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Eric M. Jones
Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts
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 Posted: Wed May 21, 2008 6:42 am Post subject: Coil Suppression Techniques. |
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I have this weird Deja Vu feeling that we have covered this subject before. And I will save you the trouble Bob....I know you'll never agree, and you'll retort with a long quasi-techno piece and then stumble TO EXACTLY THE WRONG CONCLUSION.
Coil suppression and relay contact arcing have been well studied: See:
http://relays.tycoelectronics.com/appnotes/
Basically (ESPECIALLY with contactors) Do not use diodes for coil suppression unless you're hoping for greatly reduced relay/contactor life, so you can get stuck in a remote area and have an adventure. I know people like this but they usually don't build airplanes. Gotta'-Have-Drama-Dammit!
Here's what sane people have figured out:
Mechanical relays and contactors depend upon magnetism generated by an electric current running through a wire coil. When the current stops, the magnetic field collapses. But the relay does not know the difference between a wire coil moving in a magnetic field (as in a generator) or a magnetic field moving in a wire coil (as in a collapsing magnetic field). Thus a large voltage—1000V to 1500V typically—is induced in the coil. This current goes the same direction the original current did—so it slows the contact opening—allowing arcing, chatter, bouncing, contact welding and even re-closure! Yikes!
The common palliative is a diode AND zener in series, or better yet, a bidirectional zener across the coil. They call these Transils™, Surmetics™, Transorbs™, TranZorbs™, TransGuards™, Mosorbs™; the list is endless. (Over-paid executives dream up these names.) They are generic P6KE18CA bidirectional zeners.
Jeeeeeze........
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| Description: |
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Download |
| Filename: |
SnapJack.pdf |
| Filesize: |
64.84 KB |
| Downloaded: |
397 Time(s) |
| Description: |
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Download |
| Filename: |
SnapJack.pdf |
| Filesize: |
64.84 KB |
| Downloaded: |
467 Time(s) |
_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net |
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sam.marlow
Joined: 25 Feb 2006
Posts: 99
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| Posted: Wed May 21, 2008 11:50 am Post subject: Coil Suppression Techniques. |
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So Eric, do I just order a P6KE18CA, from Radio Shack, or do I need a specific Voltage rating for my relays on my 12v homebuilt?
Sam
---- "Eric M. Jones" <emjones(at)charter.net> wrote:
=============
I have this weird Deja Vu feeling that we have covered this subject before. And I will save you the trouble Bob....I know you'll never agree, and you'll retort with a long quasi-techno piece and then stumble TO EXACTLY THE WRONG CONCLUSION.
Coil suppression and relay contact arcing have been well studied: See:
http://relays.tycoelectronics.com/appnotes/
Basically (ESPECIALLY with contactors) Do not use diodes for coil suppression unless you're hoping for greatly reduced relay/contactor life, so you can get stuck in a remote area and have an adventure. I know people like this but they usually don't build airplanes. Gotta'-Have-Drama-Dammit!
Here's what sane people have figured out:
Mechanical relays and contactors depend upon magnetism generated by an electric current running through a wire coil. When the current stops, the magnetic field collapses. But the relay does not know the difference between a wire coil moving in a magnetic field (as in a generator) or a magnetic field moving in a wire coil (as in a collapsing magnetic field). Thus a large voltageâ1000V to 1500V typicallyâis induced in the coil. This current goes the same direction the original current didâso it slows the contact openingâallowing arcing, chatter, bouncing, contact welding and even re-closure! Yikes!
The common palliative is a diode AND zener in series, or better yet, a bidirectional zener across the coil. They call these Transilsâ¢, Surmeticsâ¢, Transorbsâ¢, TranZorbsâ¢, TransGuardsâ¢, Mosorbsâ¢; the list is endless. (Over-paid executives dream up these names.) They are generic P6KE18CA bidirectional zeners.
Jeeeeeze........
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=184184#184184
Attachments:
http://forums.matronics.com//files/snapjack_101.pdf
http://forums.matronics.com//files/snapjack_182.pdf
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longg(at)pjm.com
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| Posted: Wed May 21, 2008 1:37 pm Post subject: Coil Suppression Techniques. |
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So are we saying that people who market and sell relays bragging about 240,000 life clicks are full of mumbo jumbo? I know Radio Shack is. Should we buy a 40A relay to run a 30 A load and prolong the life of the switch? Jeeze, they're only a $1 more.
