Today's Message Index:
----------------------
1. 04:23 AM - Re: Toggle switch keyway convention: up vs. down (mmayfield)
2. 06:07 AM - Re: Re: Toggle switch keyway convention: up vs. down (Bob McCallum)
3. 06:33 AM - Re: Re: Toggle switch keyway convention: up vs. down (Robert L. Nuckolls, III)
4. 07:41 AM - Avionics Grounding Bus vs Tabs (Jared Yates)
5. 08:00 AM - Re: Avionics Grounding Bus vs Tabs (Robert L. Nuckolls, III)
6. 08:05 AM - Re: Re: Toggle switch keyway convention: up vs. down (Jeff Luckey)
7. 11:03 AM - Re: Re: Toggle switch keyway convention: up vs. down (Robert L. Nuckolls, III)
8. 02:48 PM - Re: Toggle switch keyway convention: up vs. down (roee)
9. 06:11 PM - Re: Re: Toggle switch keyway convention: up vs. down (Robert L. Nuckolls, III)
10. 07:08 PM - location of Hall effect sensor (fedico94@mchsi.com)
11. 07:28 PM - Re: Toggle switch keyway convention: up vs. down (roee)
12. 09:02 PM - OT: low voltage bulb base *NOT LAMP HOLDER* (rayj)
13. 10:16 PM - Re: location of Hall effect sensor (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Toggle switch keyway convention: up vs. down |
roee wrote:
> This appears to be a duplicate thread, the above posting being a response to this original thread: http://forums.matronics.com/viewtopic.php?t=79809
>
> The message above has been re-posted to the original thread, and additional subsequent
messages have been posted there.
Yeah. Unfortunately the structure of Matronics Email Lists does that frequently.
It's the price you pay for having a jack-of-all-trades email list. It bugs the
living hell out of me because it often makes it hard to follow a thread chronologically
through all the responses.
--------
Mike
Sydney, Australia
Pitts Model 12 under construction.
"Get your facts first, and then you can distort them as much as you please."
Mark Twain. Writer.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=332463#332463
Message 2
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| Subject: | Re: Toggle switch keyway convention: up vs. down |
One final thought on the keyway issue.
Everyone is referencing the keyway to "on" and "off"=2C but what you suppos
edly are referring to is contacts "open" or "closed". Now when you use a si
mple SPST switch for your mags=2C then contacts "closed" is actually "off"
and contacts "open" is actually "on". That sort of throws all theory about
keyway "on" or "off" out the window. So the correct conclusion would be tha
t you would normally want whatever device you are controlling to be "on" wi
th toggle up and "off" with toggle down and the keyway must be positioned t
o achieve this regardless of which way the keyway must be to do this. The i
mportant consideration is the state of the device with reference to toggle
position and the keyway position's only relevance is to achieve this desire
d end result=2C not whether it is "up" or "down".
Bob McC
> Subject: AeroElectric-List: Re: Toggle switch keyway convention: up vs. d
own
> From: mmayfield@ozemail.com.au
> Date: Wed=2C 2 Mar 2011 04:19:57 -0800
> To: aeroelectric-list@matronics.com
>
om.au>
>
>
> roee wrote:
> > This appears to be a duplicate thread=2C the above posting being a resp
onse to this original thread: http://forums.matronics.com/viewtopic.php?t
=79809
> >
> > The message above has been re-posted to the original thread=2C and addi
tional subsequent messages have been posted there.
>
> Yeah. Unfortunately the structure of Matronics Email Lists does that freq
uently. It's the price you pay for having a jack-of-all-trades email list.
It bugs the living hell out of me because it often makes it hard to follow
a thread chronologically through all the responses.
>
> --------
> Mike
>
> Sydney=2C Australia
>
> Pitts Model 12 under construction.
>
> "=3BGet your facts first=2C and then you can distort them as much as
you please."=3B Mark Twain. Writer.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=332463#332463
>
>
>
>
>
>
>
===========
===========
===========
===========
>
>
>
Message 3
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| Subject: | Re: Toggle switch keyway convention: up vs. down |
>All things being equal, where an industry-wide convention exists,
>whether formal or informal / de facto (e.g. keyway down, I think
>we've now established), then that would be the default first choice.
I don't think I implied that. There is no convention
for mounting switches into the product, only a few standards
for orientation of the keyway for purposes of describing
functionality of any given switch. That can vary from
manufacturer to manufacturer EXCEPT for a preponderance
of respect to some mil-standards. The heavy hitters
like Honeywell, Cutler-Hammer, et. als. got their
growth spurts during WWII. If one intended to
to supply a switch, it WOULD be to a spec This
set some trends but it certainly didn't drive
the whole industry nor did it drive design goals
and outcomes for product.
>And finally, having a mix-and-match hodge-podge throughout would be
>the least desirable, though granted, occasional well-justified
>exceptions to a convention may still exist.
Depends on circuit design requirements. I've seen
test fixtures at Beech that would have had switches
mounted both ways on the same panel. And as others
have noted, in some cases, CONTACTS closed is not
SYSTEM on.
