Today's Message Index:
----------------------
1. 04:34 AM - Control Stick Switch Override (Bruce Gray)
2. 06:00 AM - KX-155A on 12V machine (Gianni Zuliani)
3. 06:59 AM - Re: ELT batteries (DWENSING@aol.com)
4. 07:24 AM - Re: B-lead fuse vs. circuit breaker (Phil Birkelbach)
5. 08:30 AM - Re: personal ELT (Robert L. Nuckolls, III)
6. 08:33 AM - Re: personal ELT (Robert L. Nuckolls, III)
7. 08:37 AM - Re: ELT batteries (Robert L. Nuckolls, III)
8. 08:43 AM - Re: KX-155A on 12V machine (Robert L. Nuckolls, III)
9. 08:50 AM - Re: B-lead fuse vs. circuit breaker (Robert L. Nuckolls, III)
10. 10:04 AM - Audio Isolation Amplifier Problem (Jordan Grant)
11. 10:11 AM - Question on Z-13 & firewall penetration ('Scott Richardson')
12. 02:00 PM - Re: Manual master switch (Robert L. Nuckolls, III)
13. 02:29 PM - Re: ELT batteries (Richard McCraw)
14. 03:32 PM - Re: personal ELT (AI Nut)
15. 04:00 PM - Re: diodes on relay coils (Robert L. Nuckolls, III)
16. 04:08 PM - Re: Flap circuit relay questions (Robert L. Nuckolls, III)
17. 05:14 PM - Re: Manual master switch (Kevin Klinefelter)
18. 05:36 PM - Re: Manual master switch (Richard E. Tasker)
19. 06:04 PM - Re: Manual master switch (Mark C. Milgrom)
20. 06:15 PM - Re: Manual master switch (Ned Thomas)
21. 06:32 PM - Single or Dual batteries?? (Carl Morgan - ZK-VII)
22. 08:20 PM - Re: ELT batteries (James E. Clark)
23. 08:57 PM - XCOM, Pilot, Lightspeed and customer service. (Rob W M Shipley)
24. 09:10 PM - Re: XCOM, Pilot, Lightspeed and customer service. (John Slade)
Message 1
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| Subject: | Control Stick Switch Override |
--> AeroElectric-List message posted by: "Bruce Gray" <Bruce@glasair.org>
Hi Bob,
As promised, after attending the Groton, CT seminar, I still have a
question.
With the plethora of trim, PTT, and other control buttons being
duplicated on each control stick, I'm looking for a circuit to provide
for pilot priority/override if there is a tug of war between the
pilot/copilot. I need to handle 2 axis trim, speed brakes, and CWS.
Bruce
www.glasair.org
-
Message 2
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| Subject: | KX-155A on 12V machine |
--> AeroElectric-List message posted by: "Gianni Zuliani" <gianni@comgz.com>
Hi Bob,
would you provide one of your valuable hints to tackle my present problem:
I've got a nice KX-155A (28V only King NAV-COM) which I want to install on
my new Stag-Ez which is a 12V, single batt, single alt. machine.
Is there a viable/efficient and reliable way that you know and might
suggest? If necessary, I would be willing to install a second battery and
even a second alternator... a 28V power supply being the last resource
(Aeromation? or whichever you might recommend).
Thank you.
Gianni Zuliani
Message 3
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| Subject: | Re: ELT batteries |
--> AeroElectric-List message posted by: DWENSING@aol.com
In a message dated 3/7/04 9:26:44 PM Eastern Standard Time, rmccraw@wcvt.com
writes:
> Re when to change out flashlight batteries in ELTs: As I think about it,
> you
> may well be right about changing out the batteries before the expiration,
>
Instructions with new ACK says to change them with each Annual Inspection. It
also gives the specific "D" cell to be used.
Dale Ensing
Message 4
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| Subject: | Re: B-lead fuse vs. circuit breaker |
--> AeroElectric-List message posted by: "Phil Birkelbach" <phil@petrasoft.net>
Well said, but don't forget that to use the circuit breaker you have to
bring that big noisy wire all the way through the firewall up to the panel
and then back to the battery. If you use a fuse then you can mount
everything forward of the firewall and not bring it into the cabin at all.