Are we worried about something that will only be used for the life of the airplane? Ok, in reality I only turn the headlight on say, 100 times / year. That's probably 30 times more than average. At that rate I'll be long dead before I achieve 240k clicks.
Radio Shack sells a lot of diodes to people who assume they provide feedback suppression.
My BMW has an awful lot of Bosch relays that have never worn out. What are they doing to ensure long life? I crank up the headlights, horn etc in my car 10 X more than anything I do in the airplane.
At $6 a piece I can carry a few into the backwoods.
--
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nuckolls.bob(at)cox.net
Guest
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| Posted: Wed May 21, 2008 2:51 pm Post subject: Coil Suppression Techniques. |
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|
At 07:42 AM 5/21/2008 -0700, you wrote:
| Quote: |
I have this weird Deja Vu feeling that we have covered this subject
before. And I will save you the trouble Bob....I know you'll never agree,
and you'll retort with a long quasi-techno piece and then stumble TO
EXACTLY THE WRONG CONCLUSION.
Coil suppression and relay contact arcing have been well studied: See:
|
| Quote: | http://relays.tycoelectronics.com/appnotes/
Basically (ESPECIALLY with contactors) Do not use diodes for coil
suppression unless you're hoping for greatly reduced relay/contactor life,
so you can get stuck in a remote area and have an adventure. I know people
like this but they usually don't build airplanes. Gotta'-Have-Drama-Dammit!
|
You've cited that document before. And I've
read it several times both before you cited it
and after you cited it.
Kindly point out to me where the authors offer DATA
supporting an assertion that the plain vanilla
diode coil suppression has a profound effect on relay life.
They correctly asserted and I confirmed that
diodes do indeed extend the time from switch
opening until energized contacts begin to move.
This is opening delay. They went on to extrapolate
that opening delay translates directly into slower
contact spreading velocity and extrapolated further
that this translated to increased contact wear.
I did the experiments and published the results
that argue against their extrapolations. If you
have some data to the contrary, please share it
with us.
Just because you've read some words under the
letter head and over the signatures of persons
in high places does not make their words golden
unless they're supported by data from and
understanding of repeatable experiments.
| Quote: | Here's what sane people have figured out:
|
. . . are you suggesting I am less than sane??
| Quote: | Mechanical relays and contactors depend upon magnetism generated by an
electric current running through a wire coil. When the current stops, the
magnetic field collapses. But the relay does not know the difference
between a wire coil moving in a magnetic field (as in a generator) or a
magnetic field moving in a wire coil (as in a collapsing magnetic field).
Thus a large voltage—1000V to 1500V typically—is induced in the coil.
This current goes the same direction the original current did—so it
slows the contact opening—allowing arcing, chatter, bouncing, contact
welding and even re-closure! Yikes!
|
Go to your workbench, measure it, document
it and share it with us. Show me where my
data and interpretation of my data is wrong.
The important feature of relay and contactor
operation that you're overlooking is the extreme
relationship between magnetic force and air-gap.
Air is an exceedingly poor conductor of magnetic
lines of force. So while a diode does indeed slow
the rate of drop in coil current (hence increased
delay) once the armature comes unstuck from its
seated condition, the effect of increasing
air-gap is many times more influential than rate
of decay in coil current.
Went back to the workbench to look at the S704-1 in
more detail. Here's the test setup:
http://aeroelectric.com/Pictures/Schematics/Relay_Test_Setup.pdf
Relay response with no coil suppression looks
like this:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Drop-Out_Delay_without_Diode.jpg
where we see the high voltage spike on the coil
trace and a 2.5 mS dropout delay.
WITH a coil suppression diode, we get
relay response like this:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Drop-Out_Delay_with_Diode.jpg
Dropout Delay is increased to 12.5 mS or about 5x
longer than with the diode. This was the feature
pointed out in the article you cited . . . where
the authors extrapolated this into a commensurate
slowing in contact spreading velocity (longer fires).
