Today's Message Index:
----------------------
1. 02:46 AM - Circuit breaker polarity (Greg Young)
2. 06:01 AM - Re: Circuit breaker polarity (rampil)
3. 08:52 AM - Re: Mono Isolation Amp - Where to get circuit board? (Robert L. Nuckolls, III)
4. 09:03 AM - Re: Voltage drop under load (Robert L. Nuckolls, III)
5. 11:06 AM - Re: Circuit breaker polarity (Robert L. Nuckolls, III)
6. 12:54 PM - Dumb questions (MaxNr@aol.com)
7. 01:20 PM - Power Board on EBay (h&jeuropa)
8. 01:26 PM - LEDs at 24volts? (Dawson-Townsend,Timothy)
9. 02:06 PM - Re: Dumb questions (jon@finleyweb.net)
10. 02:25 PM - Re: Dumb questions (Richard Girard)
11. 02:56 PM - Re: LEDs at 24volts? (rampil)
12. 03:01 PM - Z13-8 N error ? (Jeff Page)
13. 06:22 PM - LEDs at 24volts? (Ralph Hoover)
14. 07:38 PM - Re: Z13-8 N error ? (Robert L. Nuckolls, III)
15. 08:08 PM - Re: Circuit breaker polarity (Greg Young)
16. 08:10 PM - TNC connections (Jeffrey W. Skiba)
17. 10:09 PM - Z13-8 N P-Mags (Jeff Page)
Message 1
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Subject: | Circuit breaker polarity |
I am rewiring my Navion panel using busses with Potter-Brumfield W31 switch
breakers and Klixon 7277 c/b's. I put the P-B buss bar on the bottom
following their Load-Line labeling but put the Klixon bar on top to ease
access to the load terminals. My IA neighbor (not my supervising IA) tried
to tell me it was backward but I had already checked and there is no
labeling on the Klixon c/b's. I see no intuitive reason it should care about
polarity but then I don't have a real understanding of their inner workings.
Did I miss something? Does polarity matter for the Klixons? If so, I can
change my buss. If not, why does P-B label their units (it's also on their
W23 c/b's?) Is it real or just a case of eliminating choice? Thanks for the
education.
Regards,
Greg Young
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Subject: | Re: Circuit breaker polarity |
Breakers have no polarity. Element heating occurs in either
direction!
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=160648#160648
Message 3
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Subject: | Re: Mono Isolation Amp - Where to get circuit board? |
At 04:55 AM 1/24/2008 -0800, you wrote:
><capav8r@gmail.com>
>
>I am adding a second radio to a plane that has no room for a full audio
>panel without making a whole new panel. I am going to route two coms and
>one marker beacon to the intercom. I have speced out the switched and
>dome a wiring diagram. I looked at the Isolation Amp at the AeroElectric
>web site. However, under parts, I don't see where I can order the circuit
>board to make the amp (part no 9009-301-2A).
>
>Where do I get one?
I've had a lot of requests for this
item and I'm in the process of placing
it back on the website order form. I'll
try to get this done in the next few days.
I've been out of town for a week and have
some taller fires to beat down first.
Bob . . .
Message 4
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Subject: | Re: Voltage drop under load |
At 06:52 PM 1/24/2008 -0500, you wrote:
>
>Yes voltage starts to sag as the alternator output starts to lag demand.
>Quick math suggests that your alternator is working properly. (100 watts
>divided by 13.3 volts is about 7.5 amps per 100 watt load) My alternator
>can handle all loads but the voltage will drop a bit if I pull the
>throttle to idle on approach. No big deal if the battery helps out for a
>few dozen seconds on final approach. In cruise my taxi lights wig wag
>which halves the current draw.
>Ken
>
>Bill Bradburry wrote:
>><bbradburry@bellsouth.net>
>> I noticed today that my voltage would drop from about 14.5 volts down to
>>13.3 volts when I turned all my lights on. That is two 100W landing, two
>>100W taxi, position, and strobe lights.
>>I made sure that I had plenty of rpm to be certain that the alternator was
>>putting out its max. The alternator is rated at 55A.
>>Is it possible that I am pulling more amps than the alternator can handle?
>>Is the drop of voltage an indicator of this?
>>What should be the size of the B lead wire for a 55A alternator?
>>Thanks,
>>Bill B
13.3 is TOO low. You need to put a temporary lead wire
on the alternator's b-lead terminal and bring it into
the cockpit for attaching a voltmeter. You MAY find that
the alternator voltage at the b-lead is holding up just
fine and that your wiring is too small . . . i.e. accounts
for the drops under load that you've observed.
