Today's Message Index:
----------------------
1. 12:13 AM - Aircraft receivers (James Foerster)
2. 12:34 AM - Re: Aircraft receivers (Mickey Coggins)
3. 03:44 AM - Re: Shielded magneto wires - Z Figures (Walter Tondu)
4. 04:14 AM - Re: Aircraft receivers (Harley)
5. 04:29 AM - Re: Shielded magneto wires - Z Figures (Werner Schneider)
6. 04:49 AM - Re: Transformer (Brian Lloyd)
7. 05:18 AM - Re: Transformer (Gerry Holland)
8. 06:48 AM - Shielded magneto wires - Z Figures (PeterHunt1@aol.com)
9. 07:09 AM - Re: Shielded magneto wires - Z Figures (f1rocket@comcast.net)
10. 07:15 AM - Re: Cleveland Crimp Tool Mystery Solved . . . (DAVID REEL)
11. 08:45 AM - Re: Z-13 - latest version of 'simplification' (Phil Birkelbach)
12. 09:50 AM - Re: Z-13 - latest version of 'simplification' (David Carter)
13. 12:27 PM - Re: Z-13 - latest version of 'simplification' (Brian Lloyd)
14. 12:27 PM - Re: Z-13 - latest version of 'simplification' (Brian Lloyd)
15. 12:51 PM - Electrical current load spreadsheet (David Carter)
16. 12:59 PM - Re: Z-13 - latest version of 'simplification' (David Carter)
17. 01:07 PM - Re: Z-13 - latest version of 'simplification' (Ken)
18. 01:26 PM - Re: Z-13 - latest version of 'simplification' (Phil Birkelbach)
19. 02:17 PM - Re: Z-13 - latest version of 'simplification' (David Carter)
20. 02:17 PM - Re: Z-13 - latest version of 'simplification' (Brian Lloyd)
21. 02:22 PM - Wire size calculator help (David Carter)
22. 02:31 PM - (Tracy)
23. 03:02 PM - Re: Cleveland Crimp Tool Mystery Solved . . (Robert L. Nuckolls, III)
24. 03:14 PM - Re: Z-13 - latest version of 'simplification' (Matt Prather)
25. 04:30 PM - Re: 0.70 RCVD_BY_IP Received by mail server with no name 1.16 MISSING_SUBJECT Missing Subject: header (Chris Krieg)
26. 08:04 PM - Re: Z-13 - latest version of (Robert L. Nuckolls, III)
Message 1
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| Subject: | Aircraft receivers |
--> AeroElectric-List message posted by: "James Foerster" <jmfpublic@comcast.net>
Does anyone have any experience with the XCOM 760, available from
Aircraft Spruce? It is made by Micheal Coates out of Australia, and
seems to be loosely based on the Micro Air 760. It seems to have
advantages, in that it has a VOX circuit rather than 'hot mike' that
Micro Air uses. It is priced just under $1000 now, as is the iCom
ic-A200. The iCom looks nice, but I recall at least one negative
comment about ignition noise--which may be very antenna and plane
specific. Any comments?
The web page comparing the XCOM to others is
http://www.mcp.com.au/xcom760/comparison/comparison.html
Message 2
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| Subject: | Re: Aircraft receivers |
--> AeroElectric-List message posted by: Mickey Coggins <mick-matronics@rv8.ch>
Hi,
I have read at least one positive PIREP on the "RVs_in_Aus"
yahoo group.
Mickey
>Does anyone have any experience with the XCOM 760, available from
>Aircraft Spruce? It is made by Micheal Coates out of Australia, and
>seems to be loosely based on the Micro Air 760. It seems to have
>advantages, in that it has a VOX circuit rather than 'hot mike' that
>Micro Air uses. It is priced just under $1000 now, as is the iCom
>ic-A200. The iCom looks nice, but I recall at least one negative
>comment about ignition noise--which may be very antenna and plane
>specific. Any comments?
--
Mickey Coggins
http://www.rv8.ch/
#82007 QB Wings/Fuselage
Message 3
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| Subject: | Re: Shielded magneto wires - Z Figures |
--> AeroElectric-List message posted by: Walter Tondu <walter@tondu.com>
On 09/02 6:49, Werner Schneider wrote:
> --> AeroElectric-List message posted by: "Werner Schneider" <wernerschneider@compuserve.com>
>
> > > > aha! excellent data point. This almost always points to
> > > > a ground loop. You have more than one ground for avionics/audio
> > > > equipment that's reading high current ground returns for high
> > > > current equipment like landing lights, pitot heat, etc.
> > > >
> > > Hello Bob,
> > >
> > > interesting, I followed the recommendation and grounded each and every
> > > equipment to the single 48-tab ground block from B&C, but my panel is
> metal
> > > and the avionics rack are directly screwed onto the aluminum as well as
> the
> > > whole panel is hinged on the metal cage, I added a separate ground from
> the
> > > tab block to the panel but no change. The Battery is connected with a
> 2AWG
> > > cable to the ground tab, on the other side of the firewall a braided
> cable
> > > is going to the engine crankcase.
> > >
> > > As told the noise is very low and maybe only audible to me because of
> the
> > > ANR headset.
> > >
> >
> > Are both Mags grounded to the ground block as well?
>
> Hello Walter,
>
> as I'm using a Lasar Ignition the game is a tad different, the Ignition Box
> is grounded to the block as well as the magneto wires coming from the box
> via the magneto/starter switch.
I have the LASAR ignition as well and each magneto has a grounding
strap. Doesn't yours?
