Today's Message Index:
----------------------
1. 01:22 AM - Re: Re: Filter for Hand held devices (Jay Hyde)
2. 07:29 AM - Shunt Readings (Speedy11@aol.com)
3. 07:32 AM - Re: Aerobatics and Instrument Damage (Hinde, Frank George (Corvallis))
4. 08:18 AM - Re: Shunt Readings (Robert L. Nuckolls, III)
5. 06:20 PM - Re: Smart Start wire size (rvg8tor)
6. 07:43 PM - What size wire? (rvg8tor)
Message 1
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| Subject: | Re: Filter for Hand held devices |
Duh.. scratch that question- its says exactly that on the Radio Shack page;
just noticed now...
I'll provide some feedback when I get the transformer
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jay Hyde
Sent: 22 September 2009 08:06 AM
Subject: RE: AeroElectric-List: Re: Filter for Hand held devices
Thanks Bob,
That does make sense; I had isolated it to the dc/dc converter in the same
manner that you suggest here- by powering the device internally. I knew
that it wasn't alternator noise since I was running off the a/c battery
only. I then found out that the same noise has presented itself on another
installation that I did, so it couldn't be installation specific. There the
owner simply let the Ipod charge up and then disconnected it from the system
and played the music into the audio system using the Ipod internal battery.
I'll try and get an isolation transformer here and see what effect that has;
it is simply a transformer with a 1:1 winding ratio?
Jay
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: 21 September 2009 10:35 PM
Subject: RE: AeroElectric-List: Re: Filter for Hand held devices
<nuckolls.bob@aeroelectric.com>
At 08:11 AM 9/14/2009, you wrote:
>
>I think that I do need one; I am using a cigarette lighter type connection
>to power an Ipod power supply. When I connect this to the Ipod no noise is
>heard, but when I connect the Ipod to the radio/ intercom system I
>immediately get a high pitched noise in the earphones.
Okay, 'high pitched' is not alternator noise. It
MIGHT be an artifact of the dc/dc converter in your
ipod power adapter. Try first to power the Ipod internally
without the adapter. Does the noise go away? Try powering
the adapter fromits own 12 battery pack NOT connected to the a/c
in any way. A couple of el-cheeso 6v lantern batteries in
series a good diagnostic supply.
> I separated the
>power and signal leads and the noise stayed. I moved the power supply of
>the cigarette/ Ipod charger directly to the battery and the noise stayed.
I
>will still try a twisted pair on the power supply to the radio/intercom but
>it seems to me that the noise is generated by the Ipod charger so I thought
>that a filter might do the trick. Perhaps even a ferrite bead on the
>positive in to the radio will work.
>
>The only other thing that I can think of is that the loop formed by the
>plug->Ipod charger->Ipod audio out->radio/intercom is somehow causing the
>problem; but how does one get rid of that loop- its intrinsic to the music
>input?
It's most likely to be a ground loop issue which will be
re-enforced or denied by the above experiments.
In any case, it's almost a certainty that filtering
is not solution for root cause.
We may have to incorporate an isolation transformer
where audio from your Ipod goes to one winding and
audio to the ship's system is taken from the other
winding. See:
http://www.radioshack.com/product/index.jsp?productId=2103994
Bob . . .
Message 2
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Bob or somebody -
Please verify (or debunk) what I perceive is happening with the readings
from my shunt.
Background:
RV-8A
Two busses - main (operates everything normally) and standby (operates
essentials if alt + main fail)
One alternator, two batteries - one fore (main batt - main bus + engine
start) & one aft (stby bus - no start)
HE device on wire from alternator to main batt (HE device and main batt
located aft of firewall)
Shunt on standby batt located aft of rear baggage. Battery power is wired
to shunt. Shunt is wired to contactor. Contactor is wired to standby
bus. So, all electrons pass from battery through shunt to contactor to bus.
When I turn on only standby batt contactor, the shunt load indicates about
2A (contactor resistance plus operation of engine monitor).
