Today's Message Index:
----------------------
1. 04:57 AM - Why have a switch on ALT Field? ()
2. 07:53 AM - Re: Welding cable (Chris)
3. 09:40 AM - Re: Re: Why have a switch on ALT Field? (Robert L. Nuckolls, III)
4. 10:18 AM - Re: Welding cable (Robert L. Nuckolls, III)
5. 10:20 AM - Re: Why have a switch on ALT Field? (rvg8tor)
6. 10:45 AM - Re: Why have a switch on ALT Field? (Ian)
7. 10:53 AM - Re: Why have a switch on ALT Field? (Robert L. Nuckolls, III)
8. 10:53 AM - Re: Welding cable (Sam Hoskins)
9. 11:14 AM - Re: Re: Welding cable (halbenjamin@optonline.net)
10. 11:27 AM - Hired wire-slingers (Robert L. Nuckolls, III)
11. 12:16 PM - Mounting BATT/START Relays ()
12. 12:24 PM - Re: Re: Welding cable (Robert L. Nuckolls, III)
13. 03:23 PM - Re: Mounting BATT/START Relays (rvg8tor)
14. 04:26 PM - Re: Re: Welding cable (Chris)
Message 1
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Subject: | Why have a switch on ALT Field? |
9/26/2009
Hello Mike and Bob, The recent exchange of postings between the two of you
on the subject of "Why have a switch on ALT Field?" has left me a bit
baffled.
Mike, your question dealt with shutting down an alternator by removing the
electrical source to its FIELD. Figure Z 12 was the starting point for your
question and presumably dealt with externally regulated alternators, but
then you threw in the red herring of shutting down internally regulated
alternators.
Bob, your answer appeared to deal extensively with shutting down an
internally regulated alternator by opening the B LEAD such as in Figure Z
24..
Mike, your response below indicated that you believed, as a result of Bob's
posting, that there was a huge amount of electricity flowing through the
wire to the alternator FIELD circuit in an externally regulated alternator
and that therefore a switch rather than a circuit breaker would be needed to
open that circuit.
"You have given me the data i was looking for, I now understand why the
switch is
needed, it is due to potential high loads."
It is my understanding that:
1) The alternator FIELD wire in an externally regulated alternator only
carries a few amps of electricity.
2) Opening this FIELD wire with either a CB or a switch while electricity is
flowing through this wire generates no huge electrical flow interruption
issue.
3) The alternator B LEAD (in either an internally regulated or externally
regulated alternator) can carry a significant amount of electricity and
interrupting this flow through the B LEAD by opening the B LEAD brings up
the issues that Bob dealt with extensively in his response.
Mike if you will check some of the Z diagrams (Z 9 as well as Z 12 for
example) you will see that there is both a CB and a switch that can
interrupt the electrical flow to the alternator FIELD of an externally
regulated alternator. And this is good. The CB provides the traditional
protection to that wiring and the switch makes it possible to turn on / off
the alternator FIELD as desired with no great concern regarding interrupting
huge amperage flow.
My airplane has both a CB and a switch (as do the Z figures) and the
externally regulated alternator FIELD gets turned off by the switch during
every engine shut down procedure while the engine is still running. Shortly
after the alternator is turned off by the FIELD switch the low voltage light
begins to flash telling me that that warning indication is working. I then
turn on my essential bus** and then turn off the battery master and the
radio master (yes I have one ##) to ensure that my Garmin 430W and my
transponder continue to operate off the battery which is now feeding the
avionics essential bus. The Garmin 430W and the transponder are essential
for me to return to my home field inside the Washington DC SFRA.
Please let me know if I have confused or clarified the issue raised by
Mike's original question.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
**PS: Yes I am aware that there are means of causing this to happen
automatically with a diode, but the guy who wired my panel did not do it
that way and I have been living very happily with what he provided because I
understand the system.
##PS: Again this was given to me (after I paid big money to have the panel
built), but I have access to the avionics that I need via an essential
avionics bus so I have been living very happily with what he provided
because I understand the system.
================================================
Time: 06:49:13 PM PST US
Subject: AeroElectric-List: Re: Why have a switch on ALT Field?