--
Walter Tondu
http://www.rv7-a.com
Message 4
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| Subject: | Re: Aircraft receivers |
--> AeroElectric-List message posted by: Harley <harley@agelesswings.com>
I had considered that model...but just received my Microair M760 yesterday!
The Xcom does look like it has some better features, but I was as much
concerned with price...and Microair had the best deal (IMHO) with their
combo package that included everything including the transponder,
transceiver, VOX intercom, encoder and cables and antenna for $2700 US.
That's a considerable discount from Micrtoir's individual prices, with
an additional 5% from OxAero in Mississippi where I bought it.
http://www.oxaero.com/Microair-ComboKits.asp
And with the fine reputation that Microair has acheived in the field, I
didn't want to take a chance with the new kid on the block...it may be
better, but I didn't want to be the one to find out that it isn't.
Harley Dixon
www.agelesswings.com
James Foerster wrote:
>--> AeroElectric-List message posted by: "James Foerster" <jmfpublic@comcast.net>
>
>Does anyone have any experience with the XCOM 760, available from
>Aircraft Spruce? It is made by Micheal Coates out of Australia, and
>seems to be loosely based on the Micro Air 760. It seems to have
>advantages, in that it has a VOX circuit rather than 'hot mike' that
>Micro Air uses. It is priced just under $1000 now, as is the iCom
>ic-A200. The iCom looks nice, but I recall at least one negative
>comment about ignition noise--which may be very antenna and plane
>specific. Any comments?
>
>The web page comparing the XCOM to others is
>http://www.mcp.com.au/xcom760/comparison/comparison.html
>
>
>
>
Message 5
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| Subject: | Re: Shielded magneto wires - Z Figures |
--> AeroElectric-List message posted by: "Werner Schneider" <wernerschneider@compuserve.com>
> > Hello Walter,
> >
> > as I'm using a Lasar Ignition the game is a tad different, the Ignition
Box
> > is grounded to the block as well as the magneto wires coming from the
box
> > via the magneto/starter switch.
>
> I have the LASAR ignition as well and each magneto has a grounding
> strap. Doesn't yours?
>
Hello Walter,
yes, every magneto has a bonding strap to the crankcase housing.
Werner
Message 6
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--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
On Sep 2, 2004, at 1:15 AM, N1deltawhiskey@aol.com wrote:
> --> AeroElectric-List message posted by: N1deltawhiskey@aol.com
>
>
>> ... a simple pad ...
>
> For the benefit of the clueless (me), what are we talking about here?
The signal as it comes from the car stereo is much too high for the
music input of the audio panel so it must be reduced. A 'pad' is a
combination of resistors that reduces the signal by a set amount while
still maintaining the proper resistances that the two devices expect to
see. The output of the car stereo is probably on the order of 24V
peak-to-peak at full output and the maximum input to the audio panel is
probably on the order of 2V peak-to-peak. Something needs to cut the
signal voltage down by a factor of 10 or so (20dB).
But there is a second problem that renders the pad undesirable in this
application and makes the transformer more desirable. The speaker
outputs of most car stereos are balanced (bridged actually). The
outputs at the speaker leads are equal and opposite in phase so you
don't have one lead at ground. Both leads are above ground but
opposite in polarity, i.e. when the signal on one speaker lead is
momentarily at +10V the other lead is at -10V leaving you with 20V
between the two leads. There is no ground reference. They do this
because you can get four times the power, approximately 20W, from a 12V
supply when you do this.
Unlike the pad, the transformer works regardless of the ground
reference. Both sides of the transformer may have different ground
references and still work just fine. Since there is no common ground
to both sides the transformer may also be used to break a ground-loop.
In this application the original poster (sorry, I forget who posted the
original question) had purchased 500 ohm to 8 ohm coupling transformers
from Radio Shack. The problem here is, if they hook the 8 ohm side to
the car stereo the output voltage at the 500 ohm side will be *way* too
high. The trick is to connect the transformer "backwards", i.e.
connect the 500 ohm side to the car stereo speaker leads and the 8 ohm
side to the audio panel music input. Now the transformer becomes a
step-down transformer.
The voltage ratio of the transformer is the ratio of the square roots
of the impedances or about 8:1 in the case of a 500 ohm to 8 ohm
transformer [ sqrt(500)/sqrt(8) ]. That is about the right ratio of
signal output at the speaker lead of the car stereo to signal input to
the audio panel. The amplifiers in car stereos are basically power
op-amps and are stable without a load so you don't need to put an 8-ohm
load on the amplifier to make it work properly.
As Bob suggested, the transformers are quite simple and solve the
problem nicely. This solution will probably horrify any tweak
audiophile worth his or her salt but given the low-fidelity nature of
most aviation headphones and the low-fidelity nature of automobile
audio electronics, the quality of the transformers is probably not
really an issue.
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 7
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--> AeroElectric-List message posted by: Gerry Holland <gnholland@onetel.com>
Brian Hi!
> For the benefit of the clueless (me), what are we talking about here?
Great explanation on Audio. Many Thanks
Gerry
Europa 384 G-FIZY
Trigear with Rotax 912 and Arplast CS Prop.
Engine very near to starting.
Painting completed. Vinyl design scheme to be added.
Completing Wiring to Panel.
Dynon EFIS, KMD 150, Icom A-200 and SL70 Transponder. AoA Fitted.
Shoulder Width Mod. Heater Unit constructed and fitted.
http://www.g-fizy.com
+44 7808 402404
gnholland@onetel.com
Message 8
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| Subject: | Shielded magneto wires - Z Figures |
--> AeroElectric-List message posted by: PeterHunt1@aol.com
Bob and others:
I still need some help. Concerning my question as to how/if to use shielded
wires on my magneto P leads coming from my LASAR control box, Bob N. responds
"What do the LASAR drawings show? Where there are illustration instructions
for the system, those should be your first source of installation data."
