Today's Message Index:
----------------------
0. 12:08 AM - A List Contribution - It's Your Personal Squelch Button... (Matt Dralle)
1. 06:31 AM - Re: Minimizing audio interference (user9253)
2. 10:22 AM - Matronics Email Disruption Fixed... (Matt Dralle)
3. 10:27 AM - How does the Cessna Ground pwr socket work? (Carlos Trigo)
4. 11:07 AM - Re: Re: Minimizing audio interference (Robert L. Nuckolls, III)
5. 02:06 PM - Re: How does the Cessna Ground pwr socket work? (Robert L. Nuckolls, III)
6. 02:19 PM - Re: How does the Cessna Ground pwr socket work? (Robert L. Nuckolls, III)
7. 04:03 PM - Re: How does the Cessna Ground pwr socket work? (Carlos Trigo)
8. 06:47 PM - Replacement Crimpers (Bill_Higdon)
9. 11:44 PM - Re: Re: Minimizing audio interference (Bob Verwey)
Message 0
| 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: | A List Contribution - It's Your Personal Squelch Button... |
There is an automatic "squelch button" of sorts for the Fund Raiser messages.
Here's how it works... As soon as a List member makes a Contribution through
the Matronics Fund Raiser web site, their email address is automatically added
to this year's Contributor List and they instantly cease to receive further Fund
Raiser messages for the rest of the month! Its just that simple! :-)
I really do appreciate each and every one of your individual Contributions to support
the Lists. It is your support that enables me to upgrade the hardware
and software that are required to run a List Site such as this one. It also goes
to pay for the commercial-grade Internet connection and to pay the huge electric
bill to keep the computer gear running and the air conditioner powered
on. I run all of the Matronics Email List and Forums sites here locally which
allows me to control and monitor every aspect of the system for the utmost in
reliably and performance. Your personal Contribution matters because, when combined
with other Listers such as yourself, it pays the bills to keep this site
up and running. I accept exactly ZERO advertising dollars for the Matronics
Lists sites. I can't stand the pop-up ads and all other commercials that are
so prevalent on the Internet these days and I particularly don't want to have
it on my Email List sites.
If you appreciate the ad-free, grass-roots, down-home feel of the Matronics Email
Lists, please make a Contribution to keep it that way!!
http://www.matronics.com/contribution
or, you can send a personal check to the following address:
Matronics / Matt Dralle
581 Jeannie Way
Livermore, CA 94550
Thank you!
Matt Dralle
Matronics Email List Administrator
[Note that there are certain circumstances where you might still see a Contribution
related message. For example, if someone replies to one of the messages,
when using the List Browse feature, or when accessing List message via the Forum.
The system keys on the given email address and since most of these are anonymous
public access methods, there is no simple way to filter them.]
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: Minimizing audio interference |
I like it that Z15-3.1 shows not only the right way, but also the wrong way to
ground devices. I understand that earphones and microphones should not be grounded
locally, but should only be grounded at the panel end (intercom or radio).
I am a little confused with the engine sensors. Grounding might be different
for different types of sensors and their display (EMS or steam gauge). Some
sensors are grounded automatically by nature of their construction and mounting.
But for sensors that have isolated ground, I assume that the ground wire
should terminate at the EMS or display device and not at the engine case. Of
course always follow the manufactures installation instructions.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=412750#412750
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: | Matronics Email Disruption Fixed... |
Dear Listers,
Starting around midnight this morning 11/11/13, the Matronics Barracuda spam filter
that receives all incoming email from the Internet, developed a problem and
started rejecting all incoming
email. I just got off the phone with the Barracuda technical support and we have
resolved the issue as of 10:15am PST.
If you have posted to any of the Lists during this time, you will need to resend
your email to the respective List.
My apologies for the disruption!
Matt Dralle
Matronics Email List and Forum Administrator
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: | How does the Cessna Ground pwr socket work? |
Gents
Just to be sure on how the Cessna (3-lug) ground power socket works:
I followed figure Z-31A, where the third and thinner lug is connected to one
of the contactor coil's terminal.
Where does that thinner lug on the Cessna female socket gets power to
energize the contactor's coil?
Thanks
Carlos
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 |
|
| Subject: | Re: Minimizing audio interference |
At 08:30 AM 11/11/2013, you wrote:
>
>I like it that Z15-3.1 shows not only the right way, but also the
>wrong way to ground devices. I understand that earphones and
>microphones should not be grounded locally, but should only be
>grounded at the panel end (intercom or radio).
> I am a little confused with the engine sensors. Grounding might
> be different for different types of sensors and their display (EMS
> or steam gauge). Some sensors are grounded automatically by nature
> of their construction and mounting.
Yes. Many oil pressure, oil temperature, CHT, EGT sensors are
guilty of 'local grounding' . . . and for the manner in which they
were originally intended to be used . . . it didnt' matter.
> But for sensors that have isolated ground, I assume that the
> ground wire should terminate at the EMS or display device and not
> at the engine case. Of course always follow the manufactures
> installation instructions.
Oh, absolutely. But absent a end-to-end design goal,
one has to play the DIY integration game. One useful
way to deal with a locally grounded signal source
looks like this:
Emacs!
There are low cost integrated circuits that do the
task of making remote voltage measurements across
hostile environments. Alternatively, one can take all
grounds for the instrument to the crankcase. The same
game is played in audio systems. I did the specification
for design of an intercom system on the Lears that
coupled all stations together by way of a transformer
coupled, twisted pair . . . Intercoms scattered about
the airplane could be grounded locally for power and
control without the worry of noises on the ground-
differences finding their way into the audio.
Bob . . .