However, when we take the diode off and look at
transition time . . .
http://www.aeroelectric.com/Pictures/Curves/S704-1_D-E_Transition_NoSuppression.jpg
From the time the contacts FIRST open until they
first contact the opposite side is 0.6 mS. Let's
put the diode back on and we get . . .
http://www.aeroelectric.com/Pictures/Curves/S704-1_D-E_Transition_Diode_Suppression.jpg
Hmmm . . . transition increases to 0.75 mS, about
a 25% increase NOT A 500% INCREASE.
Let's go back an look at the traces I took where
we were observing the arc in a spreading set of
contacts with no diode . . .
http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeNoDiode.gif
Here I could see about 0.21 mS of "fire" as compared
with . . .
http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeNoDiode.gif
about 0.23 mS arcing when the diode was in place. Hmmm,
there was an increase but not a very big one. In both
cases, observed arcing times were about 1/3 the total
transition time.
Now let us consider another feature of relays and contactors
that REALLY drives service life issues. Take a look at:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Contact_Bounce_with_Diode.jpg
Where we see that after the first time the contacts
touch, really get with the high-tempo hat-dance
for perhaps several dozen closure and re-opening
events. This means that for every operation of the
switch on the panel, the contacts are getting
5-25 times more activity than the single switching
event might suggest. Now look at:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Contact_Bounce_without_Diode.jpg
Well fooey . . . even with the diode off the contacts
do the cat-on-a-hot-tin-roof routine.
Let us further consider that when folks like those Tyco
engineers evaluate service life, they're working in
the laboratory test environment and evaluating products
where service life is measured in the tens of thousands
of operations . . . 50,000 typical. 250,000 is not
unusual. Let us suppose that their paper was based on
real statistical studies of dozens of relays with
various coil suppression techniques and yes, there
was an observable increase in mean operations between
failures from 45,744 to 49,666 by "optimizing" the
coil suppression. Hmmm . . . 10% . . . that IS significant
to Tyco and probabably most of their customers.
They didn't speak to this kind of study in the paper
you cited and I'd like to believe they've done their
homework.
Let us assume their undocumented assertions
WERE correct on the scale I suggested. How does this
affect the OBAM aircraft builder who's switches,
relays and contactors probably won't see 5,000
operations over the lifetime of the airplane?
Further, environmental stresses will be root cause
for most replacements of such devices in personally owned,
non-revenue generating light aircraft, not electrical
stresses. In any case, the 5x increase in drop-out delay
DOES NOT extrapolate into a proportionate drop in contact
life.
| Quote: | The common palliative is a diode AND zener in series, or better yet, a
bidirectional zener across the coil. They call these Transils™,
Surmetics™, Transorbs™, TranZorbs™, TransGuards™, Mosorbs™; the
list is endless. (Over-paid executives dream up these names.) They are
generic P6KE18CA bidirectional zeners.
Jeeeeeze........
|
Eric,
Of all the contributors to this list I expect
more of you. We had some substantive discussions
on the inner technical workings of various products
and ideas in Plymouth a couple of years ago. You
struck me as one who appreciates understanding
and having a handle on the simple-ideas that go
into your recipes for success.
Please don't wave anyone's documents in the air as
justification for an extrapolation of my infirmities.
Let's not make this about you or me. May I suggest
we explore, understand and then explain the
physics. Make my day. Show me were I'm wrong.
Bob . . .
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Eric M. Jones
Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts
|
| Posted: Wed May 21, 2008 4:02 pm Post subject: Re: Coil Suppression Techniques. |
|
|
Sam,
P6KE18CA is 0.6kW 18V contained in the part number. Digikey has them. I
wouldn't ever buy airplane parts from Radio Shack. They use fallouts, defects, out of tolerance, rejects, mismarked, etc. The last parts I got from them went right into the trash can. This is another issue Bob and I always disagree on.
Or you can buy mine...."SnapJacks". I include free shipping, a handful of
Fastons, insulating tubing, etc. But whatever you do, just don't use diodes
(especially on CONTACTORS). If you REALLY don't want to use bidirectional zeners, then use the several other recommended methods better than the diode.