The drawings show the LASAR control box mounted in the engine compartment
with the blue left magneto P lead and green right magneto P lead coming into the
cockpit. A "dot" at the end of each of these lines suggests termination
points which I can only assume is a switch. The drawing does not suggest shielded
wires. Now, on the next page are the written instructions which imply the use
of a conventional (all in one) start switch, not left and right magneto
switches like I have. The instructions read as follows:
"Attach the left P-lead switch wire to the blue wire in the LASAR low
voltage control harness. NOTE: Ensure shielding on P-lead does not ground P-lead
at splice. Attach the right P-lead switch to the green wire in the LASAR low
voltage control harness. NOTE: Ensure shielding on P-lead switch wire does
not ground P-lead at splice."
Now to me that suggests there are shielded wires in use. My question
remains. Do I need shielded wire through the cockpit all the way to the LASAR
control box to the two p-leads out of the box or may I run the two unshielded LASAR
P-lead out to my switches? So I called Unison Industries (makers of LASAR).
After a long discussion their answer was "we don't know." They did point out
that even with my magneto switches open during engine running there is voltage
in the P-leads, just no current flowing. That is when I called for help on
this list.
Thanks again Werner for your response. Wener didn't shield his LASAR wires.
How about the others of you who have LASAR systems???? What did you do?
Yes, Bob, you are always welcome here in Clearwater. Stay with me as before
and do bring Dee with you. My RV-6 may be flying by late spring and if I have
flown my test time off you are welcome to a ride. If not, we can do some
sailing.
Pete Hunt
Clearwater, FL
RV-6 close to finished
Message 9
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| Subject: | Re: Shielded magneto wires - Z Figures |
--> AeroElectric-List message posted by: f1rocket@comcast.net
I did not use shielded wire to connect up my LASAR system in my RV-6. I used the
wire loom provided in the kit and wired directly to my keyed ignition switch.
I did not have any problem with noise in my audio system. The airplane was
wired per Bob's suggestions in the Connection.
Go ahead and wire them up to your separate toggle switches and forget about it.
Randy
F1 Rocket
http://f1rocket.home.comcast.net/
-------------- Original message --------------
> --> AeroElectric-List message posted by: PeterHunt1@aol.com
>
> Bob and others:
>
> I still need some help. Concerning my question as to how/if to use shielded
> wires on my magneto P leads coming from my LASAR control box, Bob N. responds
> "What do the LASAR drawings show? Where there are illustration instructions
> for the system, those should be your first source of installation data."
>
> The drawings show the LASAR control box mounted in the engine compartment
> with the blue left magneto P lead and green right magneto P lead coming into
the
> cockpit. A "dot" at the end of each of these lines suggests termination
> points which I can only assume is a switch. The drawing does not suggest
> shielded
> wires. Now, on the next page are the written instructions which imply the use
> of a conventional (all in one) start switch, not left and right magneto
> switches like I have. The instructions read as follows:
>
> "Attach the left P-lead switch wire to the blue wire in the LASAR low
> voltage control harness. NOTE: Ensure shielding on P-lead does not ground
> P-lead
> at splice. Attach the right P-lead switch to the green wire in the LASAR low
> voltage control harness. NOTE: Ensure shielding on P-lead switch wire does
> not ground P-lead at splice."
>
> Now to me that suggests there are shielded wires in use. My question
> remains. Do I need shielded wire through the cockpit all the way to the LASAR
> control box to the two p-leads out of the box or may I run the two unshielded
> LASAR
> P-lead out to my switches? So I called Unison Industries (makers of LASAR).
> After a long discussion their answer was "we don't know." They did point out
> that even with my magneto switches open during engine running there is voltage
> in the P-leads, just no current flowing. That is when I called for help on
> this list.
>
> Thanks again Werner for your response. Wener didn't shield his LASAR wires.
> How about the others of you who have LASAR systems???? What did you do?
>
> Yes, Bob, you are always welcome here in Clearwater. Stay with me as before
> and do bring Dee with you. My RV-6 may be flying by late spring and if I have
> flown my test time off you are welcome to a ride. If not, we can do some
> sailing.
>
> Pete Hunt
> Clearwater, FL
> RV-6 close to finished
>
>
>
>
>
>
I did not use shielded wire to connect up my LASAR system in my RV-6. I used the
wire loom provided in the kit and wired directly to my keyed ignition switch.
I did not have any problem with noise in my audio system. The airplane was wired
per Bob's suggestions in the Connection.
Go ahead and wire them up to your separate toggle switches and forget about it.
Randy
F1 Rocket
http://f1rocket.home.comcast.net/
-------------- Original message --------------
-- AeroElectric-List message posted by: PeterHunt1@aol.com
Bob and others:
I still need some help. Concerning my question as to how/if to use shielded
wires on my magneto P leads coming from my LASAR control box, Bob N. responds
"What do the LASAR drawings show? Where there are illustration instructions
for the system, those should be your first source of installation data."
The drawings show the LASAR control box mounted in the engine compartment
with the blue left magneto P lead and green right magneto P lead coming into the
cockpit. A "dot" at the end of each of these lines suggests termination
points which I can only assume is a switch. The drawing does not suggest
shielded
wires. Now, on the next p
age are the written instructions which imply the use
of a conventional (all in one) start switch, not left and right magneto
switches like I have. The instructions read as follows:
"Attach the left P-lead switch wire to the blue wire in the LASAR low
voltage control harness. NOTE: Ensure shielding on P-lead does not ground
P-lead
at splice. Attach the right P-lead switch to the green wire in the LASAR low
voltage control harness. NOTE: Ensure shielding on P-lead switch wire does
not ground P-lead at splice."