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: | Re: How does the Cessna Ground pwr socket work? |
At 12:22 PM 11/11/2013, you wrote:
><trigo@mail.telepac.pt>
>
>Gents
>
>Just to be sure on how the Cessna (3-lug) ground power socket works:
>
>I followed figure Z-31A, where the third and thinner lug is connected to one
>of the contactor coil's terminal.
>
>Where does that thinner lug on the Cessna female socket gets power to
>energize the contactor's coil?
>
>Thanks
>Carlos
That ground power connector has been around
for a very long time . . . it dates back to
WWII or earlier. The latest version MS3506
http://tinyurl.com/nc6ybc3
replaced the earlier version AN2552 back in
the 60s
http://www.pilotshop.rs/media/catalog/product/cache/1/image/128
The 'skinny' pin is smaller because it's not intended
to carry much current . . . generally no more than what's
needed to close the ground power contactor in the airplane.
It's very robust for that current level because ground
power jacks on an airplane take a beating . . . a contact
physically sized for 2A or so wouldn't last long in the
all-weather flight-line fast-moving-line-boy environment.
The real 'magic' of this pin is based on its length.
It's shorter than the other two. As you push a hot plug
into the jack, the two current carrying pins are electrically
engaged before the pilot pin . . . this means that the
power pins cannot be loaded before they are engaged
for carrying the load. Similarly, when you pull the plug,
the pilot pin will break first, open the ground power
contactor and prevent arcing at the power pins should
they happen to be loaded at the break.
Next time you're at an FBO and can take a peek
at their ground power plug . . . I think every one
I've seen had blackened and arc-pitted power contacts.
No doubt damaged by hot-plugging or hot-disconnecting
under load where the supported vehicle did not have
a ground power contactor.
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: How does the Cessna Ground pwr socket work? |
>
>
>Where does that thinner lug on the Cessna female socket gets power to
>energize the contactor's coil?
Oops!! . . . didn't answer the question. The pilot
pin is often jumpered to the (+) power pin right
next to it. In some cases, the ground power source
control panel wants to manage the ground power
contactor in the vehicle so a 3rd wire is
brought back to the source for extra attention.
In any case, the pilot pin gets + voltage from the same
source as the adjacent power pin.
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: | How does the Cessna Ground pwr socket work? |
Thanks Bob
Both explanations were welcome.
Got the general idea and the trick of the designer.
Best
Carlos
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: segunda-feira, 11 de Novembro de 2013 22:19
Subject: Re: AeroElectric-List: How does the Cessna Ground pwr socket work?
--> <nuckolls.bob@aeroelectric.com>
>
>
>Where does that thinner lug on the Cessna female socket gets power to
>energize the contactor's coil?
Oops!! . . . didn't answer the question. The pilot
pin is often jumpered to the (+) power pin right
next to it. In some cases, the ground power source
control panel wants to manage the ground power
contactor in the vehicle so a 3rd wire is
brought back to the source for extra attention.
In any case, the pilot pin gets + voltage from the same
source as the adjacent power pin.
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: | Replacement Crimpers |
Bob,
I need to replace my long serving Paladin crimpers, not due to wear, rather someone
else decided they needed them more than I do. One of my criteria for the
replacement is the use of field swappable dies. Having read your writings on crimpers
for use with the common wire terminals Id like your opinion on the following
dies the first one the Sargent 4100-40 is the leader in my opinion
http://www.stanleysupplyservices.com/sargent-4100-40-insulated-terminal-die-set-10-22awg-double-crimp/p/685-440
The following 2 are both in the same class as far as I can see, and not quite to
the standard of the Sargent. They are the AMP BM-534
http://www.automationdirect.com/static/specs/dinwiring.pdf
and the Paladin PA2035 die set
http://www.tessco.com/products/displayProductInfo.do?sku=420434&eventPage=1
Thanks,
Bill Higdon
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=412861#412861
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: Minimizing audio interference |
Bob N, for us neophytes, please enlighten us on the triangular device in
your sketch.
Best...
Bob Verwey
IO 470 A35 Bonanza ZU-DLW
On 11 November 2013 21:05, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 08:30 AM 11/11/2013, you wrote:
>
>
> I like it that Z15-3.1 shows not only the right way, but also the wrong
> way to ground devices. I understand that earphones and microphones should
> not be grounded locally, but should only be grounded at the panel end
> (intercom or radio).
> I am a little confused with the engine sensors. Grounding might be
> different for different types of sensors and their display (EMS or steam
> gauge). Some sensors are grounded automatically by nature of their
> construction and mounting.
>
>
> Yes. Many oil pressure, oil temperature, CHT, EGT sensors are
> guilty of 'local grounding' . . . and for the manner in which they
> were originally intended to be used . . . it didnt' matter.
>
> But for sensors that have isolated ground, I assume that the ground
> wire should terminate at the EMS or display device and not at the engine
> case. Of course always follow the manufactures installation instructions.
>
>
> Oh, absolutely. But absent a end-to-end design goal,
> one has to play the DIY integration game. One useful
> way to deal with a locally grounded signal source
> looks like this:
>
> [image: Emacs!]
> There are low cost integrated circuits that do the
> task of making remote voltage measurements across
> hostile environments. Alternatively, one can take all
> grounds for the instrument to the crankcase. The same
> game is played in audio systems. I did the specification
> for design of an intercom system on the Lears that
> coupled all stations together by way of a transformer
> coupled, twisted pair . . . Intercoms scattered about
> the airplane could be grounded locally for power and
> control without the worry of noises on the ground-
> differences finding their way into the audio.
>
> Bob . . .
>
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! --
|