Today's Message Index:
----------------------
1. 06:07 AM - Re: CAD software (Robert L. Nuckolls, III)
2. 10:07 AM - Re: The fatwire ground blues . . . (Robert L. Nuckolls, III)
3. 12:37 PM - Audio Iso Amp problem (Fiveonepw@aol.com)
4. 01:15 PM - Crowbar CB "problem" question ()
5. 03:13 PM - Re: Audio Iso Amp problem (Robert L. Nuckolls, III)
6. 03:33 PM - Re: Crowbar CB "problem" question (Robert L. Nuckolls, III)
7. 04:26 PM - Z-11 question for the electrically challenged (joelrhaynes@aol.com)
8. 06:50 PM - Re: Audio Iso Amp problem (Charlie England)
Message 1
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| Subject: | Re: CAD software |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 06:47 AM 8/2/2005 +0100, you wrote:
>--> AeroElectric-List message posted by: "Steve Sampson"
><SSampson.SLN21@london.edu>
>
>Bob - before my machine crashed i had some simple software to read and
>modify Z-11 for instance. I had downloaded it from a reference on your web
>site. Cant find it now. Can you point me to the downloads.
http://www.aeroelectric.com/CD/AEC8_0.zip
Bob . . .
Message 2
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| Subject: | Re: The fatwire ground blues . . . |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 05:52 PM 8/2/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: <bakerocb@cox.net>
>
>
>--> AeroElectric-List message previously posted by: "Robert L. Nuckolls,
>III" <nuckollsr@cox.net>
>
>
> >Comments/Questions: I am implementing your dual alt/batt/buss system on my
> >GA-III. I fried a ground wire(lots of smoke)due to a loose battery ground
> >connection while cranking the starter! The fried wire went to the fuel
> >flow sensor mounted on the engine block. The starter return current tried
> >to use the smaller wire due to a loose battery ground connector to the
> >Alt-Battery. Should the sensors(Vision Micro) mounted on the engine block
> >(fuel flow, fuel press, oil temp, oil press) have ground wires that
> >connect to the engine block? These wires can be potential return paths for
> >heavy starter current with a loose (-) battery connection.
>
>8/2/2005
>
>Hello Bob Nuckolls, I am concerned that your correspondent may have bigger
>problems than just a fried wire. I quote from the Vision Microsystems
>installation manual:
>
>"DO NOT: ground the transducer body to any part of the aircraft, if
>possible. Otherwise INSURE that the engine is EXTREMELY well grounded."
>
>Emphasis provided by the author. The manual also contains specific
>directions not to mount some of these transducers directly on the engine.
>
>The wiring diagram for this system shows all wires (which are color coded)
>from these transducers being connected to a specific pin in the DPU (Data
>Processing Unit). I don't know how one could come up with a "ground wire" to
>connect to the engine block.
>
>It is possible that the DPU was damaged while the wire was being fried.
>
>"When (before) all else fails ..... read the instructions".
>
>OC
Very perceptive sir. He DID find another loose ground at
the engine. Root cause wasn't a loose battery ground.
Bob . . .
Message 3
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| Subject: | Audio Iso Amp problem |
--> AeroElectric-List message posted by: Fiveonepw@aol.com
Bob-
My kit-built amp exhibits poor audio input from my Microair 760- the audio is
"clipped?" where perhaps 1/3 of the signal gets through resulting in barely
audible reception. By "clipped" I mean it is like I will hear perhaps 100 msec
of audio with about 200 msec silence between. (WAG at time intervals) The
audio alarm from my EIS4000 engine monitor sounds perfect, however- a nice
clean "beep" simultaneously with the alarm light. I changed the 150 ohm input
resistors with 180s with no noticeable difference.
It is the same unit I sent you for testing some time ago and you reported it
was fine. Autocad dwg of audio system available if desired. Suggestions?
Thanks- Mark Phillips
Message 4
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| Subject: | Crowbar CB "problem" question |
--> AeroElectric-List message posted by: <bakerocb@cox.net>
AeroElectric-List message previously posted by: Richard Riley
<richard@riley.net>
<<For those that have experience with an external regulator -
particularly one of the B&C regulators - how often do the nuisance trips
occur?
If we're worried about the nuisance trips degrading field CB's, would
it be a reasonable fix to replace those CBs at annual?>>
8/3/2005
Hello Richard, 100 hours plus on my plane with an externally regulated
(B&C), gear driven, 60 AMP alternator with no nuisance trips.
Replacing CB's can be a bitch because frequently they are fastened 2 or 3 or
more to a brass bar. It can take a significant amount of unfastening and
then reassembling to replace one CB.
OC
Message 5
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| Subject: | Re: Audio Iso Amp problem |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 03:36 PM 8/3/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: Fiveonepw@aol.com
>
>Bob-
>
>My kit-built amp exhibits poor audio input from my Microair 760- the audio is
>"clipped?" where perhaps 1/3 of the signal gets through resulting in barely
>audible reception. By "clipped" I mean it is like I will hear perhaps 100
>msec
>of audio with about 200 msec silence between. (WAG at time intervals) The
>audio alarm from my EIS4000 engine monitor sounds perfect, however- a nice
>clean "beep" simultaneously with the alarm light. I changed the 150 ohm
>input
>resistors with 180s with no noticeable difference.