Now to me that suggests there are shielded wires in use. My question
remains. Do I need shielded wire through the cockpit all the way to the LASAR
control box to the two p-leads out of the box or may I run the two unshielded
LASAR
P-lead out to my switches? So I called Unison Industries (makers of LASAR).
After a long discussion
their answer was "we don't know." They did point out
that even with my magneto switches open during engine running there is voltage
in the P-leads, just no current flowing. That is when I called for help on
this list.
Thanks again Werner for your response. Wener didn't shield his LASAR wires.
How about the others of you who have LASAR systems???? What did you do?
Yes, Bob, you are always welcome here in Clearwater. Stay with me as before
and do bring Dee with you. My RV-6 may be flying by late spring and if I have
flown my test time off you are welcome to a ride. If not, we can do some
sailing.
Pete Hunt
Clearwater, FL
RV-6 close to finished
gh the Contributions
_
-= Photo Share: http://www.matronics.com/photoshare
Message 10
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| Subject: | Re: Cleveland Crimp Tool Mystery Solved . . . |
--> AeroElectric-List message posted by: "DAVID REEL" <dreel@cox.net>
Mystery not solved! I certainly did not put the terminals in the tool backwards.
Buzz returned the terminal with the bad crimp that I sent him & I'm sending
it to you. You will note that the deep crimp is where it should be on the terminal
side of the barrel. I'm also sending a crimp Buzz sent me along with
a replacement tool. I figure he thought the problem was having a bad example
of the tool. Just feeling the two crimps shows how much deeper the indentations
in Buzz's good crimp are compared to mine. Now if you got a good crimp using
my tool, that leaves only the terminal as suspect. I look forward to hearing
what you think when you get the terminal. Buzz's crimp also captures the tefzel
much better than mine.
Dave Reel - RV8A
Message 11
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: Phil Birkelbach <phil@petrasoft.net>
The thing that jumps out at me on your modification is that you have
created a single point of failure for your endurance buss with the
switch. A better solution would be two switches. One for the main feed
and the other for the battery buss feed. Actually a better solution
would be the diode. I agree that diodes do fail, but in my experience
switches fail more often than diodes. I would be curious what your
experience with diodes is that causes you to believe that a switch is
more reliable.
Another problem with the single switch is that you will have a
millisecond or two where there is no voltage. I imagine that this
probably won't cause any grief.
There is also an unprotected wire between the main buss and your e-buss
switch. This wire is unprotected in the original architecture as well
but it is assumed that the diode is physically close to both busses.
You will most likely mount that switch on the panel, which will make the
wire longer than 6" and therefore it will need to be protected. If you
replace the single switch with two switches you will also have to
protect both wires from both ends of both switches because they will all
be too long and will have the potential to be powered from both ends.
It seems to me the parts count is increasing at an alarming rate and
this decreases reliablity in any system.
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Panel
http://www.myrv7.com
David Carter wrote:
>--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
>
>I've learned some more about Autocad (Intellicad actually) and figured out
>how to use the symbol "blocks", etc.
> - Wasn't able to eliminate the "alternator switch" and only use the CB.
>Reason: The OVM's relay coils are hooked up to the batt bus so it would
>suck the battery dry unless there's a switch to disconnect the coil after
>engine shutdown/overnight, etc. I don't want to use the CB after every
>shutdown - rather "use a switch for a switch - not a CB".
>
>I printed my dwg file as pdf and re-posted to my website. Hope to get some
>feedback form 'Lectric Bob and others.
> - Especially what I did to the Endurance Bus circuit. I don't like
>diodes - they fail, even though they are said to be "solid state, highly
>reliable". My experience is otherwise. Rather use a simple switch to
>select how the E-bus gets fed when the electrons hit the fan.
>
>http://www.datarecall.net/~dcarter/Builder's%20Log.html
>
>David
>
>
>
>
Message 12
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Phil,
Good & helpful observations.
OK, perhaps someone can help me "increase my confidence in diodes". Before
that, I figure the switch in my current Z-13 will only be used once or twice
in my lifetime and its lifetime. So I don't think "reliability of switches"
is even an issue. I'm surely not worried about it "shorting" across any of
its terminals in normal use (unactuated, just a static failure).
But parts count is a good issue. So, what "range of options" do I have on
the diode, installed as per original Z-13? I know that resistors have
"watts" ratings. How about diodes? What would be a good diode to use?
Would like to see its specs on a supplier's web site or some such.
David
----- Original Message -----
From: "Phil Birkelbach" <phil@petrasoft.net>
Subject: Re: AeroElectric-List: Z-13 - latest version of 'simplification'
> --> AeroElectric-List message posted by: Phil Birkelbach
<phil@petrasoft.net>
>
> The thing that jumps out at me on your modification is that you have
> created a single point of failure for your endurance buss with the
> switch. A better solution would be two switches. One for the main feed
> and the other for the battery buss feed. Actually a better solution
> would be the diode. I agree that diodes do fail, but in my experience
> switches fail more often than diodes. I would be curious what your
> experience with diodes is that causes you to believe that a switch is
> more reliable.
>
> Another problem with the single switch is that you will have a
> millisecond or two where there is no voltage. I imagine that this
> probably won't cause any grief.
>
> There is also an unprotected wire between the main buss and your e-buss
> switch. This wire is unprotected in the original architecture as well
> but it is assumed that the diode is physically close to both busses.