From: "rvg8tor" <rvg8tor@comcast.net>
Bob,
Thank you for the explanation, this really helps me understand the design
better.
I did post your reply on the VAF for all to read. I think this will add to
everyones education.
So if I understand what your post, the gist is that there is potential for
excess
voltage in some situations as to make a CB fail if used to cut the field to
the alternator. I have heard others say CBs are not meant to be switches,
but
at my airline we routinely pull CB on certain items while the airplane sits
between flights for several hours. Things like the radar, TCAS, VSI
indicator.
This use of the CB as a switch happens several times a day for each
aircraft.
It this an accepted practice since these are low voltage items.
You have given me the data i was looking for, I now understand why the
switch is
needed, it is due to potential high loads.
--------
Mike "Nemo" Elliott
RV-8A QB (Fuselage)
Message 2
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Where can you find the anchor brand cable? Any weblinks/supply you can
point to.
Thanks
Chris
RV-10
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Thursday, September 24, 2009 3:54 PM
Subject: Re: AeroElectric-List: Welding cable
At 11:51 AM 9/24/2009, you wrote:
I don't know about the Harbor Freight stuff, but when I was looking for
welding cable, I did find a variety of quality in insulation. Some had an
inner jacket, which I took to be a better quality, and some had not.
Sam
Thanks for reminding me of that Sam. A guy
at a welding store told me that the two-layer
cable lasted longer in the field. Little nicks
in the outer jacket tended to propagate cracks
through to the strands when the cable was flexed/
stretched. By making it two layers, the gap
was a "crack stopper" while the inner layer
maintained environmental integrity.
http://aeroelectric.com/Pictures/Wire/4AWG_Welding_Cable_1.jpg
It seems a logical explanation. Of course,
the cables in our airplanes don't get stretched
across gravel drives and run over by dump-trucks.
The Anchor brand welding cable illustrated above
has an HDPM outer jacket which is revered for
its flexibility and toughness. Here's an excerpt
from a wire catalog describing this insulation.
Emacs!
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
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Subject: | Re: Why have a switch on ALT Field? |
At 08:47 PM 9/25/2009, you wrote:
Bob,
Thank you for the explanation, this really helps me understand the
design better. I did post your reply on the VAF for all to read. I
think this will add to everyone's education.
So if I understand what your post, the gist is that there is
potential for excess voltage in some situations as to make a CB fail
if used to cut the field to the alternator.
That's not the bottom line . . .
We should start with some design goals in mind.
For all of my career in TC and OBAM aircraft,
I've embraced and designed systems that meet
traditional goals for any time, any conditions,
On-0ff control of the engine driven power source(s).
I have heard others say CBs are not meant to be switches, but at my
airline we routinely pull CB on certain items while the airplane sits
between flights for several hours. Things like the radar, TCAS, VSI
indicator. This use of the CB as a switch happens several times a
day for each aircraft. It this an accepted practice since these are
low voltage items.
This isn't about using breakers as switches, it's
about meeting the design goal cited above. The b-lead
breaker on an alternator COULD be used to disconnect
the alternator assuming (A) the alternator is under
control [producing 14 or so volts] and (B) the
breaker is on the panel and pullable [many TC aircraft
have push-only breakers]. The classical control philosophy
for engine driven power sources has been a SWITCH in
reach of the crew that offers control over the field
excitation . . . always a low current, easy-to-manage
task. This task COULD be managed by flipping a switch
-OR- pulling the field supply breaker . . . it's your
choice.
There are other legacy design goals . . . like automatic
and absolute control of the alternator in case of
a failed regulator in an OV runaway condition.
Figure Z-24 is but one of several recipes for success.
When Z-24 was combined with alternators NOT designed
and tested to withstand their own load-dumps that some
builders experienced alternator failures immediately
after turning them off while under load.
You have given me the data I was looking for, I now understand
why the switch is needed, it is due to potential high loads.
No . . . its about dependance on pulling
of a b-lead breaker for the purpose of taking
a runaway alternator off line. This is a shaky
design goal due to the fact that a failed alternator
can deliver 100-200 volts in a runaway condition.
Attempting to do this reliably with a 32-volt rated,
pullable breaker would very likely fail the breaker.