I recommend 4AWG minimum for all the "fat" wires in
the airplane. There's so little of it that weight deltas
are insignificant . . . but 4AWG or larger makes for
very solid voltage regulation at all loads.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 5
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Subject: | Re: Circuit breaker polarity |
At 04:39 AM 1/27/2008 -0600, you wrote:
>I am rewiring my Navion panel using busses with Potter-Brumfield W31
>switch breakers and Klixon 7277 c/b's. I put the P-B buss bar on the
>bottom following their Load-Line labeling but put the Klixon bar on top to
>ease access to the load terminals. My IA neighbor (not my supervising IA)
>tried to tell me it was backward but I had already checked and there is no
>labeling on the Klixon c/b's. I see no intuitive reason it should care
>about polarity but then I don't have a real understanding of their inner
>workings. Did I miss something? Does polarity matter for the Klixons? If
>so, I can change my buss. If not, why does P-B label their units (it's
>also on their W23 c/b's?) Is it real or just a case of eliminating choice?
>Thanks for the education.
Intuitively, the physics of a series-connected
heat-tripped, switch do not suggest a reason why
the breaker would care which way electrons flow
through it . . . and in particular, AC system
breakers where electrons are known to turn around
and run the other direction 120 times a second!
You've already had some good responses but I'll
take this opportunity to elaborate. Not all
breakers are rudimentary . . . i.e. a simple
spring-loaded, heater-tripped latch holding a
set of single or double-break contacts closed.
Breakers can be had with auxiliary switches,
indicator lights, voltage sense coils, and
all manner of enhancements where proper function
of the enhancement depends on a connection to
power being available even when the breaker is
open. Obviously, some third terminal is necessary
for an enhancement to function, this is sometimes
an obvious connection, or perhaps it gets hooked
up through the mounting.
In any case, it's not uncommon for a manufacturer
to use common tooling to mold a breaker housing
for all versions, hence you often see the word
"load", "line" or both formed right next to the
breaker's terminals . . .
I've asked several tech reps for breakers and
except for enhanced breakers, orientation in
the system doesn't matter. Interestingly enough,
if an electrician encounters "line" and/or "load"
labels on a breaker, he'll wire it up that way
whether it matters or not. And I suspect many
aviation techs do too . . . not because the
physics matters but because some inspector who
doesn't know any better can be counted on to
insist that the protocols be followed.
The only time I've encountered this as a
"problem" is when a builder finds it convenient
to fabricate a two-row bus-bar and take load
feeders off opposite ends of the breaker. When
they come stamped with a breaker rating,
they look pretty funky with one row upside-down
in their holes!
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 6
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I have been sitting in the back row on this list, hoping to learn something.
I was born without any electronic genes. I am building an all metal light
sport plane.(Zenith) Right or wrong, I developed the habit (over five decades of
personal, military and commercial flying) of listening to broadcast radio on
the ADF. I'm thinking that I need to install an of the shelf automobile radio in
my project. No second hand Ebay ADF's. My two questions are: Will I fry the
radio if I use only a headset and no speakers? About the antenna. I know that I
should mount it vertically, but it must withstand airspeed excursions to Vne
(156kts/180mph) without going L shaped. I've come up with somehow jamming it
inside the canopy, or insulating it and mounting against the landing gear, or
inside some kind of tubular mast on the belly. I did come across a NOS
Volkswagen telescoping antenna in my shop. It would be great if that Lyc carburetor
turns up again the same way. Somebody stop me if I'm on the wrong track. This
isn't the most pressing problem out there, but all suggestions are appreciated.
Bob Dingley
**************
Start the year off right. Easy ways to stay in
shape.
http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
Message 7
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Subject: | Power Board on EBay |
Check out Item # 120215336354 or search for "Power Board" for an auction for a
Blue Mountain Avionics Power Board.
Jim Butcher
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=160699#160699
Message 8
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Subject: | LEDs at 24volts? |
I have my reasons, so let's not get into that, but we're building a
24/28 volt airplane.
Question: Can I take an LED with built-in resistor for 12 volt
operation (as bought at Radio Shack) and run it at 24 volts? On the
bench it seems to operate fine. Even if it reduces LED life somewhat,
with the insane life that LEDs have anyway, and an application as
warning light that is intermittant at best, maybe it will do fine.
Thoughts?