Eric
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net |
|
| Back to top |
|
|
sam.marlow
Joined: 25 Feb 2006
Posts: 99
|
| Posted: Wed May 21, 2008 9:30 pm Post subject: Coil Suppression Techniques. |
|
|
Should I just use a diode in series with the snapjack, is it that simple? What about sizing the components?
Thanks,
Sam
---- "Eric M. Jones" <emjones(at)charter.net> wrote:
=============
Sam,
P6KE18CA is 0.6kW 18V contained in the part number. Digikey has them. I
wouldn't ever buy airplane parts from Radio Shack. They use fallouts, defects, out of tolerance, rejects, mismarked, etc. The last parts I got from them went right into the trash can. This is another issue Bob and I always disagree on.
Or you can buy mine...."SnapJacks". I include free shipping, a handful of
Fastons, insulating tubing, etc. But whatever you do, just don't use diodes
(especially on CONTACTORS). If you REALLY don't want to use bidirectional zeners, then use the several other recommended methods better than the diode.
Eric
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=184277#184277
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umgibso1(at)yahoo.com
Guest
|
| Posted: Thu May 22, 2008 3:22 pm Post subject: Coil Suppression Techniques. |
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|
Hi Bob, on behalf of myself and many others I'm sure I'd like to thank you for - first of all, your restraint, and of course your informative posts that make it so easy for the rest of us to click on the links of your experiments.
I joined this list probably two years ago and a great deal of what was discussed was over my head (and still is!) ... I received the daily emails and for the longest time would check out the subject titles and more often than not delete the email. Over time I've 'gotten up to speed', read your book, and spent the time to learn (whether the particular subject concerned my airplane or not).
It's all too easy to "gold plate the spec" to cover ALL conceivable conditions that a particular component may see whether applicable or not. It is of GREAT value to me that you repeatedly base your responses on OBAM aircraft. Meaning... if age/environmental factors, etc is going to kill my component before I or my designed system does then thats exactly what I need to know. I have always found your posts and advice to be practical in the real world (where most of us live with our little homebuilt airplanes) and considerate of my time & money.
I continue to learn from all the contributors and contributions to the site. Best Regards to all and my apologies for feeling the need to 'waste' bandwidth! 
Tony Gibson
Winnipeg, Manitoba
Time: 03:51:31 PM PST US
From: "Robert L. Nuckolls, III" <nuckolls.bob(at)cox.net (nuckolls.bob(at)cox.net)>
Subject: Re: Coil Suppression Techniques.
At 07:42 AM 5/21/2008 -0700, you wrote:
| Quote: |
I have this weird Deja Vu feeling that we have covered this subject
before. And I will save you the trouble Bob....I know you'll never agree,
and you'll retort with a long quasi-techno piece and then stumble TO
EXACTLY THE WRONG CONCLUSION.
Coil suppression and relay contact arcing have been well studied: See:
|
| Quote: | http://relays.tycoelectronics.com/appnotes/
Basically (ESPECIALLY with contactors) Do not use diodes for coil
suppression unless you're hoping for greatly reduced relay/contactor life,
so you can get stuck in a remote area and have an adventure. I know people
like this but they usually don't build airplanes. Gotta'-Have-Drama-Dammit!
|
You've cited that document before. And I've
read it several times both before you cited it
and after you cited it.
Kindly point out to me where the authors offer DATA
supporting an assertion that the plain vanilla
diode coil suppression has a profound effect on relay life.
They correctly asserted and I confirmed that
diodes do indeed extend the time from switch
opening until energized contacts begin to move.
This is opening delay. They went on to extrapolate
that opening delay translates directly into slower
contact spreading velocity and extrapolated further
that this translated to increased contact wear.
I did the experiments and published the results
that argue against their extrapolations. If you
have some data to the contrary, please share it
with us.
Just because you've read some words under the
letter head and over the signatures of persons
in high places does not make their words golden
unless they're supported by data from and
understanding of repeatable experiments.
| Quote: | Here's what sane people have figured out:
|
. . . are you suggesting I am less than sane??
| Quote: | Mechanical relays and contactors depend upon magnetism generated by an
electric current running through a wire coil. When the current stops, the
magnetic field collapses. But the relay does not know the difference
between a wire coil moving in a magnetic field (as in a generator) or a
magnetic field moving in a wire coil (as in a collapsing magnetic field).
