Today's Message Index:
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1. 07:12 AM - Re: How to wire a LED to a LR3C (Robert L. Nuckolls, III)
2. 07:27 AM - Re: Re: dual bus, single battery (Robert L. Nuckolls, III)
3. 09:34 AM - New Z-8 drawing (Robert L. Nuckolls, III)
4. 10:56 AM - Re: E-Bus Off/On Indicator Light (D)
5. 11:26 AM - Power Schematic for Review (Gordon Smith)
6. 04:11 PM - Re: New Z-8 drawing (rckol)
7. 08:23 PM - Re: Re: New Z-8 drawing (Robert L. Nuckolls, III)
Message 1
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Subject: | Re: How to wire a LED to a LR3C |
At 12:56 AM 7/30/2010, you wrote:
><rparigor@suffolk.lib.ny.us>
>
>Hi Bob
>
>I have selected a yellow LED to be used with my 12V LR3C.
>
>It came from Pep boys wired with a 680 ohm resistor and works quite
>well on 12 volts.
>
>The reason I like it's very bright and doesn't have a flange at the
>bottom and is longer than normal which allows me to have it extend a
>little bit from panel which can get my attention even though it is
>located above my knees because the semiconductor point is in fact in my view.
>
>Question is since 680 ohms is a bit more resistance that I normally
>use to drop 12 volts to run a yellow LED, does your suggestion of
>installing two 220 ohm resistors (one in series and one in parallel)
>hold true for this LED? Or perhaps up the ohms a little?
If the intensity is okay with the as-supplied
resistor, just parallel the lamp assembly with
sufficiently low resistant to prevent a tiny
bit of glow when the LR3 is NOT flashing the
light. There's a few milliamps of current flowing
in a dark lamp on the LR3's lamp driver output
that won't get any light out of a filament but
will illuminate an led. You just need to swamp
out the effects of this bias current to keep
the led dark.
Bob . . .
Message 2
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Subject: | Re: dual bus, single battery |
>I thought I understood all of the heartburn about the AMS switch
>after reading the connection and some supplementary articles on the
>website... Am I still missing something?
Probably not. The design goals behind the Z-figures is to
minimize weight, complexity, cost and risk. I.e. the
elegant solution. Beyond that, one can make any number
of variations to suit personal tastes . . . it's like
picking paint colors and upholstery fabric. The only
caveat is to be sensitive to increases in risk . . .
which may be perfectly acceptable . . . it's your
choice.
>Keep the thoughts coming, though; I haven't quite convinced myself
>that I should let convenience drive my architecture as opposed to
>some other factor (like fast load shedding!).
Speed in the load shedding activity is not a big
design driver. If you finished a cup of coffee with
the low voltage light flashing, it probably wouldn't
make any difference in the outcome of your flight.
Other than smoke in the cockpit or sparks from a
radio, no electrical failure is cause for heroic
action.
My advice to builders over the years is to take
a Z-figure (mature and well examined over the
years) that most closely meets your needs and
then identify shortfalls that my be unique to
your needs and desires.
If the shortfalls are just matters of preference
and do not drive risk to unacceptable levels,
why not modify accordingly? What we cannot do
as an advisory group is put weight on preferences
nor willingness to accept risk. We can't even
put numbers on risk.
All that can be said about the Z-figures is that
they've been pondered and proven over the past
20 years or so and offer comfortable recipes
for success. The Z-figures are not the ONLY
recipes for success. But a NEW recipe necessarily
starts the proofing task over.
Bob . . .
Message 3
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Discussions with Jon Laury combined with conversation
about the abortive Z-13/8 architecture some months
ago have prompted a new Z-figure.
http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z08A-PRELIMINARY.pdf
Design goals include but are not limited to
Fuseblock-friendly design (crowbar ov protection
replaced with new field disconnect relay system.
Two layer electrical system similar to that crafted
in Z-13/8.
No practical limit to the size of the aux alternator.
Anything from the SD-20 on up can be adapted to this
architecture.
Single battery.
