwing is anathema to some designer's goals, but
takes about two seconds and can be done without looking, the way mine
are laid out. If a reset of the OV module seems to clear the fault,
and it looks like it was a nuisance trip, reversing the switch
sequence restores everything to the way it was before the event,
provided the big alternator was not harmed.
The part I like best is that the protection of the high-dollar and
mission-critical avionics suite is automatic and instantaneous (okay,
I'm not sure of the relay action times but it's darned fast). If the
stuff on the main bus gets fried by a few seconds of rising voltage,
gee, that's too bad. Light bulbs and seat heaters can be replaced
cheaply. The battery should be able to endure a few seconds without
catastrophic failure before it, too, is isolated from the overvoltage.
Not the perfect system, but it was cheap and light and easy to design
and implement and has what I like. I've gone out of my way to
engineer the human-switch interface to make the handling of an event
straightforward in my RV. That said, I hope I never have to practice
that particular drill.
I'll forward the Excel schematic to any interested parties. The more
people who look this over before it actually flies, the happier I'll
be.
-Bill B
On 1/27/07, Lee Logan <leeloganster(at)gmail.com> wrote:
| Quote: | Bob: You said, "I'm not going to respond to the lack of understanding and
substance in your last postings" in your response to George's comments on
internally regulated alternators. But isn't he just saying pretty much what
the Plane Power people, brochures, and product specs say? Tough for us
"pilots" out here to know the "electrical truth" when the experts are this
far apart on the "facts".
Allow me to summarize what I believe I have heard over the last several
months on this forum and where I think this leaves those of us who just want
to build a safe, operationally flexible airplane and FLY it: One side says
that modern internally regulated alternators are reliable and fundamentally
sound, and indeed, cutting edge designs. They are said to rarely fail and
when they do to do so generally in an orderly fashion. The Plane Power
design for one, is said even to eliminate the last vestiges of the concerns
in the anti-internally regulated argument.
The "other side" says this is not true and that internally regulated
alternators are fundamentally and fatally flawed with respect to their
penchant for a potentially damaging and dangerous runaway voltage/amperage
excursion. They are not foolproof by any means and in fact, fail often
enough to give legitimate pause to anyone considering their use. A potential
"fix" is said to be in the works for some as yet, unannounced future date,
however.
These two positions are about as far apart as it is possible to be, it seems
to me and has left me and perhaps others wondering which system to "bet" on
in our own aircraft. I for one, have listened to the debate in this forum
for months and am no better informed at this point than I was when I
started. Technically, I suppose, that is not accurate. I know a GREAT deal
more than I did before (thanks very much to all who have contributed), but
with respect to the fundamental issue of which systems works best or is most
suitable for a high end OBAM all electric aircraft, I STILL don't know which
has been better justified through this debate. And, like many others I
suspect, I don't really have a horse in this race---I just want to make the
right choice for my aircraft.
If it is true that there is neither "understanding" nor "substance" to the
arguments made in favor of the internally regulated Plane Power alternator
(and perhaps others like them which claim orderly and infrequent failure
modes), then it seems to me they should be taken off the market and
prevented from endangering the aircraft they might be installed in. I'm
having trouble believeing that is the case with these modern and apparently
cutting edge designs, but I'm also having trouble reading your most recent
comments any other way. I have no connection to any entity in this debate
and none with Plane Power or any other manufacturer. I'm just trying to
figure out which alternator to put on my airplane. Are internally regulated
alternators now considered by forum experts to be so fundamentally flawed
and inapproprite in OBAM aircraft as to be beyond discussion?
Scratching my head in South Carolina,
Lee...
http://www.matronics.com/Navigator?AeroElectric-List
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echristley(at)nc.rr.com
Guest
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| Posted: Sat Jan 27, 2007 8:58 pm Post subject: AeroElectric-List Digest: 21 Msgs - 01/26/07 |
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Lee Logan wrote:
| Quote: |
The "other side" says this is not true and that internally regulated
alternators are fundamentally and fatally flawed with respect to their
penchant for a potentially damaging and dangerous runaway
voltage/amperage
excursion. They are not foolproof by any means and in fact, fail often
enough to give legitimate pause to anyone considering their use. A
potential
"fix" is said to be in the works for some as yet, unannounced future
date,
however.