Unless of course your battery is inside but you can still keep it away from
the panel, where the radios are.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Baffles / Cowling
http://www.myrv7.com
----- Original Message -----
From: "Dan Branstrom" <danbranstrom@verizon.net>
Subject: Re: AeroElectric-List: B-lead fuse vs. circuit breaker
> --> AeroElectric-List message posted by: "Dan Branstrom"
<danbranstrom@verizon.net>
>
> Somebody will state this better (and correct me if I'm wrong): The circuit
> breaker has a low amount of resistance because it depends on the heating
of
> a bi-metallic strip, which bends and trips the breaker, and heat = use of
> energy. A fuse has an even lower amount of resistance, because the heat
> produced by current flowing through it rises much faster at the limit of
its
> ability to carry that current. Since the fuse doesn't heat up much until
it
> gets close to the limit, it has a much lower resistance.
>
> To smooth out the noise of the alternator, you want the lowest resistance
> possible. With a low resistance, there is less possibility for minor
> fluctuations (noise) to occur, because more of the fluctuations from the
> alternator are absorbed by the battery. If you put a resister between the
> two of them, there is more possibility for a voltage differential between
> the alternator and the battery. The more voltage difference (particularly
> from a pulse) the more noise you will get.
>
> Dan Branstrom
> ----- Original Message -----
> From: "Roger Evenson" <revenson@comcast.net>
> To: <aeroelectric-list@matronics.com>
> Subject: AeroElectric-List: B-lead fuse vs. circuit breaker
>
>
> > --> AeroElectric-List message posted by: "Roger Evenson"
> <revenson@comcast.net>
> >
> > In Chapter 17, Bob suggests a B-lead fuse instead of a circuit breaker,
> "for a much lower resistance..between alternator (the noisiest device) and
> battery (the best filter)."
> >
> > Why? What's this mean? What's the significance of this design feature?
> >
> > Thanks for answering this beginner's question. Roger.
> >
> >
>
>
Message 5
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:25 PM 3/7/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: "Richard McCraw" <rmccraw@wcvt.com>
>
>Re when to change out flashlight batteries in ELTs: As I think about it, you
>may well be right about changing out the batteries before the expiration,
>maybe at the halfway point or some such. For the record, I'll check with my
>A&P tomorrow and post the info.
>
>Sorry for any misinformation: I'll try to straighten it out.
>
>Rick McCraw
If they are alkaline batteries, you can (from an engineering
perspective) leave them in place until their "sell by" dates
on the battery. Alkalines are extremely long lived. From
the bureaucratic perspective, there may be something different.
If its a certified device, there should be instructions for
maintaining air worthy status which would state the manufacturer's
FAA approved routine for battery maintenance.
Bob . . .
Message 6
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 12:12 AM 3/7/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: "James E. Clark"
><james@nextupventures.com>
>
>Comment below ..
>
>[SNIP]
>
> >
> > Forgive me if this detail has been mentioned before (I'm new to the list),
> > but there exist TSO'd ELTs that use off-the-shelf batteries -- D-cells, I
> > think. I have such an ELT in my Bonanza.
> >
> > All you have to do is use batteries that carry an expiration date and
> > replace them before they expire. Makes battery replacement a whole lot'
>
>Bill I don't have the regs before me on this (so I **may** be WRONG!) but I
>think you might want to double check that on the batteries.
>
>We are in the middle of condition inspection on our RV6 and changed out out
>D-cells. The ones we took out had not expired and theones we put in expire
>in 2011! It is probably not a good idea to leave those things in there for
>much beyond a year (let alone 7) as they might corrode and fail you JUST
>when you need them.
Inspections for corrosion should be part of a yearly routine
for inspection . . . if they're clean and bright, there's
no practical justification for tossing an alkaline cell just
because it's been setting there "too long". Alkaline cells
have very long shelf lives.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Message 7
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| Subject: | Re: ELT batteries |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:59 AM 3/8/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: DWENSING@aol.com
>
>In a message dated 3/7/04 9:26:44 PM Eastern Standard Time, rmccraw@wcvt.com
>writes:
>
>
> > Re when to change out flashlight batteries in ELTs: As I think about it,
> > you
> > may well be right about changing out the batteries before the expiration,
> >
>
>Instructions with new ACK says to change them with each Annual Inspection. It
>also gives the specific "D" cell to be used.
That stops any arguments right dead in their tracks . . . no?
Bob . . .
Message 8
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| Subject: | Re: KX-155A on 12V machine |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 02:58 PM 3/8/2004 +0100, you wrote:
>--> AeroElectric-List message posted by: "Gianni Zuliani" <gianni@comgz.com>
>
>Hi Bob,
>would you provide one of your valuable hints to tackle my present problem:
>I've got a nice KX-155A (28V only King NAV-COM) which I want to install on
>my new Stag-Ez which is a 12V, single batt, single alt. machine.