> You will most likely mount that switch on the panel, which will make the
> wire longer than 6" and therefore it will need to be protected. If you
> replace the single switch with two switches you will also have to
> protect both wires from both ends of both switches because they will all
> be too long and will have the potential to be powered from both ends.
> It seems to me the parts count is increasing at an alarming rate and
> this decreases reliablity in any system.
>
> Godspeed,
>
> Phil Birkelbach - Houston Texas
> RV-7 N727WB (Reserved) - Panel
> http://www.myrv7.com
>
>
Message 13
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
On Sep 2, 2004, at 12:19 PM, David Carter wrote:
> OK, perhaps someone can help me "increase my confidence in diodes".
> Before
> that, I figure the switch in my current Z-13 will only be used once or
> twice
> in my lifetime and its lifetime. So I don't think "reliability of
> switches"
> is even an issue. I'm surely not worried about it "shorting" across
> any of
> its terminals in normal use (unactuated, just a static failure).
Switches need to switch on a regular basis to keep the contacts clean
and reliable. A switch that sits in one position is asking for a
failure.
A diode has no moving parts and no place for potential oxidation (if
installed properly). It will just last a lot longer.
> I know that resistors have "watts" ratings. How about diodes?
They have a watts rating too but because their voltage drop is
relatively constant they are rated in amps. Schottky type diodes have
a lower forward voltage drop so they can handle more current in the
same package before dissipating the same amount or power.
> What would be a good diode to use?
I prefer Schottky power rectifier diodes. Bob likes the old
tried-n-true silicon rectifiers. I prefer the 0.3V drop to the 0.7+V
drop of the plain silicon rectifier. You pays yer money and you takes
yer choice.
> Would like to see its specs on a supplier's web site or some such.
It depends on your load in amps. How much is your e-buss going to draw
when it is fully loaded?
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 14
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
On Sep 2, 2004, at 12:19 PM, David Carter wrote:
> OK, perhaps someone can help me "increase my confidence in diodes".
> Before
> that, I figure the switch in my current Z-13 will only be used once or
> twice
> in my lifetime and its lifetime. So I don't think "reliability of
> switches"
> is even an issue. I'm surely not worried about it "shorting" across
> any of
> its terminals in normal use (unactuated, just a static failure).
Switches need to switch on a regular basis to keep the contacts clean
and reliable. A switch that sits in one position is asking for a
failure.
A diode has no moving parts and no place for potential oxidation (if
installed properly). It will just last a lot longer.
> I know that resistors have "watts" ratings. How about diodes?
They have a watts rating too but because their voltage drop is
relatively constant they are rated in amps. Schottky type diodes have
a lower forward voltage drop so they can handle more current in the
same package before dissipating the same amount or power.
> What would be a good diode to use?
I prefer Schottky power rectifier diodes. Bob likes the old
tried-n-true silicon rectifiers. I prefer the 0.3V drop to the 0.7+V
drop of the plain silicon rectifier. You pays yer money and you takes
yer choice.
> Would like to see its specs on a supplier's web site or some such.
It depends on your load in amps. How much is your e-buss going to draw
when it is fully loaded?
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 15
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| Subject: | Electrical current load spreadsheet |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Mike,
I'm replying both to the list (no attachments) and to you (so I can attach a
sophisticated spreadsheet Shannon Knoepfliein posted a year or so ago).
I'll also attach my mod of that spreadsheet showing my lower budget loads,
as far as I know it right now, and arranged a little different, with some
sub-totals and "accumulated sub-totals" after "Batt Bus", "Enduance Bus",
"Main Bus"; also some additional columns for "additional phases of flight".
Stuff I don't plan to use was cut and moved down below that, so it is still
there for reference.
Also attached Richard Reynold's BusLoad.xls - another perspective and "data
point"
David
Message 16
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Thanks, Brian - good words. 'Lectric Bob likes to use a certain "Bridge
Rectifier"? (bridge something) that is in a good package for mounting and
you don't have to use all the leads and parts inside. I think the guts are
probably just plain silicon diodes, though - not Schottky.
Do not archive.
David
----- Original Message -----
From: "Brian Lloyd" <brianl@lloyd.com>
Subject: Re: AeroElectric-List: Z-13 - latest version of 'simplification'
> --> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
>
> On Sep 2, 2004, at 12:19 PM, David Carter wrote:
>
> > OK, perhaps someone can help me "increase my confidence in diodes".
> > Before
> > that, I figure the switch in my current Z-13 will only be used once or
> > twice
> > in my lifetime and its lifetime. So I don't think "reliability of
> > switches"
> > is even an issue. I'm surely not worried about it "shorting" across
> > any of
> > its terminals in normal use (unactuated, just a static failure).
>
> Switches need to switch on a regular basis to keep the contacts clean
> and reliable. A switch that sits in one position is asking for a
> failure.
>
> A diode has no moving parts and no place for potential oxidation (if
> installed properly). It will just last a lot longer.
>
> > I know that resistors have "watts" ratings. How about diodes?
>
> They have a watts rating too but because their voltage drop is
> relatively constant they are rated in amps. Schottky type diodes have
> a lower forward voltage drop so they can handle more current in the
> same package before dissipating the same amount or power.
>
> > What would be a good diode to use?
>
> I prefer Schottky power rectifier diodes. Bob likes the old
> tried-n-true silicon rectifiers. I prefer the 0.3V drop to the 0.7+V
> drop of the plain silicon rectifier. You pays yer money and you takes
> yer choice.
>
> > Would like to see its specs on a supplier's web site or some such.
>
> It depends on your load in amps. How much is your e-buss going to draw
> when it is fully loaded?
