Today's Message Index:
----------------------
1. 05:03 AM - Re: Re: Looking for suggestions (Henador Titzoff)
2. 05:20 AM - Re: Regarding Capacitor Filters (Bob Verwey)
3. 05:41 AM - Re: Open source product development for OBAM aircraft (Eric M. Jones)
4. 07:32 AM - Shuttle fly-by (Doug Ilg)
5. 08:35 AM - The wild and wooly world of environmental compatability (Robert L. Nuckolls, III)
6. 08:48 AM - Re: Shuttle fly-by (Robert L. Nuckolls, III)
7. 10:18 AM - Re: Re: Open source product development for OBAM aircraft (Robert L. Nuckolls, III)
8. 07:31 PM - Re: Re: Looking for suggestions (Robert L. Nuckolls, III)
9. 07:33 PM - Re: Open source product development for OBAM aircraft (rez)
10. 08:03 PM - Re: Re: Open source product development for OBAM aircraft (Henador Titzoff)
11. 08:04 PM - Re: Re: Open source product development for OBAM aircraft (Richard E. Tasker)
12. 10:03 PM - Re: Re: Open source product development for OBAM aircraft (Robert L. Nuckolls, III)
13. 10:04 PM - Re: Re: Looking for suggestions (Dan Billingsley)
Message 1
INDEX | Back to Main INDEX |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Looking for suggestions |
Joe,=0A=0AA larger conductor would help only if the noise you perceive is c
ausing problems is actually an offset voltage caused by current times resis
tance in the wire. -In other words, current pulled by one load can cause
an offset voltage for the second load, and the second load can't handle the
offset.=0A=0ABut noise is AC with a spectrum content up there at high freq
uencies. -So when you say "noise," let's assume it is high frequency nois
e. If this is true, increasing conductor size only helps if it decreases it
s impedance, which is unlikely. -You're better off rewiring such that eac
h load has its own dedicated ground and power wires.=0A-=0AHenador Titzof
f=0A=0A=0A=0A________________________________=0A From: user9253 <fran4sew@b
anyanol.com>=0ATo: aeroelectric-list@matronics.com =0ASent: Tuesday, April
17, 2012 12:08 AM=0ASubject: AeroElectric-List: Re: Looking for suggestions
ol.com>=0A=0ABob,=0ASince noise can be caused by two or more circuits shari
ng the same conductor, would it help to use a larger conductor?- Have any
experiments been done comparing noise with various wire sizes?=0AJoe=0A=0A
--------=0AJoe Gores=0A=0A=0A=0A=0ARead this topic online here:=0A=0Ahttp:/
/forums.matronics.com/viewtopic.php?p=371015#371015=0A=0A=0A=0A=0A=0A=0A
=========================0A
===================
Message 2
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Regarding Capacitor Filters |
Thanks Eric!
As always, fascinating and informative for us techno 'heat seekers' out there!
Bob Verwey
On 17/04/2012, Eric M. Jones <emjones@charter.net> wrote:
> <emjones@charter.net>
>
> I have watched the conversation regarding the big capacitor for filtering
> the generator/alternator/dynamo/etc. and want to make a few comments:
>
> 1) Usually a capacitor doesn't get charged to a higher voltage that was
> applied. But this is not true in all cases. Capacitors can and do "space
> charge" (all by themselves) to extremely high voltages. Really big,
> efficient, very high ESR (Equivalent Series Resistance--usually high
> voltage) caps are stored and shipped with a shorting strap for this reason.
> And yes, this doesn't have much to do with OUR situation. ...but just
> sayin'....don't learn stuff that ain't true.
>
> 2) Capacitors are almost always used with a "bleeder" resistor that
> guarantees that any retained charge will be dissipated in a short time after
> the power is removed. A capacitor is really a battery that should be
> disconnected or discharged if you are going to crash your airplane. You can
> calculate this (Google "capacitor bleed resistor calculator") but for
> general purposes a 200 ohm 2W resistor across the capacitor terminals will
> lower 15V to 5V in 5 seconds for a 22000 uF cap). Should you add one?
> Consider that the resistor improves the filtering all by itself and only add
> 75 mA to the load. So YES!
>
> 2) An electrolytic capacitor can be subjected to any number of insults. Some
> of these can easily be prevented. Lets look at a typical part: A CDE
> Capacitor about the size of a D-cell battery: SLPX223M025H5P330 X 40 mm. 25
> Vdc (32 Vdc Surge)
>
> High applied voltages damage the foil plates. These plates are self-healing
> usually, but they steadily degrade. Use a parallel Zener with a Vz below the
> withstand V of the capacitor for a longer, happier life.
>
> Temperature. Keep the cap far away from major heat sources (easy). Keep the
> cap from extreme cold (harder). Watch those environmental specs. Capacitor
> actually perform better HOT, but have shorter lifetimes. At -40C cold
> (brrrrrr) the capacitance is about 1/10 of what it is when hotbut they
> warm up fast.