After engine start and the alternator is carrying the load and the batts
have recharged, I occasionally get a negative amp indication on the shunt
(most of the time the shunt indicates 1 amp - probably contactor).
Question:
Can I assume that when the standby battery is being charged the shunt will
indicate negative amps?
If not, what might cause a negative load indication on the shunt?
Thanks,
Stan Sutterfield
Message 3
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| Subject: | Aerobatics and Instrument Damage |
Absolutely you should..Having said that the RV is a relatively gentle areob
atic airplane. Then again you have an IFR airplane..You really need your in
struments.
One option is to plan an upgrade to a Dynon D100 and a trutrack A/P..These
units are aerobatic proof..ask me how I know...:)
Oh and the RV 7 will spin inverted..:)
Frank
________________________________
From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectr
ic-list-server@matronics.com] On Behalf Of PeterHunt1@aol.com
Sent: Monday, September 21, 2009 7:20 PM
nics.com
Subject: AeroElectric-List: Aerobatics and Instrument Damage
I have completed some excellent Unusual Attitude training in a Cap-10 which
included loops, rolls and spins and will soon complete additional aerobati
c training. Then I would like to try some of these aerobatics maneuvers in
my RV-6. However, I am a little concern that the gyro tumbling and/or G f
orces of aerobatics may hurt my instruments. I have an AI, HSI and S-TEC a
utopilot all containing electric gyros and would hate to damage them. What
has been your experience with aerobatics and instrument damage? Should I
be concerned about this?
Pete in Clearwater
RV-6, Day/night IFR, Reserve Grand Champion S 'n F
Message 4
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| Subject: | Re: Shunt Readings |
>
>Question:
>Can I assume that when the standby battery is being charged the
>shunt will indicate negative amps?
>If not, what might cause a negative load indication on the shunt?
Without seeing power distribution diagram, I can't
be real sure that I have an accurate mental image
of your system's configuration. However, some general
rules apply to battery ammeters . . .
Depending on polarity of connections to the current
sensor (in this case it's not a 'shunt'), the polarity
of current readings will indicate either a charge (bus
voltage above 13v) or a discharge (bus voltage
below 13v). Your narrative seems to indicate that your
battery current display is positive sign when the
battery is being discharged; alternator(s) off.
It follows then that when the alternator(s) lift the
bus voltage to nominal set points, the battery will
be recharged and the sign of battery current will
reverse . . . in this case be (-).
Bob . . .
---------------------------------------
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
---------------------------------------
Message 5
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| Subject: | Re: Smart Start wire size |
I received an email from Bob Newman at TCW, although they have had no issues with
the system the discussion on this board made them double check the the fuse
requirements and after consulting with some starter contact manufacturers they
have upped the fuse requirement to a 5 amps. The on-line version of the manual
is updated. It seems a 3 amp fuse would be fine but since the wire size will
accommodate the 5 amp fuse they are making the change to 5 amps.
--------
Mike "Nemo" Elliott
RV-8A QB (Fuselage)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=264423#264423
Message 6
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Bare with me I am learning! My system will follow Z12, but it does not list a
AWG for the connection form the battery relay to the main buss and from the main
bus to the E-buss. Some of the drawings show a 6 AWG from the battery relay
to the main bus, but the wire diagram from Van's calls out a 8 AWG. So this
got me to thinking how do I determine the size wire that will go here. I understand
wires sizing to individual components but how does one figure a wire feeding
a bus? Do I take the numbers from my load analysis (only continuous loads)
and use that to size the wire? Does the same theory apply for the wire connecting
the main bus to the E-buss through the diode?
Lastly due to panel space my main buss is going to be in two rows, how do I make
the interconnection between the two, bolt a strip of buss bar material between
the buss that holds the CBs. should I connect the two rows of breakers at
both ends giving a redundant path to the second row. To be clear my main buss
is 2 rows of breakers and the E-buss is one row, for 3 rows total. Thanks for
the help.
--------
Mike "Nemo" Elliott
RV-8A QB (Fuselage)
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=264438#264438
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