>
> Brian Lloyd 6501 Red Hook Plaza
> brianl@lloyd.com Suite 201
> +1.340.998.9447 St. Thomas, VI 00802
Message 17
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| Subject: | Re: Z-13 - latest version of 'simplification' |
on juliet
--> AeroElectric-List message posted by: Ken <klehman@albedo.net>
Well David, seeing as how you are talking about switches, that last
diagram also shows your 40 amp alternator current going through a
switch. Most of the switches that I see can't really handle that
especially with push on connectors. Just because you are not planning to
move the switch when loads are high does not mean that internal (or
external) connections won't heat up and fail in service. In the original
Z-13 all the high currents are switched by the relay and as I mentioned
before, I ended up using a hefty battery contactor for that with a 40
amp alternator. I prefer the original AEC Z-13 architecture. There is
lots of diode discussion in the archives.
Ken
David Carter wrote:
>--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
>
>Phil,
>
>Good & helpful observations.
>
>OK, perhaps someone can help me "increase my confidence in diodes". Before
>that, I figure the switch in my current Z-13 will only be used once or twice
>in my lifetime and its lifetime. So I don't think "reliability of switches"
>is even an issue. I'm surely not worried about it "shorting" across any of
>its terminals in normal use (unactuated, just a static failure).
>
>But parts count is a good issue. So, what "range of options" do I have on
>the diode, installed as per original Z-13? I know that resistors have
>"watts" ratings. How about diodes? What would be a good diode to use?
>Would like to see its specs on a supplier's web site or some such.
>
>David
>
>----- Original Message -----
>From: "Phil Birkelbach" <phil@petrasoft.net>
>To: <aeroelectric-list@matronics.com>
>Subject: Re: AeroElectric-List: Z-13 - latest version of 'simplification'
>
>
>
>
>>--> AeroElectric-List message posted by: Phil Birkelbach
>>
>>
><phil@petrasoft.net>
>
>
>>The thing that jumps out at me on your modification is that you have
>>created a single point of failure for your endurance buss with the
>>switch. A better solution would be two switches. One for the main feed
>>and the other for the battery buss feed. Actually a better solution
>>would be the diode. I agree that diodes do fail, but in my experience
>>switches fail more often than diodes. I would be curious what your
>>experience with diodes is that causes you to believe that a switch is
>>more reliable.
>>
>>Another problem with the single switch is that you will have a
>>millisecond or two where there is no voltage. I imagine that this
>>probably won't cause any grief.
>>
>>There is also an unprotected wire between the main buss and your e-buss
>>switch. This wire is unprotected in the original architecture as well
>>but it is assumed that the diode is physically close to both busses.
>>You will most likely mount that switch on the panel, which will make the
>>wire longer than 6" and therefore it will need to be protected. If you
>>replace the single switch with two switches you will also have to
>>protect both wires from both ends of both switches because they will all
>>be too long and will have the potential to be powered from both ends.
>>It seems to me the parts count is increasing at an alarming rate and
>>this decreases reliablity in any system.
>>
>>Godspeed,
>>
>>Phil Birkelbach - Houston Texas
>>RV-7 N727WB (Reserved) - Panel
>>http://www.myrv7.com
>>
>>
Message 18
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: Phil Birkelbach <phil@petrasoft.net>
I hope you plan to use that switch every time you start the airplane.
You always check your backups during pre-flight. Besides whether or not
you use it still doesn't change the fact it is still a single point of
failure and I would contend that not using the switch will actually hurt
it's reliablity, due to corrosion and other factors. It is a mechanical
device after all. And it's not just the switch that is the single point
of failure it is also two terminals and a piece of wire any one of which
will cause your endurance buss to go cold.
Diodes are generally rated in Amps. The diode that is sold by B & C
Specialty (and that Bob recomends) is actually a full wave rectifier. I
think that it is rated at 25Amps or so. The reasoning for the FWR is
simply that it is easy to physically mount and since it has 1/4" fast on
tabs it is easy to wire to. It will also dissipate it's heat well since
it's heat sink will most likely be bolted to some metal on most planes.
If you are worried then a proper heat sink for the package can be had at
Radio Shack for a couple of bucks.
The only time I have ever seen diodes fail is when they were subjected
to too much heat (or allowed to generate too much heat of their own).
Most alternator diodes fail this way. That is why I asked you about
your experience with diodes. I suspect that your bad luck with diodes
had to do with too much heat, probably in alternators. They do need to
dissipate some energy but the one that we are discussing will be as
happy as it can be for years running well below it's maximum current
rating and properly heat sunk. Also we are only dumping the heat from
one of the four diodes in the package. You can estimate the power that
you'll need to dissipate by multiplying the current through the device
by 0.7, which is the forward voltage drop of the typical silicon diode.
At 10 amps you're looking at around 7 watts. That'll barely get warm.
Here is a Mouser link...
http://checkoway.com/url/?s=49833a03
Now where are all those Schottky diode guys??? :-)
Godspeed,
Phil Birkelbach - Houston Texas
RV-7 N727WB (Reserved) - Panel
http://www.myrv7.com
David Carter wrote:
>--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
>
>Phil,
>
>Good & helpful observations.
>
>OK, perhaps someone can help me "increase my confidence in diodes". Before
>that, I figure the switch in my current Z-13 will only be used once or twice
>in my lifetime and its lifetime. So I don't think "reliability of switches"
>is even an issue. I'm surely not worried about it "shorting" across any of
>its terminals in normal use (unactuated, just a static failure).
>
>But parts count is a good issue. So, what "range of options" do I have on
>the diode, installed as per original Z-13? I know that resistors have
>"watts" ratings. How about diodes? What would be a good diode to use?