TDT
RV-10
40025
Message 9
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=0AHi Bob,=0A=0A =0A=0AMight I suggest you take a look at satellite radio -
like XM (http://www.xmradio.com) or Sirius? I've been flying with an XM s
etup (Roady XL) and love it. I can move it from car to airplane to house o
r listen on my computer/Internet, in-flight station reception doesn't fade
out every 15 minutes (as I fly away from a station), and the antenna is a l
ittle tiny thing that is mounted inside my airplane (zero drag). It does r
equire a subscription so is not free. In my plane, I just connect the radi
o output to my intercom music input.=0A=0A =0A=0AJon=0A=0A=0A-----Original
Message-----=0AFrom: MaxNr@aol.com=0ASent: Sunday, January 27, 2008 3:49pm
=0ATo: aeroelectric-list@matronics.com=0ASubject: AeroElectric-List: Dumb q
uestions=0A=0AI have been sitting in the back row on this list, hoping to l
earn something. I was born without any electronic genes. I am building an a
ll metal light sport plane.(Zenith) Right or wrong, I developed the habit (
over five decades of personal, military and commercial flying) of listening
to broadcast radio on the ADF. I'm thinking that I need to install an of t
he shelf automobile radio in my project. No second hand Ebay ADF's. My two
questions are: Will I fry the radio if I use only a headset and no speakers
? About the antenna. I know that I should mount it vertically, but it must
withstand airspeed excursions to Vne (156kts/180mph) without going L shaped
. I've come up with somehow jamming it inside the canopy, or insulating it
and mounting against the landing gear, or inside some kind of tubular mast
on the belly. I did come across a NOS Volkswagen telescoping antenna in my
shop. It would be great if that Lyc carburetor turns up again the same way.
Somebody stop me if I'm on the wrong track. This isn't the most pressing p
roblem out there, but all suggestions are appreciated.=0ABob Dingley =0A
Message 10
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Subject: | Re: Dumb questions |
Bob, I'm no expert, but I did learn this from one. Some automotive audio
systems use completely separate grounds for each channel. For that you'd
have to rewire your headphones and run three jacks instead of two. This info
may be old, it was a few years ago and things move on, but it never hurts to
ask the sales guy or look at the wiring layout of any system you're thinking
of buying.
Rick
On Jan 27, 2008 2:49 PM, <MaxNr@aol.com> wrote:
> I have been sitting in the back row on this list, hoping to learn
> something. I was born without any electronic genes. I am building an all
> metal light sport plane.(Zenith) Right or wrong, I developed the habit (over
> five decades of personal, military and commercial flying) of listening to
> broadcast radio on the ADF. I'm thinking that I need to install an of the
> shelf automobile radio in my project. No second hand Ebay ADF's. My two
> questions are: Will I fry the radio if I use only a headset and no speakers?
> About the antenna. I know that I should mount it vertically, but it must
> withstand airspeed excursions to Vne (156kts/180mph) without going L shaped.
> I've come up with somehow jamming it inside the canopy, or insulating it and
> mounting against the landing gear, or inside some kind of tubular mast on
> the belly. I did come across a NOS Volkswagen telescoping antenna in my
> shop. It would be great if that Lyc carburetor turns up again the same way.
> Somebody stop me if I'm on the wrong track. This isn't the most pressing
> problem out there, but all suggestions are appreciated.
> Bob Dingley
>
>
> **************
> Start the year off right. Easy ways to stay in shape.
> http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
>
> *
>
> *
>
>
Message 11
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Subject: | Re: LEDs at 24volts? |
LED Resistor exist to limit the current flow through the LED.
You did not mention want kind of 24v supply you used to test your
12v LED with, I wonder if it had high internal resistance.
Your safest bet is to add a serial resistor, otherwise the lifetime of the
LED may be VERY short
Ira
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=160713#160713
Message 12
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Reading through the docs on E-Mag and P-Mag products, I think the
wiring as shown on Z13-8 version N is incorrect.
First, the labels are switched. The P-Mag is the one with the
internal power generator.
Second, the wiring for the real P-Mag I believe is incorrect.
As shown, in the center test position, the P-lead, pin 4 is grounded
and the battery bus is applied to pin 5. The engine should stop if
the P-lead is grounded and it is not possible to test the internal
power generator if there is power externally applied.
Keep the wiring all the same, but specify the switch as S700-2-1 and I
think it should be correct.
Jeff Page
Dream Aircraft Tundra #10
Message 13
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Subject: | LEDs at 24volts? |
If you know or measure the current of the LED at 12 V you can divide 12
by the current and obtain the correct series resistor to maintain the
same current at 24. Assuming about 20ma for a run of the mill led you
would get 600 ohms. 12V across 600 ohms will dissipate .24W so a 1/2
watt resistor would be in order. You will probably find that if the LED
doesn't fail at 24V it's series resistor may!! You will find either 560
or 620 ohm resistors are common values and either would work.
--
Ralph C. Hoover
RV7A
hooverra at verizon dot net
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Subject: | Re: Z13-8 N error ? |
At 05:56 PM 1/27/2008 -0500, you wrote:
>
>Reading through the docs on E-Mag and P-Mag products, I think the
>wiring as shown on Z13-8 version N is incorrect.
>
>First, the labels are switched. The P-Mag is the one with the
>internal power generator.
>
>Second, the wiring for the real P-Mag I believe is incorrect.