>Is there a viable/efficient and reliable way that you know and might
>suggest? If necessary, I would be willing to install a second battery and
>even a second alternator... a 28V power supply being the last resource
>(Aeromation? or whichever you might recommend).
There are 14 to 28v step-up supplies. One suited to your
application is about $450. It's the AmeriKing AK550-6
Bob . . .
Message 9
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| Subject: | Re: B-lead fuse vs. circuit breaker |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 04:04 PM 3/6/2004 -0700, you wrote:
>--> AeroElectric-List message posted by: "Roger Evenson"
><revenson@comcast.net>
>
>In Chapter 17, Bob suggests a B-lead fuse instead of a circuit breaker,
>"for a much lower resistance..between alternator (the noisiest device) and
>battery (the best filter)."
>
>Why? What's this mean? What's the significance of this design feature?
The battery is the best filter in the airplane but it's effectiveness is
limited by the TOTAL wiring resistance between alternator and battery
-AND- where busses attach to the system to get power. Bringing the
alternator into the cabin to power the same bus that radios would
like to see "clean" voltage doesn't make much sense. There is nothing
magic or useful in having a breaker on the panel to protect the
alternator b-lead. Tying the alternator onto system fat wires under
the cowl is how they do it in big airplanes, no reason we shouldn't
do it in little airplanes too. The major advantage of the main bus
breaker is being able to accommodate the battery ammeter which was
popular from day one in cars and carried over into airplanes in the
late 40s . . . Once we decide to do diagnostics with instruments
other than a battery-ammeter, the system gets simpler, quieter,
and you don't bring another high current (highly magnetized) wire
into the cockpit where it adds no value and may detract.
Bob . . .
-----------------------------------------
( Experience and common sense cannot be )
( replaced with policy and procedures. )
( R. L. Nuckolls III )
-----------------------------------------
Message 10
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| Subject: | Audio Isolation Amplifier Problem |
--> AeroElectric-List message posted by: "Jordan Grant" <gra9933@bellsouth.net>
Bob and everyone else:
I recently hooked up my intercom and audio-iso amp and began to test it
and
I have a problem.
Here is a description of my system:
My Audio Iso Amp is the Bob Knuckolls standard - built as the Monophonic
version. The VHF radio COM out is connected to one input. My engine monitor
(ACS2002) audio output is connected to another input. These are the only two
inputs to the Audio Iso Amp. The output of the Amp goes to the Comm Input on
a Flightcom 403 intercom. My CD player is connected to the music inputs on
the Flightcom.
My problem:
The volume of the COMM radio and the ACS2002 is very low when listening
on
the intercom. I can hear it, but its very quiet. The music volume and
intercom volume are fine. When I bypass the Audio Iso Amp with either the
COMM radio or the ACS2002 audio, the volume is fine. If I directly wire BOTH
the COMM audio and the ACS2002 to the Flightcom's input (bypassing the Audio
Iso Amp), I again can hear both, but they are very quiet.
I need to try some other combinations to troubleshoot, I think. In the
meantime, I was hoping someone might have an idea of whats messed up.
Thanks,
Jordan Grant
RV-6 Wiring, wiring, wiring, wiring....
Message 11
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| Subject: | Question on Z-13 & firewall penetration |
--> AeroElectric-List message posted by: "'Scott Richardson'" <scott_m_richardson@sbcglobal.net>
Hi,
I'm wiring up my Lancair 235 using Z-13 with the battery in the rear of
the aircraft (behind the passenger seat). I had some questions:
1. The diagram shows the main fusebox being connected to the output
side of the battery connector. I'm assuming that I could connect it
either there or at the starter contactor end, correct? (This just saves
another run of #4 cable to the rear of the aircraft). Would there be
any problem of taking that feed somewhere in the middle of the run of #2
cable? - say near where it passes the instrument panel?
2. Is there any problem using a brass bolt to pass the + side current
through the firewall? I would use a phenolic ring around the bolt to
isolate the (grounded) firewall stainless from the bolt.
3. Is it better to have the ANL on the forward or rear side of the
firewall? Does the ANL smoke at all when it "blows"?
4. I'm about to order some #2 welding cable but am trying to plan my
runs in the meantime. Can someone give me an idea of how flexible it is
- i.e. what's typical for a minumum bend radius?
Thanks as always.
Scott
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Scott M Richardson scott_m_richardson@sbcglobal.net
Message 12
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| Subject: | Re: Manual master switch |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:12 PM 3/7/2004 -0600, you wrote:
>--> AeroElectric-List message posted by: "David Carter"
><dcarter@datarecall.net>
>
>Was reviewing the "manual battery switch" issue tonight and reviewed this
>old e-mail.