>Would like to see its specs on a supplier's web site or some such.
>
>David
>
>----- Original Message -----
>From: "Phil Birkelbach" <phil@petrasoft.net>
>To: <aeroelectric-list@matronics.com>
>Subject: Re: AeroElectric-List: Z-13 - latest version of 'simplification'
>
>
>
>
>>--> AeroElectric-List message posted by: Phil Birkelbach
>>
>>
><phil@petrasoft.net>
>
>
>>The thing that jumps out at me on your modification is that you have
>>created a single point of failure for your endurance buss with the
>>switch. A better solution would be two switches. One for the main feed
>>and the other for the battery buss feed. Actually a better solution
>>would be the diode. I agree that diodes do fail, but in my experience
>>switches fail more often than diodes. I would be curious what your
>>experience with diodes is that causes you to believe that a switch is
>>more reliable.
>>
>>Another problem with the single switch is that you will have a
>>millisecond or two where there is no voltage. I imagine that this
>>probably won't cause any grief.
>>
>>There is also an unprotected wire between the main buss and your e-buss
>>switch. This wire is unprotected in the original architecture as well
>>but it is assumed that the diode is physically close to both busses.
>>You will most likely mount that switch on the panel, which will make the
>>wire longer than 6" and therefore it will need to be protected. If you
>>replace the single switch with two switches you will also have to
>>protect both wires from both ends of both switches because they will all
>>be too long and will have the potential to be powered from both ends.
>>It seems to me the parts count is increasing at an alarming rate and
>>this decreases reliablity in any system.
>>
>>Godspeed,
>>
>>Phil Birkelbach - Houston Texas
>>RV-7 N727WB (Reserved) - Panel
>>http://www.myrv7.com
>>
>>
>>
>>
>
>
>
>
Message 19
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Ken & Phil,
How I love this list. A guy can "try out his budding knowledge" and get
good technical "educational feedback". Thanks for taking the time to
explain this stuff beyond my fledgling knowledge.
About the alternator switch - that was a late at night, hastily added item -
zero thought about anything except running down my battery without a switch
there. I'll add (re-insert) a standard contactor (as in original Z-13!! or
lower holding current EV200 by Kilovac mentioned by James Foerster - if
price can be "refined") or solid state device that can handle the current
(Eric Jones's)
About the E-bus switch instead of a diode - Yep, my experience is automotive
alternator diodes. Plus one that shorted on a ckt board in an A-7 "Big
Eight" test station ($1 million for each of the 8 test stations) - cost
about $100,000 in parts after the unprotected failure cascaded throughout
the test station and took out about all of its electrical guts.
- The point about heat affecting the auto alternator diodes - vs very
benign environment for the E-bus diode - is well taken. I'll go with the
diode (and maybe put a "knife blade" switch in parallel in case the diode
shorts or opens - no, just kidding).
Thanks again for the help
David
----- Original Message -----
From: "Ken" <klehman@albedo.net>
Subject: Re: AeroElectric-List: Z-13 - latest version of 'simplification' on
juliet
> --> AeroElectric-List message posted by: Ken <klehman@albedo.net>
>
> Well David, seeing as how you are talking about switches, that last
> diagram also shows your 40 amp alternator current going through a
> switch. Most of the switches that I see can't really handle that
> especially with push on connectors. Just because you are not planning to
> move the switch when loads are high does not mean that internal (or
> external) connections won't heat up and fail in service. In the original
> Z-13 all the high currents are switched by the relay and as I mentioned
> before, I ended up using a hefty battery contactor for that with a 40
> amp alternator. I prefer the original AEC Z-13 architecture. There is
> lots of diode discussion in the archives.
> Ken
>
Message 20
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: Brian Lloyd <brianl@lloyd.com>
On Sep 2, 2004, at 3:58 PM, David Carter wrote:
> --> AeroElectric-List message posted by: "David Carter"
> <dcarter@datarecall.net>
>
> Thanks, Brian - good words. 'Lectric Bob likes to use a certain
> "Bridge
> Rectifier"? (bridge something) that is in a good package for mounting
> and
> you don't have to use all the leads and parts inside. I think the
> guts are
> probably just plain silicon diodes, though - not Schottky.
That is 100% correct. I prefer to use the schottky diodes in the
TO-220 package. They are more difficult to mount but then, if that is
too difficult you probably shouldn't be building an airplane anyway.
;-)
Brian Lloyd 6501 Red Hook Plaza
brianl@lloyd.com Suite 201
+1.340.998.9447 St. Thomas, VI 00802
Message 21
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| Subject: | Wire size calculator help |
--> AeroElectric-List message posted by: "David Carter" <dcarter@datarecall.net>
Mike, here's two spreadsheets (attached to the e-mail to your address, won't
be on the Aeroel List).
- The one with color "wiresize.xls" is sophisticated from someone else.
I think I added the right columns to figure voltage drop - because I believe
Bob suggested in the Aeroelectric Conn to use bigger wires for longer runs
so as to not drop more than 5% of voltage - it isn't even an issue of
heating the wire. I added that to the traditional "don't fry the wire"
calcs.
- The other, "David's wire size...", is a simple sample that I did on my
own - it illustrates the voltage drop thing - I added 3 lines for your 7amp
load with different lengths of 22 awg and a line for 18 awg (didn't know
what length you were looking at so just picked something like back in the
tail or to a wingtip).
David
Message 22
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0.70 RCVD_BY_IP Received by mail server with no name
1.16 MISSING_SUBJECT Missing Subject: header
--> AeroElectric-List message posted by: Tracy <tracyinva@gmail.com>
please take me off this list!!