>As shown, in the center test position, the P-lead, pin 4 is grounded
>and the battery bus is applied to pin 5. The engine should stop if
>the P-lead is grounded and it is not possible to test the internal
>power generator if there is power externally applied.
>Keep the wiring all the same, but specify the switch as S700-2-1 and I
>think it should be correct.
I checked the drawings again and they are correct as
published. The P-Mag is wired to the main bus. This
lets you do the occasional "test" of the internal alternator
by shutting down the main bus while the engine is running.
This is easy to do by configuring the system to the
ENDURANCE MODE where flight is sustained with only the E-bus
and battery-bus hot. Emagair suggests this test be conducted
infrequently . . . about as often as you would test the
ENDURANCE MODE of operation for your electrical system.
Emagair's drawings do not exploit this feature unique to
Z-13/8 . . . and it should not. The vast majority of their
customers will not be using Z-13/8. I hope that the majority
of my customers ARE using Z-13/8.
The E-mag is wired to run from the always-hot battery bus.
A means by which power can be removed from the ignition
system at shutdown is necessary. Hence the double-pole, three-
position, progressive transfer switch offers independent
control of E-Mag power and ONLY AFTER the E-mag has been shut
down by means of grounding pin 4 (control) has been suggested.
This particular architecture was crafted to support AeroElectric
Connection philosophy for having all electrically dependent engine
functions run from a battery bus. This goes toward a design
goal that allows shutting down the entire electrical system
with minimal (if not zero) influence on engine operations.
Since the E-Mag needs power, it has been wired to the battery
bus. The P-Mag is internally powered and needs only occasional
tests of its internal power operations . . . which is easy to do
when wired as shown by combing the ignition tests with any
ENDURANCE MODE tests one might choose to conduct on the
rest of the system.
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 15
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Subject: | Circuit breaker polarity |
>
> In any case, it's not uncommon for a manufacturer
> to use common tooling to mold a breaker housing
> for all versions, hence you often see the word
> "load", "line" or both formed right next to the
> breaker's terminals . . .
That's likely. There are a bunch of P-B series that use the same case.
>
> I've asked several tech reps for breakers and
> except for enhanced breakers, orientation in
> the system doesn't matter. Interestingly enough,
> if an electrician encounters "line" and/or "load"
> labels on a breaker, he'll wire it up that way
> whether it matters or not. And I suspect many
> aviation techs do too . . . not because the
> physics matters but because some inspector who
> doesn't know any better can be counted on to
> insist that the protocols be followed.
It just happened that the labeling on the P-B's matched my preferred bus bar
mounting. The Klixon row below it has the bar on the opposite terminals
which then looked wrong to the "do it the standard way and don't ask why"
crowd.
> The only time I've encountered this as a
> "problem" is when a builder finds it convenient
> to fabricate a two-row bus-bar and take load
> feeders off opposite ends of the breaker. When
> they come stamped with a breaker rating,
> they look pretty funky with one row upside-down
> in their holes!
>
> Bob . . .
>
Thanks for reaffirming my choices. Insightful as always.
Regards,
Greg Young
Message 16
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Okay,
I am having a hard time finding the comic book or other type simple guide to
making TNC connections.
Is there such a creature at aeroelectic?
I found the one for bnc
http://www.aeroelectric.com/articles/bnccrimp.pdf
is the tnc similar?
I ask since my Garmin 430 was converted to the new Garmin 430W and that GPS
antenna has a tnc connector.
Thanks in advance.
Jeff.
Message 17
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You might think wiring up an electronic mag might be simple :-(
Replacing the S700-2-10 with a S700-2-1 as I indicated in my previous
post isn't the correct solution. It does allow removing external
power to test the internal alternator, but in normal use, it removes
external power before grounding the P-Lead, which is clearly stated by
E-Mag as not the way to shut down the engine :-(
At one point I had the design such that I used only three switches to
control power/ground to the mags, allowing testing and with a position
to engage the starter.
However, it used three expensive switches and I have encountered
poorer reliability with spring return types. The main problem really,
is that the power to both mags was routed through one single switch.
Since it is not being moved in flight, it is unlikely to fail, but ..
My current plan is to use four of the simplest single-pole on-off
switches, two for power and two for p-lead grounding, plus a push
button for start. So that is a total of five switches, but much
simpler and cheaper components and the plane will still fly if any one
of them fails.
I like the simple flow of operating the switches. However, I am not
completely comfortable without a keyswitch, which would be difficult
to include in this design. I do not like keyswitches, but there is a
clear delineation between someone being (or not) permitted to start
the aircraft if they are in possession of the key. To prevent
starting, the key would need to disconnect mag power to avoid hand
propping. The secret switch under the dash, used for auto anti-theft
is a safety of flight issue. Anyone have any good ideas how to handle
this ?
Jeff Page
Dream Aircraft Tundra #10
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