>
>Ref David S's comment below, "If you have to mount it a distance from the
>battery in order
> > to reach it, you are compromising the crash safety that the master
>disconnect provides."
>
>I had also thought of that - but IF I put a ANL current limiter (BIG fuse)
>within 1 to 5 inches of the positive battery terminal, and then run a fat
>wire up to the instrument panel to the manual switch, even though the fat
>wire is longer than 5-6 inches, it is NOT "unprotected", so, should meet the
>guidelines that Bob Nuckolls frequently reminds us of.
>
>So, I/we should be able to mount the battery up close to firewall - out of
>reach (and not back by our knee) - 'cause we no longer have to have the
>manual battery switch near the battery.
Please don't do this. If you want to reduce battery contactor
drain, consider some of the modern contactors with two-stage
solenoids. They draw the typical 1A to close but less than
0.1A to maintain contact.
You can use a manual battery switch and operate it remotely
via a bowden cable (like the choke control on older cars).
Crash safety is dependent upon limiting the energy that can
be taken from battery powered wires when the metal is getting
crunched. The FAA calls for 5a as a limiting value (breaker
is okay with them, a fuse is MUCH better). A long wire with
an ANL limiter in it falls WAAAYYYYY out side spirit and
intent of either (1) positive disconnect of wire by pilot
using battery contactor and/or relays local to the battery
bus or limiting the protection of long, always-hot wires
to 5A or less.
Bob . . .
Message 13
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--> AeroElectric-List message posted by: "Richard McCraw" <rmccraw@wcvt.com>
Regarding alkaline battery replacement: My IA believes the regs are
ambiguous. He thinks there's a reading that would allow you to leave them
in right up until expiration. However, why would you want to? He believes
in replacing them annually and letting the old ones make light for the rest
of their little lives.
Sounds reasonable to me, and -- as was my original point -- way, way cheaper
than using proprietary batteries.
Message 14
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| Subject: | Re: personal ELT |
--> AeroElectric-List message posted by: "AI Nut" <ainut@earthlink.net>
Of course, one could alway put a meter on it and see what the voltage reads.
That will tell you it's current condition and whether it is 50% gone or not.
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: RE: AeroElectric-List: personal ELT
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 12:12 AM 3/7/2004 -0500, you wrote:
> >--> AeroElectric-List message posted by: "James E. Clark"
> ><james@nextupventures.com>
> >
> >Comment below ..
> >
> >[SNIP]
> >
> > >
> > > Forgive me if this detail has been mentioned before (I'm new to the
list),
> > > but there exist TSO'd ELTs that use off-the-shelf batteries --
D-cells, I
> > > think. I have such an ELT in my Bonanza.
> > >
> > > All you have to do is use batteries that carry an expiration date and
> > > replace them before they expire. Makes battery replacement a whole
lot'
> >
> >Bill I don't have the regs before me on this (so I **may** be WRONG!) but
I
> >think you might want to double check that on the batteries.
> >
> >We are in the middle of condition inspection on our RV6 and changed out
out
> >D-cells. The ones we took out had not expired and theones we put in
expire
> >in 2011! It is probably not a good idea to leave those things in there
for
> >much beyond a year (let alone 7) as they might corrode and fail you JUST
> >when you need them.
>
> Inspections for corrosion should be part of a yearly routine
> for inspection . . . if they're clean and bright, there's
> no practical justification for tossing an alkaline cell just
> because it's been setting there "too long". Alkaline cells
> have very long shelf lives.
>
>
> Bob . . .
>
> -----------------------------------------
> ( Experience and common sense cannot be )
> ( replaced with policy and procedures. )
> ( R. L. Nuckolls III )
> -----------------------------------------
>
>
Message 15
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| Subject: | Re: diodes on relay coils |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:53 AM 3/5/2004 -0600, you wrote:
>--> AeroElectric-List message posted by: "David Swartzendruber"
><dswartzendruber@earthlink.net>
>
>
> >
> > In a message dated 3/5/2004 8:37:21 AM Eastern Standard Time,
> > dswartzendruber@earthlink.net writes:
> > Suppression devices on a relay coil can only slow down the release of
> > the relay contacts. The goal is to suppress the transient enough to
> > protect the control switch contacts without degrading the performance
>of
> > the relay. That is why some prefer not to use just a diode, but will
> > put a zener in series with the diode, or use an MOV or transorb.