Further, pulling a b-lead breaker to mitigate an
ov condition puts human perception, decision, reaction
delays into the shutdown event. That's never been
embraced by the TC aircraft world that I'm aware
of.
The issues before us are (1) design goals for
control (2) design goals for automatic millisecond-
fast mitigation of an OV event. You can pull a
field breaker for (1) if you wish . . . but NOT
a b-lead breaker for (2).
Bob . . .
Message 4
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At 09:45 AM 9/26/2009, you wrote:
>Where can you find the anchor brand cable? Any weblinks/supply you
>can point to.
>Thanks
>Chris
>RV-10
A local welding supply store will offer Anchor or
a suitable equivalent. Some mention was made of
a "200A inverter cable" from Harbor Freight. While
these wires will probably have enough finely stranded
copper for the task, the question to be asked deals
with temperature characteristics and ruggedness of
the INSULATION. Welding cable produced to an ATSM
specification (as are most if not all American
products) will do the job for you . . .
I searched for Anchor outlets but without success
after 20 minutes or so . . . however, the storefront
where I purchased the pictured sample was offering
Anchor brand cable at the time I bought it. That
was several years ago.
Shop around locally first . . .
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
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Subject: | Re: Why have a switch on ALT Field? |
My design goal is a system that is simple as possible but still meets capacity
and redundancy goals (glass IFR bird). Thankfully I found Z12 and this design
suits my need.
My assumption not mentioned by me so far, is that I will have an alternator that
will have a controllable filed with OV protection, be that with internal or
external regulation. I never thought of controlling the alternator with the "B"
lead. So just looking at the Z12 diagram I pondered whether I needed the switch
for the alternator field, I was looking for way to simplify where I could.
My CB panel will all be in easy reach by my right leg, the CB layout has 4 breakers
at the end of two rows to make then stand out from the rest, I also plan
to have them with colored collars, this would make finding them in the dark easy.
Two at the end of the top row are for the primary and standby alternator
fields. Two at the end of the next row control 12V power to the L/R P-mags respectfully.
Also the two rows are not the same length, this also allows for identification
in the dark. Top row is shorter, last two breakers are MAIN ALT
then STBY ALT, easy to remember easy to find.
I know a toggle switch will be faster to actuate than finding a breaker but not
by much. So would elimination of the switch change the design goal of Z12, would
I not still have a controllable engine driven power source? I guess from
what I have read so far the answer is no. Even though the switch will be used
very little, it is still required?
--------
Mike "Nemo" Elliott
RV-8A QB (Fuselage)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=265125#265125
Message 6
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Subject: | Re: Why have a switch on ALT Field? |
OK, now here's one more vote for "confused". I thought the circuit
breaker was supposed to be rated at the output amperage of the
alternator because it's that current that one wants to limit. My 40A
circuit breaker would do nothing for me on the alternator field circuit.
As I understand it, the switch is on the alternator field low-current
12V line (called IGN on my alternator) and the circuit breaker protects
the output side (B lead). Mine is wired this way because it made
sense.
Ian Brown,
RV-9A, Bromont, QC
On Sat, 2009-09-26 at 07:53 -0400, bakerocb@cox.net wrote:
>
> 9/26/2009
>
> Hello Mike and Bob, The recent exchange of postings between the two of you
> on the subject of "Why have a switch on ALT Field?" has left me a bit
> baffled.
>
> Mike, your question dealt with shutting down an alternator by removing the
> electrical source to its FIELD. Figure Z 12 was the starting point for your
> question and presumably dealt with externally regulated alternators, but
> then you threw in the red herring of shutting down internally regulated
> alternators.
>
> Bob, your answer appeared to deal extensively with shutting down an
> internally regulated alternator by opening the B LEAD such as in Figure Z
> 24..
>
> Mike, your response below indicated that you believed, as a result of Bob's
> posting, that there was a huge amount of electricity flowing through the
> wire to the alternator FIELD circuit in an externally regulated alternator
> and that therefore a switch rather than a circuit breaker would be needed to
> open that circuit.
>
> "You have given me the data i was looking for, I now understand why the
> switch is
> needed, it is due to potential high loads."