>
>It is the same unit I sent you for testing some time ago and you reported it
>was fine. Autocad dwg of audio system available if desired. Suggestions?
Any changes to the series input resistors should be made in 1x/0.5x steps.
For example, if you want to reduce gain of any one channel, the MINIMUM
useful increase would be from 150 to 300 ohms. If still too hot, go to
600 ohms, etc.
By the same token, if you need more gain, reduce a 150 ohm resistor
to 75 ohms first, then 36 ohms.
I'm hearing that some radios like to be "loaded" heavier on their
phones output signals than what the amplifier provides. Before you
change the 180 to anything else, try putting anything from 50 to
100 ohms ACROSS the Microair 760's headphones output leads.
What your describing sounds more like some kind of bias shift
than overloading. The "dummy" load may help more than anything
else. Let us know what you find.
I've had some good feedback from about a dozen builders of the
audio isolation amplifier with some suggestions for improvements.
I'm considering a second generation version . . . but to fit in
the same package, we'll have to go surface mounted parts which
is probably more than most builders want to tackle. If we do
it, the amplifier will offered as a plug-n-play assembly.
There's one going into a certified ship under a 337 installed
by what appears to be a really savvy technician. I asked him
to feed back impressions and suggestions too. I think this
gizmo is ripe for an upgrade but there's no reason we can't
make it do what you need done.
Bob . . .
Message 6
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| Subject: | Re: Crowbar CB "problem" question |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 04:15 PM 8/3/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: <bakerocb@cox.net>
>
>AeroElectric-List message previously posted by: Richard Riley
><richard@riley.net>
>
><<For those that have experience with an external regulator -
>particularly one of the B&C regulators - how often do the nuisance trips
>occur?
>
>If we're worried about the nuisance trips degrading field CB's, would
>it be a reasonable fix to replace those CBs at annual?>>
>
>8/3/2005
>
>Hello Richard, 100 hours plus on my plane with an externally regulated
>(B&C), gear driven, 60 AMP alternator with no nuisance trips.
>
>Replacing CB's can be a bitch because frequently they are fastened 2 or 3 or
>more to a brass bar. It can take a significant amount of unfastening and
>then reassembling to replace one CB.
If one uses fuseblocks for all circuits EXCECPT the
alternator control lead as depicted in the Z-figures, then
a single breaker is usually very easy to replace. But if one uses
a reasonably robust breaker as described in previous posts,
risk to the breaker is WAY down on one's list of maintenance
concerns and then only after experiencing a bucket full of
nuisance trips.
Let's FIX the nuisance trips for the sake of our breakers,
nerves AND good consumer/supplier relationships.
Bob . . .
Message 7
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| Subject: | Z-11 question for the electrically challenged |
--> AeroElectric-List message posted by: joelrhaynes@aol.com
Bob,
I will shortly be wiring my RV-7a according to your Z-11 schematic and will be
using Van's internally regulated 60 amp alternator. If I choose not to employ
OV protection, I assume that I simply connect terminal #4 of the Battery/Alt
switch depicted on Z-11 to the field terminal of the alternator with a fuse (5A?)
in between. Please advise if I am in error.
Also, I gather from recent bandwidth that during normal operation, one should avoid
switching the alternator off until the engine has shut down as this may be
unhealthy for Van's alternator (or perhaps all alternators?).
I know from flying Cessnas that occasionally the alternator will trip out and can
be brought back on line via cycling of the alt switch. Will that scenario
apply in your Z-11 schematic with an internally regulated alternator?
TIA for your help.
Joel Haynes
Bozeman, MT
Message 8
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| Subject: | Re: Audio Iso Amp problem |
--> AeroElectric-List message posted by: Charlie England <ceengland@bellsouth.net>
Fiveonepw@aol.com wrote:
>--> AeroElectric-List message posted by: Fiveonepw@aol.com
>
>Bob-
>
>My kit-built amp exhibits poor audio input from my Microair 760- the audio is
>"clipped?" where perhaps 1/3 of the signal gets through resulting in barely
>audible reception. By "clipped" I mean it is like I will hear perhaps 100 msec
>of audio with about 200 msec silence between. (WAG at time intervals) The
>audio alarm from my EIS4000 engine monitor sounds perfect, however- a nice
>clean "beep" simultaneously with the alarm light. I changed the 150 ohm input
>resistors with 180s with no noticeable difference.
>
>It is the same unit I sent you for testing some time ago and you reported it
>was fine. Autocad dwg of audio system available if desired. Suggestions?
>
>Thanks- Mark Phillips
>
You might check with an ohm meter from each input terminal on the amp to
ground (with everything still hooked up but not powered up). The
behavior of the 760 sounds like a current limiting circuit in an audio
output stage might be trying to protect it from overload. I don't have
the schematic in front of me but would expect to see at least 200 ohms
from input to ground on each input.
Charlie
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