> >
> > Dave
> > No, Dave, I have always understood that the objective is to provide an
> > alternate current path for the relay coil's flux to be relieved. A
>device
> > that
> > accomplishes this the fastest is best. With no suppression device at
>all,
> > the
> > opening control contacts impede the quick discharge of the coil's
>energy
> > and that
> > energy burns the opening contacts. Any suppression device will speed
> > things
> > up over the high resistance of open (or opening) control contacts.
>Right?
> > Please tell me if I am all wet here!
> >
> > John P. Marzluf
> > Columbus, Ohio
> > Kitfox Outback (out back in the garage)
> >
>
>Yes, the suppression device provides an alternate path for the coil
>current. Without it, the stored energy in the inductive coil winding is
>dissipated as arcing across the contacts of the control switch. With
>it, the energy is dissipated in the suppression device because the
>voltage never gets high enough to arc across the switch contacts. The
>higher the voltage across the suppression device, the faster the energy
>is dissipated and the faster the coil current decays. The key to fast
>release of the relay contacts is fast decay of the coil current. This
>is because the coil current is what is creating the magnetic flux that
>is holding the relay contacts closed. Adding a diode across the coil of
>a relay slows it down because it slows down the decay of the coil
>current.
>
>Bob has determined that the diode on the coil does not slow the opening
>of the relay contacts significantly enough to have an effect on relay
>performance. Personally, I have no data to back up a statement
>concerning how much the relay performance is affected by the diode vs.
>no diode vs. a transorb, MOV, or Zener.
Okay, here's the data. We're talking about two different
characteristics of relays that are only slightly inter-related.
(1) Drop out delay: Time it takes from opening of coil
excitation circuit until relay contacts first open.
(2) Contact opening time: Time it takes from first motion
of contacts until current through the opening contacts
goes to zero.
The total relay response time is sum of the two values
above.
Take a peek at
http://www.aeroelectric.com/temp/704-1DelayNoDiode.gif
Upper trace is for contacts of 30A rated, S704-1 relay
from B&C while switching a 5A resistive load at 24 VDC.
Lower trace is coil voltage. Note that when coil circuit
opens, we see the classic "spike" followed 2.5 milliSeconds
later with opening of the contacts. Now look at:
http://www.aeroelectric.com/temp//704-1DelayWithDiode.gif
Here we've added the diode and as expected, coil spike
goes away. Further, the delay time from first opening of
coil circuit to opening of contacts is now 12.5 milliSeconds
which means that total response time has indeed moved
out 10 milliseconds or so. Consider this trace:
http://www.aeroelectric.com/temp//704-1OpeningTimeNoDiode.gif
This is a detail of contact opening for S704 relay with
no diode. Here we see that when voltage across the contacts
rises to about 10 volts, a arc forms between the contacts
and continues for about 210 microSeconds or 1/5 milliSecond.
Compare with this trace:
http://www.aeroelectric.com/temp//704-1OpeningTimeWithDiode.gif
Here we see that adding a diode produced an opening time of
230 microSeconds . . . about 20 microSeconds longer than
the case without the diode. One might deduce that adding
a diode did indeed increase length of arc time . . . but if
you repeatedly measure opening time you get a spread of
readings that run 190 to 250 microSeconds with and
without diodes.
This same test has been repeated on smaller and larger relays
with similar results.
What's this mean with respect to how we use relays? Not much.
Contact opening speed is more strongly affected by rapid fall-off
of magnetic attraction to the pole piece than by delayed fall-off
of the magnetic field. So irrespective of the slope of magnetic
field (proportional to current in coil), once the contacts begin
to move, their speed is more a function of the air-gap that builds
between relay armature and the pole-piece of the coil.
If one has a tightly timed system that depends on minimizing
drop out response time of the relay, perhaps an alternative technology
for dealing with coil spike would be useful. When you're punching
a trim switch or operating a flap switch, adding 10 milliSeconds
to opening delay is not significant. Wear and tear on the
relay is a separate issue not related to opening delay. The
diode is a simple, effective means for suppressing coil
spike antagonistic to switches that CONTROL relays. If
you want to mitigate arcing across the opening (or closing)
relay contacts, that's a separate task . . .
I've been working a number of contact wear issues at RAC
over the past two years. I've seen contacts fail that were
very lightly loaded and had minimal or no arcing during
the opening sequence. I'm still picking through the
simple-ideas that define contact physics. For the moment,
making things run well for a long time on the input
side of the relay are unrelated to things that make it
run well for a long time on the output side.
Bob . . .