That doesn't represent what I've come to understand as Bob's position.
|
He has stated repeatedly that the I-VR is reliable and at a very low
risk of damaging other systems. He has added the caveat that there IS
risk, just not much. His objection is that the pilot does not have the
control to shut it down. It's immaterial whether the control is needed
for a runaway voltage condition, or to verify the veracity of a back
electron pump of some sort. The design goal that he has embraced calls
for the pilot to have complete control over all systems, and the IVR
takes some of that away.
George, OTOH, has argued that the IVR can handle alternator control
better than the pilot. The overvoltage failures that have occured with
quality hardware were mild in nature and easily dealt with. I don't
see Bob taking an issue with that. He contends that the pilot should
have control, regardless.
I believe Bob has recognized many of the benefits of I-VR (like lower
cost, wide availability, and some neato whizzy electronic features),
and is working on a system that will alleviate the remaining issue that
he has with lack of control.
I work in a technical field, and I see this sort of debate all the
time. I have issues. You have issues. We bang heads and together
arrive at a system that's better than what either of us would have
designed alone. That's the good stuff. The rest is noise.
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mwcreek(at)frontiernet.ne
Guest
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| Posted: Sat Jan 27, 2007 8:59 pm Post subject: AeroElectric-List Digest: 21 Msgs - 01/26/07 |
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Well put Lee. Thank you for a well written and thought out post.
I’m working hard to get my plane flying by this summer and have purchased a IR ND, but I’m really wondering if that is the right choice. I haven’t wired the alt system yet so it would be easy to change, but like you I am really wondering what the best solution is at his point so I can charge ahead with the confidence that I’m building a safe bird.
Mike C.
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Lee Logan
Sent: Saturday, January 27, 2007 7:19 PM
To: aeroelectric-list(at)matronics.com
Subject: Re: AeroElectric-List Digest: 21 Msgs - 01/26/07
Bob: You said, "I'm not going to respond to the lack of understanding and substance in your last postings" in your response to George's comments on internally regulated alternators. But isn't he just saying pretty much what the Plane Power people, brochures, and product specs say? Tough for us "pilots" out here to know the "electrical truth" when the experts are this far apart on the "facts".
Allow me to summarize what I believe I have heard over the last several months on this forum and where I think this leaves those of us who just want to build a safe, operationally flexible airplane and FLY it: One side says that modern internally regulated alternators are reliable and fundamentally sound, and indeed, cutting edge designs. They are said to rarely fail and when they do to do so generally in an orderly fashion. The Plane Power design for one, is said even to eliminate the last vestiges of the concerns in the anti-internally regulated argument.
The "other side" says this is not true and that internally regulated alternators are fundamentally and fatally flawed with respect to their penchant for a potentially damaging and dangerous runaway voltage/amperage excursion. They are not foolproof by any means and in fact, fail often enough to give legitimate pause to anyone considering their use. A potential "fix" is said to be in the works for some as yet, unannounced future date, however.
These two positions are about as far apart as it is possible to be, it seems to me and has left me and perhaps others wondering which system to "bet" on in our own aircraft. I for one, have listened to the debate in this forum for months and am no better informed at this point than I was when I started. Technically, I suppose, that is not accurate. I know a GREAT deal more than I did before (thanks very much to all who have contributed), but with respect to the fundamental issue of which systems works best or is most suitable for a high end OBAM all electric aircraft, I STILL don't know which has been better justified through this debate. And, like many others I suspect, I don't really have a horse in this race---I just want to make the right choice for my aircraft.
If it is true that there is neither "understanding" nor "substance" to the arguments made in favor of the internally regulated Plane Power alternator (and perhaps others like them which claim orderly and infrequent failure modes), then it seems to me they should be taken off the market and prevented from endangering the aircraft they might be installed in. I'm having trouble believeing that is the case with these modern and apparently cutting edge designs, but I'm also having trouble reading your most recent comments any other way. I have no connection to any entity in this debate and none with Plane Power or any other manufacturer. I'm just trying to figure out which alternator to put on my airplane. Are internally regulated alternators now considered by forum experts to be so fundamentally flawed and inapproprite in OBAM aircraft as to be beyond discussion?
Scratching my head in South Carolina,
Lee...
| Quote: | | http://www.matronics.com/Navigator?AeroElectric-List |
01234
[quote][b]
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