Today's Message Index:
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1. 02:58 PM - Re: Fw: Preflight Check List Item - 0.8V (Robert L. Nuckolls, III)
2. 08:19 PM - My Visio 2000 Stencil (Chad Robinson)
Message 1
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| Subject: | Re: Fw: Preflight Check List Item - 0.8V |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <rnuckolls@aeroelectric.com>
At 12:17 PM 7/17/2004 -0600, you wrote:
>--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
>
>Do not archive ----- Original Message -----
>From: Rick Fogerson
>To: aeroelectric-list@matronics.com
>Subject: Preflight Check List Item - 0.8V
>
>
>Hi Bob,
>There was a preflight item you recommended I check on my RV 6A that had to
>do with 0.8 Volts and the essential bus. It's been 5 years since I've
>owned the airplane. Is the test still recommended and if it is could you
>refresh my memory on how the test was done and what it accomplished.
Yes it is. If you have a diode isolated e-bus, then normal
operating voltage for the e-bus is 0.6 to 1.0 volts lower than
the main bus due to diode drop in a standard silicon junction
diode like those illustrated and recommended in drawings found
on the website. During pre-flight, it's recommended that
you use a comm transceiver on the e-bus powered through the
E-BUS ALT FEED (with the DC PWR MASTER - OFF) to get ATIS and
or clearance delivery. If you have a voltmeter on the e-bus
(also recommended) it will be reading present battery voltage.
Compare this reading with reading for known good battery . . .
this is a good preliminary check of battery condition.
After engine is started, you can check the voltmeter again
to see that the alternator has picked up the system . . . and
it should be reading 14.0 to 14.5 volts. Turn the E-BUS alternate
feed switch OFF and voltmeter should drop to perhaps as low as 13.0
volts depending on how much 'stuff' is on your e-bus. This
sequence of switch operations shows that the diode is not
shorted.
If you'd like to reduce this voltage drop to something on the order
of 0.5 to 0.7 volts, you can use what is known as a Schottky diode
to replace the bridge rectifier depicted in my drawings. The
rectifier was chosen not because of its electrical characteristics
but its mechanical characteristics. Very user friendly mounting
and wiring. I've had a couple of builders replace the e-bus
isolation diode with a relay driven from a LV WARN/Ignition Battery
Management Module . . . this drives the voltage drop down still
further but replaces a lifetime solid state part with a relay (ugh!)
and drives up parts count.
Bob . . .
---
Message 2
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| Subject: | My Visio 2000 Stencil |
--> AeroElectric-List message posted by: Chad Robinson <crj@lucubration.com>
Hello all,
I've received numerous requests in the past few days for my Visio stencil of
the AeroElectric symbols. To anybody that may be looking for this file, please
drop by
http://www.lucubration.com/aero
and you can download the file from there. I ask only that you recognize Bob
Nuckolls' original efforts in creating these symbols in AutoCAD, and that if
you make changes to the stencil that you recontribute them so I can post
updated versions for everybody's benefit.
A few comments:
1. To use the stencil you need any edition of Visio 2000 or higher. Save the
stencil somewhere you can find it. Open Visio, create a new drawing, and click
File->Open Stencil. Browse for where you saved the file and select it. Then
drag symbols to your drawing and use the dynamic wire connector to draw wires.
2. You can adjust the thickness of wires and add labels to indicate their wire
sizes. For an example of this, see my diagram in Chapter 22 of the "Orion"
section of my site.
3. When you save and close your drawing, then re-open it, Visio should find
the stencil again as long as you haven't moved it.
4. Some of the symbols aren't quite perfect, especially with respect to the
text labels. Sometimes you have to click once and start typing to change a
label, and sometimes you have to click twice (but NOT double-click, wait a
second between clicks). For an example of this, see the battery or fuse
symbols, or the switches.
Regards,
Chad
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