Message 16
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| Subject: | Re: Flap circuit relay questions |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:43 AM 3/5/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: KITFOXZ@aol.com
>
>Hello Bob,
>
>Re: relay bounce. I always believed that relay bounce was caused by poor
>inductive "kick" suppression. I can swear it was a listed item in my old
>text
>book about relay operation. Years ago, I worked on mechanically tuned
>avionics
>boxes that were the state of the art in our Naval Aircraft. RCA, Collins,
>Bendix, Honeywell and others of the manufacturers used neons to handle
>suppressing the coils on those units. I always assumed the "bounce" I
>would see from
>time to time was caused by the neon not dropping the relay coil's voltage low
>enough between cycles.
No, bounce is totally unrelated to anything you do on the input
side of the relay. Bounce is a VERY important aspect of relay
and switch life. A really bouncy relay or switch can get
two to ten EXTRA contact closures (along with attendant arcing
and metal transfers) for EACH time the switch is operated.
I'm studying a situation where two devices built and tested
to the same specifications have markedly different service
life. Turns out that one bounces typically one time on closure,
the other was 3-7 times.
>Some of those old boxes needed very fast stop pulses to get the mechanical
>mechanisms to halt in just the right spot for accurate tuning. I would
>imagine
>that you are very familiar with this scenerio. (thank God for varactors!)
>
>The neons were used, I assume for their speed. Perhaps the "bounce" I would
>see was in fact caused by worn (burned) contacts on the controlling device --
>not able to give me a clean break at off time? We used to take those suckers
>apart and burnish the contacts as needed. The kids of today don't know half
>of the school of hard knocks that went into producing the modern GPS receiver!
The NE-2 neon-bulb predates silicon rectifiers by about 30 or more
years. It had a strong clamping effect on coil spike voltage when
the gas fired at about 65 volts. Selenium rectifiers were used
for coil spike suppression too. It didn't get really easy until
the silicon rectifier came onto the scene about 1957.
Bob . . .
Message 17
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| Subject: | Manual master switch |
--> AeroElectric-List message posted by: "Kevin Klinefelter" <kevann@gte.net>
Got any links to a "modern contactor with two stage solenoid"? 0.1 A sounds
good for a Rotax 18a alt.
Thanks, Kevin
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L.
Nuckolls, III
Subject: Re: AeroElectric-List: Manual master switch
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
At 11:12 PM 3/7/2004 -0600, you wrote:
>--> AeroElectric-List message posted by: "David Carter"
><dcarter@datarecall.net>
>
>Was reviewing the "manual battery switch" issue tonight and reviewed this
>old e-mail.
>
>Ref David S's comment below, "If you have to mount it a distance from the
>battery in order
> > to reach it, you are compromising the crash safety that the master
>disconnect provides."
>
>I had also thought of that - but IF I put a ANL current limiter (BIG fuse)
>within 1 to 5 inches of the positive battery terminal, and then run a fat
>wire up to the instrument panel to the manual switch, even though the fat
>wire is longer than 5-6 inches, it is NOT "unprotected", so, should meet
the
>guidelines that Bob Nuckolls frequently reminds us of.
>
>So, I/we should be able to mount the battery up close to firewall - out of
>reach (and not back by our knee) - 'cause we no longer have to have the
>manual battery switch near the battery.
Please don't do this. If you want to reduce battery contactor
drain, consider some of the modern contactors with two-stage
solenoids. They draw the typical 1A to close but less than
0.1A to maintain contact.
You can use a manual battery switch and operate it remotely
via a bowden cable (like the choke control on older cars).
Crash safety is dependent upon limiting the energy that can
be taken from battery powered wires when the metal is getting
crunched. The FAA calls for 5a as a limiting value (breaker
is okay with them, a fuse is MUCH better). A long wire with
an ANL limiter in it falls WAAAYYYYY out side spirit and
intent of either (1) positive disconnect of wire by pilot
using battery contactor and/or relays local to the battery
bus or limiting the protection of long, always-hot wires
to 5A or less.
Bob . . .
Message 18
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| Subject: | Re: Manual master switch |
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
Try:
http://www.ciitech.com/doc_generator.asp?doc_id=1280
Dick Tasker, RV9A #90573
Kevin Klinefelter wrote:
>--> AeroElectric-List message posted by: "Kevin Klinefelter" <kevann@gte.net>
>
>Got any links to a "modern contactor with two stage solenoid"? 0.1 A sounds
>good for a Rotax 18a alt.
>
> Thanks, Kevin
>
>
>
>
Message 19
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|
| Subject: | Re: Manual master switch |
--> AeroElectric-List message posted by: "Mark C. Milgrom" <milgrom@earthlink.net>
I saw this contactor featured in "Aviation Week & Space Technology"
magazine recently:
http://www.tycoelectronics.com/prodnews.asp?ID=586
Some claims of this product:
"A standard built-in coil economizer limits coil-holding power to just
1.7 watts at 12VDC. It also limits back EMF to 0V."