>
> Common Electrolytic caps have a limited lifetimein this example 3000
> hours. So you should perhaps replace it with at engine TBO, or if permanency
> is what you want, choose a different part.
>
> For filtering, a capacitor is only part of the answer. Any decent filter
> uses a resistor (R), an inductor (L), in addition to a capacitor (C). These
> are called RLC filters, and usually have a small ceramic cap and a Zener
> too. Standard automotive filters are made like this and work fine in 14.5V
> aircraft applications.
>
> See: http://www.jmkfilters.com/autofilterssc1.htm
>
> --------
> 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=371002#371002
>
>
Message 3
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Open source product development for OBAM aircraft |
Tip:
As in most cool electro-parts, "Deal Extreme" has Arduino (and other) parts and
a vast selection of extremely cheap accessories for wanna-be-programmers. Cheap
cheap cheap. And free shipping.
--------
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=371029#371029
Message 4
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
I just got down from the roof of the building I work in.- We =0Awatched t
he Space Shuttle Discovery do its tour or DC atop its 747 =0Acarrier.- It
made 2 passes very close to our building (we are under the =0Aflight path
for National Airport) with a T-38 in trail.- I'd attach a =0Apicture, but
we aren't allowed to have cameras, here.=0A=0AVery cool.- And a bit sad.
=0AThought all you aviation groupies might be interested.=0A-=0ADoug Ilg
=0AGrumman Tiger N74818, College Park-Airport (KCGS), Maryland=0AChalleng
er II LSS LW (N641LG-reserved)-- kit underway at Laurel Suburban (W18)
Message 5
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | The wild and wooly world of environmental compatability |
At 07:02 AM 4/17/2012, you wrote:
Joe,
A larger conductor would help only if the noise you perceive is
causing problems is actually an offset voltage caused by current
times resistance in the wire. In other words, current pulled by one
load can cause an offset voltage for the second load, and the second
load can't handle the offset.
But noise is AC with a spectrum content up there at high
frequencies. So when you say "noise," let's assume it is high
frequency noise. If this is true, increasing conductor size only
helps if it decreases its impedance, which is unlikely. You're
better off rewiring such that each load has its own dedicated ground
and power wires.
Henador Titzoff
Henador brings up an excellent point. The energy
sources we like to bundle together under the heading
of "antagonists" has a spectrum of qualities that include
manifestations of current, voltage, frequency, magnetic
field, electric field and even mass and velocity.
The situations we encounter most in small airplanes
are those that cause buzzes, whines, pops and other
audible effects. Then too we see changes in performance
in response to keying an on-board transmitter or flying
past a high energy RF source.
But the spectrum of potential antagonists goes lower
than audio down to DC. I related a story in the 'Connection
where a LongEz builder complained of his engine gages
shifting when the alternator was turned on/off. This was
an instance where the instruments were 'grounded' up
front at the battery . . . the sensors were 'grounded'
at the rear on the engine. The two 'grounds' were tied
together with a 10AWG piece of wire. The several hundred
millivolt shift in potential between the two grounds
as a result of alternator current upset the instruments
that were capable of displaying differences in the
tens of millivolts.
I worked what one might call the ultimate ground
loop example for RF on an airplane that featured
a HF communications antenna as part of the leading
edge structure of the vertical fin. This was a
'product upgrade' from the legacy long-wire antenna
that used to adorn the top of the airplane. Owners
of these $10 million$ airplanes really liked it
when those wires disappeared.
Emacs!
Problem was, what used to be a high voltage, low
current excitation of a wire was morphed into
a low voltage, high current excitation of structure.
The 'antenna' part of the new design worked fine.
However, the 'ground' part of the system was designed
decades earlier to be strong, the right shape and
corrosion resistant. None of the various parts of
the airplane structure were attached to each other
in anticipation of carrying high current flows at
2 to 30 Mhz.
The unanticipated result gave us antagonistic
levels of RF in the 'hell hole' that far exceeded
the susceptibilities limits for several systems
that were also designed and qualified onto the
airplane decades earlier. Further, the problem
manifested only at specific frequencies that
shifted from airplane to airplane. The problem
I was tasked with involved generator regulators
that shut down when the transmitter was keyed
on specific frequencies.
I couldn't expect all those regulators to be replaced
with modern and more robust designs. I ended up crafting a
filter-connector . . .
Emacs!
Emacs!
. . . which was nothing more than capacitors bypassing
certain pins to ground under the connector's back shell.
We COULD have ordered a custom connector with those
capacitors already installed but this was Dec 5th and
I was working a group of airplanes that had to be
delivered before Jan 1.
I mentioned antagonists with mass and velocity.