>
> It is my understanding that:
>
> 1) The alternator FIELD wire in an externally regulated alternator only
> carries a few amps of electricity.
>
> 2) Opening this FIELD wire with either a CB or a switch while electricity is
> flowing through this wire generates no huge electrical flow interruption
> issue.
>
> 3) The alternator B LEAD (in either an internally regulated or externally
> regulated alternator) can carry a significant amount of electricity and
> interrupting this flow through the B LEAD by opening the B LEAD brings up
> the issues that Bob dealt with extensively in his response.
>
> Mike if you will check some of the Z diagrams (Z 9 as well as Z 12 for
> example) you will see that there is both a CB and a switch that can
> interrupt the electrical flow to the alternator FIELD of an externally
> regulated alternator. And this is good. The CB provides the traditional
> protection to that wiring and the switch makes it possible to turn on / off
> the alternator FIELD as desired with no great concern regarding interrupting
> huge amperage flow.
>
> My airplane has both a CB and a switch (as do the Z figures) and the
> externally regulated alternator FIELD gets turned off by the switch during
> every engine shut down procedure while the engine is still running. Shortly
> after the alternator is turned off by the FIELD switch the low voltage light
> begins to flash telling me that that warning indication is working. I then
> turn on my essential bus** and then turn off the battery master and the
> radio master (yes I have one ##) to ensure that my Garmin 430W and my
> transponder continue to operate off the battery which is now feeding the
> avionics essential bus. The Garmin 430W and the transponder are essential
> for me to return to my home field inside the Washington DC SFRA.
>
> Please let me know if I have confused or clarified the issue raised by
> Mike's original question.
>
> 'OC' Says: "The best investment we can make is the effort to gather and
> understand knowledge."
>
>
> **PS: Yes I am aware that there are means of causing this to happen
> automatically with a diode, but the guy who wired my panel did not do it
> that way and I have been living very happily with what he provided because I
> understand the system.
>
> ##PS: Again this was given to me (after I paid big money to have the panel
> built), but I have access to the avionics that I need via an essential
> avionics bus so I have been living very happily with what he provided
> because I understand the system.
>
> ================================================
>
>
> Time: 06:49:13 PM PST US
> Subject: AeroElectric-List: Re: Why have a switch on ALT Field?
> From: "rvg8tor" <rvg8tor@comcast.net>
>
>
> Bob,
>
> Thank you for the explanation, this really helps me understand the design
> better.
> I did post your reply on the VAF for all to read. I think this will add to
> everyones education.
>
> So if I understand what your post, the gist is that there is potential for
> excess
> voltage in some situations as to make a CB fail if used to cut the field to
> the alternator. I have heard others say CBs are not meant to be switches,
> but
> at my airline we routinely pull CB on certain items while the airplane sits
> between flights for several hours. Things like the radar, TCAS, VSI
> indicator.
> This use of the CB as a switch happens several times a day for each
> aircraft.
> It this an accepted practice since these are low voltage items.
>
> You have given me the data i was looking for, I now understand why the
> switch is
> needed, it is due to potential high loads.
>
> --------
> Mike "Nemo" Elliott
> RV-8A QB (Fuselage)
>
>
>
>
>
Message 7
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Subject: | Re: Why have a switch on ALT Field? |
At 06:53 AM 9/26/2009, you wrote:
<Snip>
Please let me know if I have confused or clarified the issue raised
by Mike's original question.
Your words appear to paint a clear understanding . . .
The problem with this (and many threads of similar discussion
in the past) is the stirring of a LOT of simple-ideas (facts)
into one pot of ill-conceived stew (no definition of design
goals) and stirred over a hot fire ("don't do that or you're
gonna die") with the unbridled enthusiasm (mis-interpretation
of words).
'OC' Says: "The best investment we can make is the effort to gather
and understand knowledge."
Yup, you got that right. I notice that my response to Mike's
follow-up hasn't passed through the server yet . . . but
I hope it proves to be a useful clarification of how we . . .
(1) start with design goals . . .
(2) then craft an architecture that addresses design
goals while . . .
(3) eliminating single points of failure for extra ordinarily
useful electro-whizzies as revealed by skillfully
conducted FMEA.
(4) Study and understand the specs for ingredients that go
into recipes for success.