"The CAP200 weighs in at just under one pound (.43kg) and measures about
2.58 x 3.17 x 2.85 inches (65.6 x 80.5 x 72.3 mm) tall. It is UL
recognized for the U.S. and Canada (file E208033) and CE marked."
Mark Milgrom
Kevin Klinefelter wrote:
> --> AeroElectric-List message posted by: "Kevin Klinefelter" <kevann@gte.net>
>
> Got any links to a "modern contactor with two stage solenoid"? 0.1 A sounds
> good for a Rotax 18a alt.
>
> Thanks, Kevin
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert L.
> Nuckolls, III
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Manual master switch
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <bob.nuckolls@cox.net>
>
> At 11:12 PM 3/7/2004 -0600, you wrote:
>
>>--> AeroElectric-List message posted by: "David Carter"
>><dcarter@datarecall.net>
>>
>>Was reviewing the "manual battery switch" issue tonight and reviewed this
>>old e-mail.
>>
>>Ref David S's comment below, "If you have to mount it a distance from the
>>battery in order
>>
>>>to reach it, you are compromising the crash safety that the master
>>
>>disconnect provides."
>>
>>I had also thought of that - but IF I put a ANL current limiter (BIG fuse)
>>within 1 to 5 inches of the positive battery terminal, and then run a fat
>>wire up to the instrument panel to the manual switch, even though the fat
>>wire is longer than 5-6 inches, it is NOT "unprotected", so, should meet
>
> the
>
>>guidelines that Bob Nuckolls frequently reminds us of.
>>
>>So, I/we should be able to mount the battery up close to firewall - out of
>>reach (and not back by our knee) - 'cause we no longer have to have the
>>manual battery switch near the battery.
>
>
>
> Please don't do this. If you want to reduce battery contactor
> drain, consider some of the modern contactors with two-stage
> solenoids. They draw the typical 1A to close but less than
> 0.1A to maintain contact.
>
> You can use a manual battery switch and operate it remotely
> via a bowden cable (like the choke control on older cars).
> Crash safety is dependent upon limiting the energy that can
> be taken from battery powered wires when the metal is getting
> crunched. The FAA calls for 5a as a limiting value (breaker
> is okay with them, a fuse is MUCH better). A long wire with
> an ANL limiter in it falls WAAAYYYYY out side spirit and
> intent of either (1) positive disconnect of wire by pilot
> using battery contactor and/or relays local to the battery
> bus or limiting the protection of long, always-hot wires
> to 5A or less.
>
> Bob . . .
>
>
>
>
>
>
>
Message 20
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| Subject: | Re: Manual master switch |
--> AeroElectric-List message posted by: "Ned Thomas" <315@cox.net>
How about a latching solenoid that requires no electrical holding power:
http://www.hotronicsproducts.com/circuit.htm
----- Original Message -----
From: "Kevin Klinefelter" <kevann@gte.net>
Subject: RE: AeroElectric-List: Manual master switch
> --> AeroElectric-List message posted by: "Kevin Klinefelter"
<kevann@gte.net>
>
> Got any links to a "modern contactor with two stage solenoid"? 0.1 A
sounds
> good for a Rotax 18a alt.
>
> Thanks, Kevin
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Robert
L.
> Nuckolls, III
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Manual master switch
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> <bob.nuckolls@cox.net>
>
> At 11:12 PM 3/7/2004 -0600, you wrote:
> >--> AeroElectric-List message posted by: "David Carter"
> ><dcarter@datarecall.net>
> >
> >Was reviewing the "manual battery switch" issue tonight and reviewed this
> >old e-mail.
> >
> >Ref David S's comment below, "If you have to mount it a distance from the
> >battery in order
> > > to reach it, you are compromising the crash safety that the master
> >disconnect provides."
> >
> >I had also thought of that - but IF I put a ANL current limiter (BIG
fuse)
> >within 1 to 5 inches of the positive battery terminal, and then run a fat
> >wire up to the instrument panel to the manual switch, even though the fat
> >wire is longer than 5-6 inches, it is NOT "unprotected", so, should meet
> the
> >guidelines that Bob Nuckolls frequently reminds us of.
> >
> >So, I/we should be able to mount the battery up close to firewall - out
of
> >reach (and not back by our knee) - 'cause we no longer have to have the
> >manual battery switch near the battery.