Message 23
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|
| Subject: | Re: Cleveland Crimp Tool Mystery Solved . . |
.
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
.
At 10:17 AM 9/2/2004 -0400, you wrote:
>--> AeroElectric-List message posted by: "DAVID REEL" <dreel@cox.net>
>
>Mystery not solved! I certainly did not put the terminals in the tool
>backwards. Buzz returned the terminal with the bad crimp that I sent him
>& I'm sending it to you. You will note that the deep crimp is where it
>should be on the terminal side of the barrel. I'm also sending a crimp
>Buzz sent me along with a replacement tool. I figure he thought the
>problem was having a bad example of the tool. Just feeling the two crimps
>shows how much deeper the indentations in Buzz's good crimp are compared
>to mine. Now if you got a good crimp using my tool, that leaves only the
>terminal as suspect. I look forward to hearing what you think when you
>get the terminal. Buzz's crimp also captures the tefzel much better than mine.
Without a doubt, there may be terminals that will work with
this tool. I used AMP PIDG terminals and got a good wire grip
but poor insulation grip on tefzel. So we had half-of-a-good
crimp. I didn't try a Plasti-Grip terminal . . . I'm not sure
I have any around here. These have a bit more massive insulators
and may well close down on the wire a bit better.
Bob . . .
---
Message 24
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| Subject: | Re: Z-13 - latest version of 'simplification' |
--> AeroElectric-List message posted by: "Matt Prather" <mprather@spro.net>
Hi David,
> --> AeroElectric-List message posted by: "David Carter"
> <dcarter@datarecall.net>
>
> Ken & Phil,
>
> How I love this list. A guy can "try out his budding knowledge" and get
> good technical "educational feedback". Thanks for taking the time to
> explain this stuff beyond my fledgling knowledge.
This list is a fantastic resource. I continue to learn a bunch of stuff.
snip
> About the E-bus switch instead of a diode - Yep, my experience is
> automotive alternator diodes. Plus one that shorted on a ckt board in
> an A-7 "Big Eight" test station ($1 million for each of the 8 test
> stations) - cost about $100,000 in parts after the unprotected failure
> cascaded throughout the test station and took out about all of its
> electrical guts.
One thing to consider about diodes... If you are planning to have an
alternator at all... you have to have a rectifier of some sort, and those
are most often implemented using... diodes. So you're stuck.
Another thing to consider about diodes... I wonder if the diodes on
the A-7 (Corsair?) test station were solid state or tube. Further, I could
imagine that they likely were fab'ed using an ancient process, much
more prone to failure. Any ideas?
> - The point about heat affecting the auto alternator diodes - vs
> very
> benign environment for the E-bus diode - is well taken. I'll go with
> the diode (and maybe put a "knife blade" switch in parallel in case the
> diode shorts or opens - no, just kidding).
>
> Thanks again for the help
>
> David
>
snip
Back to work!
MAP
Message 25
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| Subject: | Re: 0.70 RCVD_BY_IP Received by |
mail server with no name 1.16 MISSING_SUBJECT Missing Subject: header
--> AeroElectric-List message posted by: Chris Krieg <rv6a@mac.com>
Please look a few lines down in all emails. There is an "unsubscribe"
link.
On Sep 2, 2004, at 2:31 PM, Tracy wrote:
> --> AeroElectric-List message posted by: Tracy <tracyinva@gmail.com>
>
> please take me off this list!!
>
>
> _-
> =======================================================================
> _-
> =======================================================================
> _-
> =======================================================================
> _-
> =======================================================================
> >
>
>
Message 26
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| Subject: | Re: Z-13 - latest version of |
'simplification'
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
'simplification'
At 04:16 PM 9/2/2004 -0500, you wrote:
>--> AeroElectric-List message posted by: "David Carter"
><dcarter@datarecall.net>
>
>Ken & Phil,
>
>How I love this list. A guy can "try out his budding knowledge" and get
>good technical "educational feedback". Thanks for taking the time to
>explain this stuff beyond my fledgling knowledge.
>
>About the alternator switch - that was a late at night, hastily added item -
>zero thought about anything except running down my battery without a switch
>there. I'll add (re-insert) a standard contactor (as in original Z-13!! or
>lower holding current EV200 by Kilovac mentioned by James Foerster - if
>price can be "refined") or solid state device that can handle the current
>(Eric Jones's)
>
>About the E-bus switch instead of a diode - Yep, my experience is automotive
>alternator diodes. Plus one that shorted on a ckt board in an A-7 "Big
>Eight" test station ($1 million for each of the 8 test stations) - cost
>about $100,000 in parts after the unprotected failure cascaded throughout
>the test station and took out about all of its electrical guts.
> - The point about heat affecting the auto alternator diodes - vs very
>benign environment for the E-bus diode - is well taken. I'll go with the
>diode (and maybe put a "knife blade" switch in parallel in case the diode
>shorts or opens - no, just kidding).
Diodes have been used for major power distribution tasks between
busses on bizjets for 40 years. I remember seeing them on some
20 series Lears. They're the oldest power semiconductor device
in our arsenal of parts . . . quite mature, quite robust when
operated within limits. Alternator rectifier stacks are not good
examples of situations that guarantee operation in-limits 100% of
the time . . .
Numerous folks have suggested a switch to replace the diode . . . seems
they still buy into the "avionics master switch" concept. I've suggested
that they put a switch in series with the diode and leave the diode in
place . . . this prevents one from blowing the e-bus alternate feed
path due to inappropriate placement of switches.
Bob . . .
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