(5) Select style, quality and a minimized quantity of components
that go into the proposed recipe.
(6) Verify that the recipe meets design goals.
(7) Analyze subsequent failures to deduce root cause.
Wear out? Mis-application? Robustness? Quality?
Error of stating or conformance to design goals?
Other? Answers to these questions may prompt a program
review that goes all the way back to step (1).
When one makes a career of this process, you eventually
discover that it's a Mobius Loop which strives for archiving
a host of lessons-learned while improving upon the best we
know how to do. This is the essence of good design engineering
as I've come to understand it.
Its interesting but frustrating that there are so many
pitfalls that put the 7-step process at risk. We're
fortunate that until recently, loss of the entire
electrical system was unlikely to force an airplane
down.
Now that we've embraced performance advantages of modern
electronics to control engines, there's a pressing
need to craft an architecture with particular attention
to step (3). This is relatively easy to do if the
seven steps are dutifully observed . . . but it's
easy to be distracted from the process if
excited rhetoric borne out of misunderstanding
dominates the tenor of the discussion.
So while we "gather and understand knowledge" (become
designers) we must be ready to calmly defuse
excitement with lucid explanation of simple-ideas
and how they become ingredients that go into recipes
for success (become teachers).
Bob . . .
Message 8
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Subject: | Re: Welding cable |
I was at my local True-Value hardware store, this morning, and they had the
4AWG inner jacketed stuff. I didn't look for the brand name, though.
Sam
On Sat, Sep 26, 2009 at 12:13 PM, Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> nuckolls.bob@aeroelectric.com>
>
> At 09:45 AM 9/26/2009, you wrote:
>
>> Where can you find the anchor brand cable? Any weblinks/supply you can
>> point to.
>> Thanks
>> Chris
>> RV-10
>>
>
> A local welding supply store will offer Anchor or
> a suitable equivalent. Some mention was made of
> a "200A inverter cable" from Harbor Freight. While
> these wires will probably have enough finely stranded
> copper for the task, the question to be asked deals
> with temperature characteristics and ruggedness of
> the INSULATION. Welding cable produced to an ATSM
> specification (as are most if not all American
> products) will do the job for you . . .
>
> I searched for Anchor outlets but without success
> after 20 minutes or so . . . however, the storefront
> where I purchased the pictured sample was offering
> Anchor brand cable at the time I bought it. That
> was several years ago.
>
> Shop around locally first . . .
>
>
> Bob . . .
>
> ---------------------------------------
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ---------------------------------------
>
>
Message 9
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Subject: | Re: Welding cable |
Hi Bob,
West Marine carries ANCOR brand battery cable. I don't know if it's any good. Just
another piece of intel to muck things up.
Hal Benjamin
RV4 Long Island, NY
----- Original Message -----
From: "Robert L. Nuckolls, III"
Subject: RE: AeroElectric-List: Welding cable
> III"
>
> At 09:45 AM 9/26/2009, you wrote:
> >Where can you find the anchor brand cable? Any weblinks/supply
> you
> >can point to.
> >Thanks
> >Chris
> >RV-10
>
> A local welding supply store will offer Anchor or
> a suitable equivalent. Some mention was made of
> a "200A inverter cable" from Harbor Freight. While
> these wires will probably have enough finely stranded
> copper for the task, the question to be asked deals
> with temperature characteristics and ruggedness of
> the INSULATION. Welding cable produced to an ATSM
> specification (as are most if not all American
> products) will do the job for you . . .
>
> I searched for Anchor outlets but without success
> after 20 minutes or so . . . however, the storefront
> where I purchased the pictured sample was offering
> Anchor brand cable at the time I bought it. That
> was several years ago.
>
> Shop around locally first . . .
>
>
> Bob . . .
>
> ---------------------------------------
> ( . . . a long habit of not thinking )
> ( a thing wrong, gives it a superficial )
> ( appearance of being right . . . )
> ( )
> ( -Thomas Paine 1776- )
> ---------------------------------------
>
>
>
>
>
>
>
Message 10
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Subject: | Hired wire-slingers |
>>##PS: Again this was given to me (after I paid big money to have the panel
>>built), but I have access to the avionics that I need via an essential
>>avionics bus so I have been living very happily with what he provided
>>because I understand the system.