Thus a large voltage1000V to 1500V typicallyis induced in the coil.
This current goes the same direction the original current didso it
slows the contact openingallowing arcing, chatter, bouncing, contact
welding and even re-closure! Yikes!
|
Go to your workbench, measure it, document
it and share it with us. Show me where my
data and interpretation of my data is wrong.
The important feature of relay and contactor
operation that you're overlooking is the extreme
relationship between magnetic force and air-gap.
Air is an exceedingly poor conductor of magnetic
lines of force. So while a diode does indeed slow
the rate of drop in coil current (hence increased
delay) once the armature comes unstuck from its
seated condition, the effect of increasing
air-gap is many times more influential than rate
of decay in coil current.
Went back to the workbench to look at the S704-1 in
more detail. Here's the test setup:
http://aeroelectric.com/Pictures/Schematics/Relay_Test_Setup.pdf
Relay response with no coil suppression looks
like this:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Drop-Out_Delay_without_Diode.jpg
where we see the high voltage spike on the coil
trace and a 2.5 mS dropout delay.
WITH a coil suppression diode, we get
relay response like this:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Drop-Out_Delay_with_Diode.jpg
Dropout Delay is increased to 12.5 mS or about 5x
longer than with the diode. This was the feature
pointed out in the article you cited . . . where
the authors extrapolated this into a commensurate
slowing in contact spreading velocity (longer fires).
However, when we take the diode off and look at
transition time . . .
http://www.aeroelectric.com/Pictures/Curves/S704-1_D-E_Transition_NoSuppression.jpg
From the time the contacts FIRST open until they
first contact the opposite side is 0.6 mS. Let's
put the diode back on and we get . . .
http://www.aeroelectric.com/Pictures/Curves/S704-1_D-E_Transition_Diode_Suppression.jpg
Hmmm . . . transition increases to 0.75 mS, about
a 25% increase NOT A 500% INCREASE.
Let's go back an look at the traces I took where
we were observing the arc in a spreading set of
contacts with no diode . . .
http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeNoDiode.gif
Here I could see about 0.21 mS of "fire" as compared
with . . .
http://www.aeroelectric.com/Pictures/Curves/704-1OpeningTimeNoDiode.gif
about 0.23 mS arcing when the diode was in place. Hmmm,
there was an increase but not a very big one. In both
cases, observed arcing times were about 1/3 the total
transition time.
Now let us consider another feature of relays and contactors
that REALLY drives service life issues. Take a look at:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Contact_Bounce_with_Diode.jpg
Where we see that after the first time the contacts
touch, really get with the high-tempo hat-dance
for perhaps several dozen closure and re-opening
events. This means that for every operation of the
switch on the panel, the contacts are getting
5-25 times more activity than the single switching
event might suggest. Now look at:
http://www.aeroelectric.com/Pictures/Curves/S704-1_Contact_Bounce_without_Diode.jpg
Well fooey . . . even with the diode off the contacts
do the cat-on-a-hot-tin-roof routine.
Let us further consider that when folks like those Tyco
engineers evaluate service life, they're working in
the laboratory test environment and evaluating products
where service life is measured in the tens of thousands
of operations . . . 50,000 typical. 250,000 is not
unusual. Let us suppose that their paper was based on
real statistical studies of dozens of relays with
various coil suppression techniques and yes, there
was an observable increase in mean operations between
failures from 45,744 to 49,666 by "optimizing" the
coil suppression. Hmmm . . . 10% . . . that IS significant
to Tyco and probabably most of their customers.
They didn't speak to this kind of study in the paper
you cited and I'd like to believe they've done their
homework.
Let us assume their undocumented assertions
WERE correct on the scale I suggested. How does this
affect the OBAM aircraft builder who's switches,
relays and contactors probably won't see 5,000
operations over the lifetime of the airplane?
Further, environmental stresses will be root cause
for most replacements of such devices in personally owned,
non-revenue generating light aircraft, not electrical
stresses. In any case, the 5x increase in drop-out delay
DOES NOT extrapolate into a proportionate drop in contact
life.
| Quote: | The common palliative is a diode AND zener in series, or better yet, a
bidirectional zener across the coil. They call these Transils,
Surmetics, Transorbs, TranZorbs, TransGuards, Mosorbs; the
list is endless. (Over-paid executives dream up these names.) They are
generic P6KE18CA bidirectional zeners.