When designing hardware for spacecraft, the well
schooled system designer calls for radiation hardening
of the purchased products. Cosmic rays flying through the
memory cell of a computer chip can change the state
of that cell thus corrupting the data it represents
. . . or even killing the cell making it useless.
Products we delivered to the Navy had to be
qualified to work aboard aircraft carriers with
megawatt pulsed radars on board. Whole different
ball game.
Henador reminds us that artful system integration
demands a careful matching of design goals for
performance against environmental conditions that
go far beyond temperature, humidity, vibration, etc.
The short answer to your question is, "Yes. Changing
the size of the antagonist conductor will have an
influence on the level of perceived interference."
I will suggest that MOST airplanes flying today probably
have some measurable level of interference effects between
many combinations of two systems . . . they're just small
enough to be insignificant from the pilot's perspective.
As I discussed in the chapter on noise, beating the
'noise' down to acceptable (if not zero) effects
requires identification of victim, antagonist and
propagation mode. Attenuating propagation may prove
to be the elegant solution. However, eliminating the
propagation mode is the best. In the case of ground
loops, careful attention to architecture will drive
the potential for propagation via that pathway to zero.
Bob . . .
Message 6
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Shuttle fly-by |
At 09:30 AM 4/17/2012, you wrote:
>I just got down from the roof of the building I work in. We watched
>the Space Shuttle Discovery do its tour or DC atop its 747
>carrier. It made 2 passes very close to our building (we are under
>the flight path for National Airport) with a T-38 in trail. I'd
>attach a picture, but we aren't allowed to have cameras, here.
>
>Very cool. And a bit sad.
It's good that these fledgling examples of 'space
travel' be preserved and remembered for the benefits
realized and the risks endured to get this far. The
REALLY sad fact is that the folks who designed,
crafted, maintained and flew these machines do not
have the next generation trailing in their footsteps.
But maybe things are going along as they should
be. There was a short time in aviation history that
airplanes like this were the epitome of successful
design goals . . .
http://tinyurl.com/7jn9rgl
The machines that replaced them were so much faster
that one didn't need to Plan on sleeping through
part of the trip . . . or exploiting the work-product
of an on-board chef! The succeeding generations now
carry us through lethal atmospheres at speeds many
times faster than driving at a fraction of the cost
of driving.
The future is yet to come . . .
Bob . . .
Message 7
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Open source product development for OBAM |
aircraft
The ECB layout is done. I'll put it down for a few
hours and then 'proof' it against the schematic.
I'll publish the ECB layout and schematic as soon
as I've confirmed their agreement.
Bob . . .
Message 8
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Looking for suggestions |
At 09:24 PM 4/16/2012, you wrote:
We need to do some experiments to see where the noise
is getting into the system.
When you CAN hear the noise, is it affected by the
volume control on the radio?
Does your transmitter have a side-tone feature,
in other words, can you hear yourself in the
headphones when you talk on the transmitter?
Does the noise go away when you transmit?
If I recall correctly, the noise does go away
when you close the alternate feed switch to
the e-bus.
Just for grins, lets try bypassing the normal
feed diode. In other words, leave the alternate
feed switch open and short around the normal
feed diode.
Bob . . .
Message 9
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Open source product development for OBAM aircraft |
BASIC, COBOL, assembler, C++++, reminds me of a heated debate many years ag
o regarding the merits of octal vs hex. -Of course all these things are t
ools, and you use the tool that is most appropriate for the job at hand.
-But if your only tool is hammer then everything looks like a nail.
Another famous debate was on the use of the GOTO statement. -Everybody kn
ows that the GOTO is very bad. -I am proud to say that I once assisted in
the development of a system that completely eliminated the GOTO. -It was
based on the COMEFROM -statement and also the FISH stack. -COMEFROM
-has fallen out of favor recently, but the FISH stack is still widely use
d: first in, still here. -The system was implemented as a SNOBOL preproce
ssor for a structured JOVIAL compiler. -Sadly it never caught on.
My native language is FORTRAN, which is very useful because you can write F
ORTRAN in any language. -Nostalgia aint what it used to be.
Jim
PS The most useful assembler statement is XPI, execute programmer immediate
.
Message 10
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Open source product development for OBAM aircraft |
Interesting. -The octal vs. hex debate didn't last long, did it? -The r
eason these two were invented was to get away from too many 1s and 0s, i.e.
binary. -There are only 10 types of people in this world - those who und
erstand binary and those who don't.=0A=0AHenador Titzoff=0A=0A=0A=0A_______
_________________________=0A From: rez <rrr.cavu@yahoo.com>=0ATo: aeroelect
ric-list@matronics.com =0ASent: Tuesday, April 17, 2012 10:32 PM=0ASubject:
AeroElectric-List: Re: Open source product development for OBAM aircraft
=0A =0A=0ABASIC, COBOL, assembler, C++++, reminds me of a heated debate man
y years ago regarding the merits of octal vs hex. -Of course all these th
ings are tools, and you use the tool that is most appropriate for the job a
t hand. -But if your only tool is hammer then everything looks like a nai
l.=0A=0AAnother famous debate was on the use of the GOTO statement. -Ever
ybody knows that the GOTO is very bad. -I am proud to say that I once ass
isted in the development of a system that completely eliminated the GOTO.