We've seen that not all switch (and CB) manufacturers and product
lines meet that criteria,
the 'criteria' is non-existent . . .
and I would factor that into my component selection process.
How? You would reject some device because of keyway
orientation? How about designing YOUR project
so that orientation doesn't matter and ANY functional
device can be used irrespective of orientation?
Bob . . .
Message 4
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| Subject: | Avionics Grounding Bus vs Tabs |
Is there an electrical benefit to using the D-sub avionics ground bus and 5
wires, beyond the mechanical convenience of saving tabs, and/or dealing with
a situation where there is a long distance from the panel to the forest of
tabs? I have about 24" between the front of the panel and the firewall, and
plenty of tabs. Sorry if this is old news, but I couldn't find it in the
archives or AEC.
Message 5
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| Subject: | Re: Avionics Grounding Bus vs Tabs |
At 10:37 AM 3/2/2011, you wrote:
>Is there an electrical benefit to using the D-sub avionics ground
>bus and 5 wires, beyond the mechanical convenience of saving tabs,
>and/or dealing with a situation where there is a long distance from
>the panel to the forest of tabs? I have about 24" between the front
>of the panel and the firewall, and plenty of tabs.
Then use the firewall tabs. The panel ground is intended for
a convenience of consolidation of lots of wires on the panel.
Things like shield grounds on the panel should STILL consolidate
at or near the system that benefits from shields . . . audio
amps are typical devices. But given short runs for power grounds
and relatively low numbers, the panel ground bus offers no
advantages.
Bob . . .
Message 6
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| Subject: | Re: Toggle switch keyway convention: up vs. down |
Or just buy DT (Double Throw) switches and make the necessary adjustments at
wiring time.
Goes back to that "minimize unique parts count" idea.
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bob
McCallum
Sent: Wednesday, March 02, 2011 05:56
Subject: RE: AeroElectric-List: Re: Toggle switch keyway convention: up vs.
down
One final thought on the keyway issue.
Everyone is referencing the keyway to "on" and "off", but what you
supposedly are referring to is contacts "open" or "closed". Now when you use
a simple SPST switch for your mags, then contacts "closed" is actually "off"
and contacts "open" is actually "on". That sort of throws all theory about
keyway "on" or "off" out the window. So the correct conclusion would be that
you would normally want whatever device you are controlling to be "on" with
toggle up and "off" with toggle down and the keyway must be positioned to
achieve this regardless of which way the keyway must be to do this. The
important consideration is the state of the device with reference to toggle
position and the keyway position's only relevance is to achieve this desired
end result, not whether it is "up" or "down".
Bob McC
> Subject: AeroElectric-List: Re: Toggle switch keyway convention: up vs.
down
> From: mmayfield@ozemail.com.au
> Date: Wed, 2 Mar 2011 04:19:57 -0800
> To: aeroelectric-list@matronics.com
>
<mmayfield@ozemail.com.au>
>
>
> roee wrote:
> > This appears to be a duplicate thread, the above posting being a
response to this original thread:
http://forums.matronics.com/viewtopic.php?t=79809
> >
> > The message above has been re-posted to the original thread, and
additional subsequent messages have been posted there.
>
> Yeah. Unfortunately the structure of Matronics Email Lists does that
frequently. It's the price you pay for having a jack-of-all-trades email
list. It bugs the living hell out of me because it often makes it hard to
follow a thread chronologically through all the responses.
>
> --------
> Mike
>
> Sydney, Australia
>
> Pitts Model 12 under construction.
>
> "Get your facts first, and then you can distort them as much as you
please." Mark Twain. Writer.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=332463#332463
>
>
>
> <B
>
>
>
Message 7
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| Subject: | Re: Toggle switch keyway convention: up vs. |
down
At 11:02 AM 3/2/2011, you wrote:
>Or just buy DT (Double Throw) switches and make the necessary
>adjustments at wiring time.
>
>Goes back to that "minimize unique parts count" idea.
Right on . . .
The ONLY unique parts in toggle switches are (1) spring loaded
on one side only and (2) -1 switches that are single-pole
single-throw; two terminals on the back. When we were selling
switches, we didn't stock the -1 switch because a -3 would
nicely fit the same application.
But it's REALLY important that one understands how all the
proposed parts for your project function. Understanding trumps
conventions, traditions and habits every time.
Bob . . .
Message 8
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| Subject: | Re: Toggle switch keyway convention: up vs. down |
>
> There is no convention
> for mounting switches into the product, only a few standards
> for orientation of the keyway for purposes of describing
> functionality of any given switch.
>
I don't entirely agree. There seem to be multiple conflicting conventions out
there, each with varying prevalence in different areas, hence this discussion.
While there may be no formal standard conventions for mounting orientation in
the form of mil-specs, etc., there do seem to exist de facto standard conventions.