The task of selecting a panel builder is two-fold. Unfortunately,
features that drive most buy-decisions are appearance (craftsmanship),
and experience (built a lot of panels). The the seven-step
process I described earlier goes to the MOST important component
of the buy-decision process . . . and is seldom offered by some
of the most skilled builders.
This is why the most successful airplane companies had
good engineers that teamed with equally good craftsmen
that were both free to continuously improve upon the
best we know how to do. I always had a excellent relationship
with the folks in the factory. I hold their skills
in high regard . . . I've worked on those lines too.
But corporate management is moving from self-serving
entrepreneurs to stockholder-serving bankers. Product
quality and capability is being wrenched from the
control of designers and craftsmen and replaced with
process and control dictates (ISO, FAR, EPA, etc).
The result is predictable and inevitable. The best
we know how to do is no longer represented by the
folks who understood and built airplanes most of us
learned to fly in. The best we know how to do is
now in your basements and garages.
Fortunately, there are many skilled craftsmen from
the TC aircraft world who are supporting OBAM aircraft
. . . but their skills and understanding as
designers are carry-overs from their experience
in the TC aircraft world. Great amounts of
money CAN buy great amounts of mediocre work product.
This is avoided when a team of artful designers AND craftsmen
filter the activity through the Seven Steps.
You are all program managers now . . . managers
who have to design, craft, do make-buy decisions and
ultimately climb into and fly the work product.
While "caveat emptor" was mostly applied to the exchange
of real estate, it's no less applicable here.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 11
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Subject: | Mounting BATT/START Relays |
9/26/2009
Hello Mike, You wrote: "........ this does not seem like a big deal to me as
they are fairly long lasting devices."**
I began my real plane aviation career as a US Navy airplane mechanic some 59
years ago. Since then I have spent thousands of hours working on airplanes,
acquired an A&P rating, a Master's Degree in Aeronautical Engineering, built
my own airplane, and flown several thousand hours.
I had plenty of opportunity during that time to confront many
maintainability issues. These issues come in many different forms, but one
of the most important ones is accessibility -- if you can't access a part
you can't fix it, adjust it, or replace it.
It is very easy in the early stages of building a homebuilt to significantly
underestimate the effort that will be required to access a part when the
airplane is completed.
I want you to envision your airplane completed and someone someday
attempting to remove and replace one of the contactors which is held in
place by through bolts also holding the other contactor in place on the
other side of the firewall. It will require a wrench simultaneously on both
the bolt head and the bolt nut. This means that two people will be required.
One of those persons must dive down under the instrument panel -- not always
an easy task (take it from an old man). What frequently happens when
building the airplane is that one is able to use both hands on the part
being worked on. When diving down under the instrument panel sometimes only
one hand can reach the part. Realize also that some fairly heavy guage wires
must be disconnected.
Then on reinstall both contactors must be in alignment for the holding bolts
to go through and wires must be reconnected.
Mounting the contactors with anchor nuts can turn this into a one man job
and reduce the time and effort significantly.
'OC' Says: "The best investment we can make is the effort to gather and
understand knowledge."
**PS: I am aware locally of three that have failed just in the last few
years.
=============================================
Time: 07:13:11 AM PST US
Subject: AeroElectric-List: Mounting BATT/START Relays
From: "rvg8tor" <rvg8tor@comcast.net>
My battery will be just aft of the firewall so the battery relay will be
mounted
on the aft side of the firewall, the start relay will be just opposite on
the
forward side of the firewall. I see some who install plate nuts to mount
these
relays individually, 4 nuts + 4 bolts+4 holes in the firewall. The holes
on the two relays work out so that one could just use 2 bolts and two normal
nuts
(not anchor nuts) and mount the two relays through common holes in the
firewall.
The only drawback I can see is that if one or the other needs to be replaced
then both you can't remove one without disturbing the other, this does not
seem like a big deal to me as they are fairly long lasting devices. Can
anyone
see why my idea is a bad one? I though of heat transfer from the hot side
of the firewall, but bolts into nut plates would do that to some degree, and
all of the relays could be mounted forward of the firewall like many factory
airplanes have them.