-It was based on the COMEFROM -statement and also the FISH stack. -CO
MEFROM -has fallen out of favor recently, but the FISH stack is still wid
ely used: first in, still here. -The system was implemented as a SNOBOL p
reprocessor for a structured JOVIAL compiler. -Sadly it never caught on.
=0A=0AMy native language is FORTRAN, which is very useful because you can w
rite FORTRAN in any language. -Nostalgia aint what it used to be.=0A=0AJi
m=0A=0APS The most useful assembler statement is XPI, execute programmer im
========================
Message 11
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Open source product development for OBAM aircraft |
I don't know what you use for board layout, but if you use something like Eagle from http://www.cadsoftusa.com/ the layout connections will always agree with the schematic since they are linked.
They have a freeware version that is complete and only limited by the layers (2
allowed) and the board size (100 x 80 mm) - neither of which is a limit to most
of us. If you pay $69 you can use the
same program to make boards that you can sell. There are other levels that allows
progressively more (up to 16 layers and 4m x 4m size).
I use it at home for home projects and we have one of the professional multi-user
copies at my business.
Highly recommended!
Dick Tasker
Robert L. Nuckolls, III wrote:
>
> The ECB layout is done. I'll put it down for a few
> hours and then 'proof' it against the schematic.
>
> I'll publish the ECB layout and schematic as soon
> as I've confirmed their agreement.
>
>
> Bob . . .
>
>
--
Please Note:
No trees were destroyed in the sending of this message. We do concede, however,
that a significant number of electrons may have been temporarily inconvenienced.
--
Message 12
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Open source product development for OBAM |
aircraft
At 10:03 PM 4/17/2012, you wrote:
><retasker@optonline.net>
>
>I don't know what you use for board layout, but if you use something
>like Eagle from http://www.cadsoftusa.com/ the layout connections
>will always agree with the schematic since they are linked.
I use ExpressPCB which does have a schematic capture
feature. Never did like the looks of their schematics.
I grew up with ARRL publications. the look, feel and
smell of their publications symbols became part of my
DNA.
Also cut my teeth on ECB layouts with little reels of
black, red and blue tape and donuts. All the time
I was putting parts on the board, I was working out
the mechanics of heat sinking, current density,
vibration resistance, ergonomics of the wiring,
etc.
Auto-routers don't mesh well with that train of thought.
So I still enjoy doing the layout "by mouse" with
design goals aforethought. Going thought the schematic
one trace and component at a time is when I cull
the schematic for bugs. At HBC, we had guys to do
layouts for us but they didn't know much, if anything,
about the mechanics of the end-product. But it did made sense
for big, complex boards. I'm more comfortable somewhere
between tape-n-dots and full up schematic capture
with autorouting.
Bob . . .
Message 13
INDEX | Back to Main INDEX |
PREVIOUS | Skip to PREVIOUS Message |
NEXT | Skip to NEXT Message |
LIST | Reply to LIST Regarding this Message |
SENDER | Reply to SENDER Regarding this Message |
|
Subject: | Re: Looking for suggestions |
ok will try these things after work tomorrow. Thanks, Dan=0A=0A=0A=0A>_____
___________________________=0A> From: "Robert L. Nuckolls, III" <nuckolls.b
ob@aeroelectric.com>=0A>To: aeroelectric-list@matronics.com =0A>Sent: Tuesd
ay, April 17, 2012 7:29 PM=0A>Subject: Re: AeroElectric-List: Re: Looking f
Nuckolls, III" <nuckolls.bob@aeroelectric.com>=0A>=0A>At 09:24 PM 4/16/2012
, you wrote:=0A>=0A>We need to do some experiments to see where the noise
=0A>is getting into the system.=0A>=0A>When you CAN hear the noise, is it a
ffected by the=0A>volume control on the radio?=0A>=0A>Does your transmitter
have a side-tone feature,=0A>in other words, can you hear yourself in the
=0A>headphones when you talk on the transmitter?=0A>=0A>Does the noise go a
way when you transmit?=0A>=0A>If I recall correctly, the noise does go away
=0A>when you close the alternate feed switch to=0A>the e-bus.=0A>=0A>Just f
or grins, lets try bypassing the normal=0A>feed diode. In other words, leav
e the alternate=0A>feed switch open and short around the normal=0A>feed dio
==================0A>=0A>=0A>=0A>=0A>=0A>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|