>
>
> Please don't do this. If you want to reduce battery contactor
> drain, consider some of the modern contactors with two-stage
> solenoids. They draw the typical 1A to close but less than
> 0.1A to maintain contact.
>
> You can use a manual battery switch and operate it remotely
> via a bowden cable (like the choke control on older cars).
> Crash safety is dependent upon limiting the energy that can
> be taken from battery powered wires when the metal is getting
> crunched. The FAA calls for 5a as a limiting value (breaker
> is okay with them, a fuse is MUCH better). A long wire with
> an ANL limiter in it falls WAAAYYYYY out side spirit and
> intent of either (1) positive disconnect of wire by pilot
> using battery contactor and/or relays local to the battery
> bus or limiting the protection of long, always-hot wires
> to 5A or less.
>
> Bob . . .
>
>
Message 21
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| Subject: | Single or Dual batteries?? |
--> AeroElectric-List message posted by: "Carl Morgan - ZK-VII" <zk-vii@blueyonder.co.uk>
Hi,
I'm in the early stages of planning for the electrics systems for a 7A. All
electric is the plan based on Bob's bible. I'm looking for pointers for the
one / two batteries decision.
Current setup will include dual alternators, main and EBUS + main battery.
We are also hoping to go FADEC and electric EFIS. If I put a second battery
in, would dedicating it to the FADEC be a good option, or would providing
EBUS supply make more sense with FADEC off that?
Thanks,
Carl
--
ZK-VII - RV 7A QB
http://www.rvproject.pwp.blueyonder.co.uk/
Cromwell, New Zealand
Message 22
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--> AeroElectric-List message posted by: "James E. Clark" <james@nextupventures.com>
Comments below ...
James
[SNIP]
> >
> >Instructions with new ACK says to change them with each Annual
> Inspection. It
> >also gives the specific "D" cell to be used.
>
> That stops any arguments right dead in their tracks . . . no?
>
> Bob . . .
>
And this is consistent with knowing that you have "fresh" ones in there. You
do not lose anything as the ones that come out should/could go into your
flashlight and serve til their "death". That's what we are doing.
No questions about battery life. No questions about legality. No throwing
away of "unused" batteries.
James
Message 23
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| Subject: | XCOM, Pilot, Lightspeed and customer service. |
--> AeroElectric-List message posted by: "Rob W M Shipley" <rob@robsglass.com>
Tom Friedland, California, Europa, wrote :-
Hi Rob and anyone else interested in XCom products.. BEWARE!
I bought an intercom from them and also had them make up a wiring
harness to connect the intercom and switch between two Microair 760s.
The intercom appears to be good, clear, light and small. HOWEVER,
harness they supplied is totally inadequate. First of all, many the
cables were mislabeled which of course meant they were connected
incorrectly by me. I emailed Michael Coates, their honcho, and was told
he would get right back to me. Did he, NO. I then asked him if I could
return the harness to him or at least could he send me a wiring diagram.
NO RESPONSE. I have attempted to contact him many times and asked at
least if he would send back the $$ I had paid for the harness. NO
RESPONSE.
Since then, Microair has sent me a proper wiring diagram and I find that
XCom did it entirely wrong, used the wrong kind of switch, etc.
BEWARE...
This customer feedback is very useful. I have recently suffered at the hands of
Pilot. Their ear seals on my PA17-76 ANR headset had deteriorated markedly
and I emailed them for help since it was within the five year warranty. Unlike
the glowing reports of superior customer service from Lightspeed owners I was
sorely disappointed.
Pilot emailed me saying that everyone knows that ear seals are only good for about
twelve months and that if I want a permanent solution I must send $25 for
the silicone type. I replied that I felt ear seals on a product with a five year
warranty should actually last five years or more. This failed to impress
them and I was sent the old type as a replacement - the ones that "everyone knows
only last a year". Their words! I suppose they are waiting for my check
for $25 sometime next March or April!
As Tom Friedland said about XCOM if you are considering a Pilot product, BEWARE!
Rob
Rob W M Shipley
N919RV (res) Fuselage .....still!
Message 24
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| Subject: | XCOM, Pilot, Lightspeed and customer service. |
--> AeroElectric-List message posted by: "John Slade" <sladerj@bellsouth.net>
> As Tom Friedland said about XCOM if you are considering a Pilot
> product, BEWARE!
Interesting. I've heard exactly the opposite about Pilot. A friend had a
problem with one of their DNC headsets and sent it back. They refurbished it
for free, including replacing the ear seals. My Pilot unit has performed
flawlessly for 4 years, so I've had no reason to test their support.
Just another data point.
John Slade
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