Jeeeeeze........
|
Eric,
Of all the contributors to this list I expect
more of you. We had some substantive discussions
on the inner technical workings of various products
and ideas in Plymouth a couple of years ago. You
struck me as one who appreciates understanding
and having a handle on the simple-ideas that go
into your recipes for success.
Please don't wave anyone's documents in the air as
justification for an extrapolation of my infirmities.
Let's not make this about you or me. May I suggest
we explore, understand and then explain the
physics. Make my day. Show me were I'm wrong.
Bob . . .
[quote][b]
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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nuckolls.bob(at)cox.net
Guest
|
| Posted: Fri May 23, 2008 6:44 am Post subject: Coil Suppression Techniques. |
|
|
At 04:16 PM 5/22/2008 -0700, you wrote:
| Quote: | Hi Bob, on behalf of myself and many others I'm sure I'd like to thank you
for - first of all, your restraint, and of course your informative posts
that make it so easy for the rest of us to click on the links of your
experiments.
I joined this list probably two years ago and a great deal of what was
discussed was over my head (and still is!) ... I received the daily emails
and for the longest time would check out the subject titles and more often
than not delete the email. Over time I've 'gotten up to speed', read your
book, and spent the time to learn (whether the particular subject
concerned my airplane or not).
|
That's what Richard Feynman describes as "The
Pleasure of Finding Things Out". Virtually every
classroom we all sat in for the first time offered
tons of information sometimes accompanied with
lucid explanation and even real-life connections.
It is not uncommon when "getting a drink from the
fire hose" that certain simple-ideas don't catch
on or fit into the current library of life experiences.
But as you've alluded, there is an osmosis
effect . . . tiny bits of the big drink soak
in. At some point in the future, a sort of
epiphany may take place when one realizes that
"Yeah, I KNOW how that works".
It still happens to me regularly.
| Quote: |
It's all too easy to "gold plate the spec" to cover ALL conceivable
conditions that a particular component may see whether applicable or
not. It is of GREAT value to me that you repeatedly base your responses
on OBAM aircraft. Meaning... if age/environmental factors, etc is going
to kill my component before I or my designed system does then thats
exactly what I need to know. I have always found your posts and advice to
be practical in the real world (where most of us live with our little
homebuilt airplanes) and considerate of my time & money.
|
To me, being an engineer was the ideal connection
between pure physics and people. I was exceedingly
fortunate in my career to have some good teachers
AND a charter to make my ideas play in the marketplace.
I.e, offer competitive value that was attractive
for performance, price and after-the-sale service.
VERY few of my contemporaries have enjoyed so broad
an experience.
| Quote: |
I continue to learn from all the contributors and contributions to the
site. Best Regards to all and my apologies for feeling the need to
'waste' bandwidth!
|
Forgive me but that "wasted bandwidth" canard is
really raises the ol' blood pressure. It seems most
often used by individuals who complain to other
individuals about the use of a communications tool
that is nobody's property . . . a term almost never
used in a exchange that quests for understanding of
simple ideas.
If one wants to bemoan "wasted bandwidth", just
hit any cable channel for an hour and make notes on
what one learns that adds any value to their lives.
I.e., how did the $time$ spent today make one's life
any more enjoyable or confident tomorrow?
I view $time$ spent here as an opportunity to
fine tune my own skills as well as encouragement
to broaden my own understanding. Folks on the List
are not always aware of the $time$ spent to firm
up a foundation for an reply before I post it.
You folks are as useful to me as I hope I am to
all of you. $Time$ and 'bandwidth' used in that
endeavor is never a waste.
Everyone on the List has an opportunity to be both
student and teacher. It has nothing to do with
the total experience of either individual. Any
instance where understanding supported by repeatable
experiment is exchanged, there is opportunity
for growth for everyone who chooses to
participate.
Bob . . .