You yourself established one (keyway up) by your statement in the AEC,
which granted is not a formal standards document, but nevertheless is referenced
and adhered to by many amateur aircraft builders. And on the flip side, the
switch specifications themselves from prominent manufacturers do often make
direct references equating the keyway side to "down", which while certainly doesn't
force the system designer to use the switch that way, does imply a de facto
convention (keyway down) to their installation orientation which many system
designers will adhere to, all else being equal, to avoid confusion. I don't
know how commonly that's adhered to in the field of GA, and I'm curious to
find out. I'll survey a few different aircraft types next time I'm at the airport
to satisfy that curiosity.
>
> Depends on circuit design requirements. I've seen
> test fixtures at Beech that would have had switches
> mounted both ways on the same panel. And as others
> have noted, in some cases, CONTACTS closed is not
> SYSTEM on.
>
Yep, as noted, some well-justified exceptions to a convention may exist in a system.
But there too, an exception can often be just as easily avoided. For example,
as has been noted, in many cases one can use a symmetric switch where
one isn't technically needed, and thereby be able to maintain a uniform keyway
orientation convention, as well as minimize unique part count. An example of
this would be a magneto P-lead, where contact closed is system off, versus switching
power to a load, where contact closed is system on. In both cases, use
a three-terminal ON-ON switch instead of the two-terminal ON-OFF switch, and
you can stick to your chosen keyway orientation convention, whatever it might
be. The ON-ON switch might be slightly more expensive, but in this case I would
consider this a good trade-off.
>
> and I would factor that into my component selection process.
>
> How? You would reject some device because of keyway
> orientation?
>
Not as a hard rule, but all else being equal, yes. How? Well, where there does
exist a de facto standard for the contact numbering and the keyway orientation
relative to the contact numbering, then I would favor a component whose specification
conforms to that de facto standard over one that does not. Helps avoid
future confusion such as that created by the early Carling switches, as you
described.
>
> How about designing YOUR project
> so that orientation doesn't matter and ANY functional
> device can be used irrespective of orientation?
>
With few exceptions, yes.
-Roee
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=332549#332549
Message 9
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| Subject: | Re: Toggle switch keyway convention: up vs. down |
At 05:44 PM 3/2/2011, you wrote:
>
>
> >
> > There is no convention
> > for mounting switches into the product, only a few standards
> > for orientation of the keyway for purposes of describing
> > functionality of any given switch.
> >
>
>
>I don't entirely agree. There seem to be multiple conflicting
>conventions out there
. . . if there's more than one and they do not conform to each
other, is this not prima-facie demonstration that no such convention
exists?
Bob . . .
Message 10
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| Subject: | location of Hall effect sensor |
RV9A with SD-20 Alternator
The drawings I have are not specific to location of the Hall Effect Sensor in regards
to this installation. The most precise drawing B & C 410-503 would place
this device at the firewall end of the 10ga wire. Can this device function
properly in located within a few inches of the alternator itself ?
Robert Federhofer fedico94@mchsi.com
Message 11
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| Subject: | Re: Toggle switch keyway convention: up vs. down |
nuckolls.bob(at)aeroelect wrote:
>
> . . . if there's more than one and they do not conform to each
> other, is this not prima-facie demonstration that no such convention
> exists?
>
>
> Bob . . .
No, I don't think it is. Even if there doesn't exist a single universally-adopted
convention, there can still exist one or more conventions that are adopted
within more limited scopes. And it appears to me that that's indeed the case
here.
Anyhow... We don't need to debate the semantics of what constitutes a convention,
nor the merits of employing one. My original query, fundamentally, was about
what non-obvious practical factors may exist to favor one choice over the
other (keyway up vs. down) when the choice appears otherwise arbitrary. And that
question is pertinent whether making the choice on a case-by-case basis or
in adopting a broader convention. The question of whether or not conventions
exist in industry, and whether they're driven by practical considerations or
arbitrary aesthetics if they do exist, is actually ancillary to the core issue.
I wrote my original posting as an inquiry to what was behind the convention
expressed in the AEC, since no further explanation of it was offered there (your
explanation here regarding the Carling switches cleared that up). In retrospect,
I should have phrased my query differently such as to avoid making the
discussion convention-centric.
Anyway, I think I've got the answers I needed. I do appreciate your input.
-Roee
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=332585#332585
Message 12
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| Subject: | OT: low voltage bulb base *NOT LAMP HOLDER* |
do not archive
Does anyone know of a source for the part of a bulb that is the base.
The piece that the glass is mounted into and has the electric contacts
on it.
I'm thinking about fabricating LED replacements for some low volt/DC
incandescent. I know they are for sale but expensive and the process of
removing the glass and the filament to reuse old bases is a pain.
Thanks for any help.
--
Raymond Julian
Kettle River, MN
Message 13
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| Subject: | Re: location of Hall effect sensor |
At 10:02 PM 3/2/2011, you wrote:
>
>RV9A with SD-20 Alternator
>
>The drawings I have are not specific to location of the Hall Effect
>Sensor in regards to this installation. The most precise drawing B
>& C 410-503 would place this device at the firewall end of the 10ga
>wire. Can this device function properly in located within a few
>inches of the alternator itself ?
Any point along the length of the alternator
b-lead is fine.
Bob . . .
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