--------
Mike "Nemo" Elliott
RV-8A QB (Fuselage)
Message 12
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Subject: | Re: Welding cable |
At 01:00 PM 9/26/2009, you wrote:
>Hi Bob,
>
>West Marine carries ANCOR brand battery cable. I don't know if it's
>any good. Just another piece of intel to muck things up.
>
Thanks for the heads-up. I checked a portion of
their offerings at:
http://tinyurl.com/ycmabhn
It's not clear to me that this is the same "Anchor"
cable company. The material illustrated has tinned
conductors while welding cable does not. Further,
their prices (before shipping I presume) are pretty
breathtaking. Higher than 22759 stuff from Aircraft
Spruce!
It seems that 'Anchor' is an exceedingly popular
name for various brands/businesses. Makes it
difficult to find 'the one' . . .
Here's one good hit
http://tinyurl.com/ydjdlr2
assuming you can use 500' of 4awg. This stuff
is about $1.50/ft before shipping. This is how
your welding supply store would buy it and sell
it for $2.25/ft or so . . .
It appears that the folks we're looking for
offer a huge selection of electric and wire-welding
parts and tools of which welding cable is only
a small fraction of their catalog. Given this
penetration into the welding supplies market,
it's quite likely that local stores will know
all about them.
If anyone finds the mother website for Anchor
brand welding products, I'd appreciate hearing
about it.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 13
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Subject: | Re: Mounting BATT/START Relays |
BAKEROCB,
All very good points. I do try to look at future maintenance when I am building
my airplane. One of the reasons I am putting my battery just aft of the firewall
is I will have easy access to it via the front baggage area for charging
or jumping if it goes dead, it is also a more hospitable environment for the
battery.
I can get to both sides of the bolts holding the relays because the front baggage
door gives access. The only limiting factor I have now made for myself is
if the battery relay is the only thing I needed to replace then I would not have
to remove the cowl if I had used nut plates. My thought at this point is I
can always go that route in the future, for now I like the fact that I have two
less holes in the firewall. See my log for pictures of the completed installation,
done yesterday.
http://www.mykitlog.com/users/display_log.php?user=rvg8tor&project=403&category=0&log=88927&row=1
--------
Mike "Nemo" Elliott
RV-8A QB (Fuselage)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=265145#265145
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Well I guess you see why I asked, I spent some time googling and didn't find
much whioch actually called out the epdm insulation. Guess I should have
mentioned that. I did find this place and I sent an email to ask what
brand it is they carry, hopefully they will respond Monday and I'll report
back. Its finding that EPDM insulation that seems tricky, I had some stuff
locally but it had a paper inner liner and I didn't find the outer stuff to
be very tough, it seemed easy to nick and penetrate.
http://www.wesbellwireandcable.com/Welding.html
-Chris
RV-10
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Saturday, September 26, 2009 3:20 PM
Subject: Re: RE: AeroElectric-List: Welding cable
At 01:00 PM 9/26/2009, you wrote:
Hi Bob,
West Marine carries ANCOR brand battery cable. I don't know if it's any
good. Just another piece of intel to muck things up.
Thanks for the heads-up. I checked a portion of
their offerings at:
http://tinyurl.com/ycmabhn
It's not clear to me that this is the same "Anchor"
cable company. The material illustrated has tinned
conductors while welding cable does not. Further,
their prices (before shipping I presume) are pretty
breathtaking. Higher than 22759 stuff from Aircraft
Spruce!
It seems that 'Anchor' is an exceedingly popular
name for various brands/businesses. Makes it
difficult to find 'the one' . . .
Here's one good hit
http://tinyurl.com/ydjdlr2
assuming you can use 500' of 4awg. This stuff
is about $1.50/ft before shipping. This is how
your welding supply store would buy it and sell
it for $2.25/ft or so . . .
It appears that the folks we're looking for
offer a huge selection of electric and wire-welding
parts and tools of which welding cable is only
a small fraction of their catalog. Given this
penetration into the welding supplies market,
it's quite likely that local stores will know
all about them.
If anyone finds the mother website for Anchor
brand welding products, I'd appreciate hearing
about it.
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
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