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bobf(at)feldtman.com
Guest
|
| Posted: Sat May 24, 2008 5:10 am Post subject: Coil Suppression Techniques. |
|
|
Cable TV is wasted bandwidth (except for cool channels like military channel, national geographic, NASCAR etc..) Otherwise I think cable TV kills Betz cells.. (that'll send folks heading for wikipedpia!)
bobf
On 5/23/08, Robert L. Nuckolls, III <nuckolls.bob(at)cox.net (nuckolls.bob(at)cox.net)> wrote:[quote] --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckolls.bob(at)cox.net (nuckolls.bob(at)cox.net)>
At 04:16 PM 5/22/2008 -0700, you wrote:
| Quote: | Hi Bob, on behalf of myself and many others I'm sure I'd like to thank you for - first of all, your restraint, and of course your informative posts that make it so easy for the rest of us to click on the links of your experiments.
I joined this list probably two years ago and a great deal of what was discussed was over my head (and still is!) ... I received the daily emails and for the longest time would check out the subject titles and more often than not delete the email. Over time I've 'gotten up to speed', read your book, and spent the time to learn (whether the particular subject concerned my airplane or not).
|
That's what Richard Feynman describes as "The
Pleasure of Finding Things Out". Virtually every
classroom we all sat in for the first time offered
tons of information sometimes accompanied with
lucid explanation and even real-life connections.
It is not uncommon when "getting a drink from the
fire hose" that certain simple-ideas don't catch
on or fit into the current library of life experiences.
But as you've alluded, there is an osmosis
effect . . . tiny bits of the big drink soak
in. At some point in the future, a sort of
epiphany may take place when one realizes that
"Yeah, I KNOW how that works".
It still happens to me regularly.
| Quote: |
It's all too easy to "gold plate the spec" to cover ALL conceivable conditions that a particular component may see whether applicable or not. It is of GREAT value to me that you repeatedly base your responses on OBAM aircraft. Meaning... if age/environmental factors, etc is going to kill my component before I or my designed system does then thats exactly what I need to know. I have always found your posts and advice to be practical in the real world (where most of us live with our little homebuilt airplanes) and considerate of my time & money.
|
To me, being an engineer was the ideal connection
between pure physics and people. I was exceedingly
fortunate in my career to have some good teachers
AND a charter to make my ideas play in the marketplace.
I.e, offer competitive value that was attractive
for performance, price and after-the-sale service.
VERY few of my contemporaries have enjoyed so broad
an experience.
| Quote: |
I continue to learn from all the contributors and contributions to the site. Best Regards to all and my apologies for feeling the need to 'waste' bandwidth!
|
Forgive me but that "wasted bandwidth" canard is
really raises the ol' blood pressure. It seems most
often used by individuals who complain to other
individuals about the use of a communications tool
that is nobody's property . . . a term almost never
used in a exchange that quests for understanding of
simple ideas.
If one wants to bemoan "wasted bandwidth", just
hit any cable channel for an hour and make notes on
what one learns that adds any value to their lives.
I.e., how did the $time$ spent today make one's life
any more enjoyable or confident tomorrow?
I view $time$ spent here as an opportunity to
fine tune my own skills as well as encouragement
to broaden my own understanding. Folks on the List
are not always aware of the $time$ spent to firm
up a foundation for an reply before I post it.
You folks are as useful to me as I hope I am to
all of you. $Time$ and 'bandwidth' used in that
endeavor is never a waste.
Everyone on the List has an opportunity to be both
student and teacher. It has nothing to do with
the total experience of either individual. Any
instance where understanding supported by repeatable
[b]
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harley(at)AgelessWings.co
Guest
|
| Posted: Sat May 24, 2008 5:37 am Post subject: Coil Suppression Techniques. |
|
|
Right...thanks Bob...now I have to look up a web page full of more terms and words!
Excerpt from Wikipedia:
"Betz cells have one apical dendrite typical to pyramidal neurons, they have more primary dendritic shafts, and these do not leave the soma only at basal angles but rather branch out from almost any point asymmetrically."
Harley
Robert Feldtman wrote: [quote]Cable TV is wasted bandwidth (except for cool channels like military channel, national geographic, NASCAR etc..) Otherwise I think cable TV kills Betz cells.. (that'll send folks heading for wikipedpia!)
bobf
[b]
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