This architecture seems well suited to electrically
dependent engines where demand for energy exceeds
what an SD-8 can supply. The two-layer architecture
(as opposed to single-layer like Z-12) offers a way
to make the majority of the ship's electrical system
completely cold while maintaining engine operations.
I'm still pondering the ingredients that might work
best in this recipe for success. Thought I would share
it with the group. It's a good example of how new
and useful things can evolve from a group of folks
willing to throw some stuff against the wall to see
what sticks!
Bob . . .
Message 4
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Subject: | Re: E-Bus Off/On Indicator Light |
For what it's worth, I plan to put my nav/strobes (probably of the LED
variety) on my E-bus as just such a reminder. Pretty hard to miss the
strobes flashing as you give the plane a last look before walking away.
Dan
Message 5
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Subject: | Power Schematic for Review |
I have laid out a preliminary electrical system schematic for an all metal
aircraft (Sonex) powered by a Jabiru 3300 engine. I would appreciate Bob's
and other lister's comments. I have not yet done a complete Bus Load
analysis so some of the wire sizes, fuse sizes and other options could
change. I have not included the ignition systems in that they are totally
independent of the aircraft electrical system.
In considering the possible Z figures, I found that Z20 (small Jabiru) and
Z21 (J3300) did not quite offer what I was hoping to accomplish. I believe
that Z16 (Rotax 912/914) offered what I would like to have as a basis.
Even though we have been cautioned about cherry picking the various Z
figures, there are some features in other Z figures that I would like to
incorporate.
* First, I would like to incorporate the soon to be available AEC9024
device for control of the master contactor, the OV disconnect relay and as a
LV warning device. I cherry picked this from Z09 and Z-Laury. I might not
have the pin-outs correct, but that can be updated easily at a later time,
when the specs are published. I like the idea of a "Breaker-less" panel.
* I would like to use the JD101406 Rectifier/Regulator, as in Z09, in
place of the Jabiru supplied unit. I understand that this might be a more
robust option.
* I would like to have the Alternator OV Disconnect Relay to Open one
of the Dynamo leads as in Z16 instead of the +B lead as in Z21.
* There are two other major options that I would like to consider:
1. BROWNOUT BATTERY WITH B/O RELAY. This as is illustrated in Z10-8.
I am considering a MGL EFIS system. They (and others, I believe) offer an
option to use a backup battery that is exclusive to powering the EFIS and
its accessories. I think that a well designed and crafted E-Bus system
makes this exclusive backup unnecessary and redundant. The exclusive backup
battery cannot be kept charged unless turned "ON" during operation of the
EFIS from the main power source. The Z-10-8 type of backup not only offers
a seamless full voltage for ALL E-Bus items, during cranking to start, but
adds to the alternator out E-Bus operating time capacity. It will also be
topped off and maintained automatically when the main battery is connected
to a remote maintainer through the Aux. 12V. Power plug in the panel.
2. E-BUS ALTERNATE FEED RELAY. This as in Z32. In that I have not
finalized the calculation of the E-Bus loads, this may or may not be needed.
What is the continuous (and intermittent) E-Bus amperage point at which the
relay should be implemented? I have incorporated a LED light indicator to
show that the E-Bus feed is closed (ON) in any case.
The other thing that needs to be reviewed is the use of FUSEABLELINKS. We
have also been cautioned to not incorporate them accept in special
considerations so please comment:
* Fuseablelink in the alternator +B lead at the starter contactor as
in Z16, Z18, Z20 and in the alt alternator +B lead to the hot side of the
main battery contactor of Z8.
* Fuseablelink in the E-Bus alternate feed path at the connection to
the E-Bus as in Z13-8 and Z13-8 E-Bus Feeders.
* Fuseablelink in the E-Bus alternate feed from the hot side of the
battery contactor as in Z16 and Z18.
* Fuseablelink at the B/O battery hot lead to the E-Bus alt. feed
relay or switch. In this use I could not find illustration in the Z
figures. However I think that it might be logical to assume that this use
is OK if the use mentioned directly above from the hot side of the main
battery is OK.
I have attached a four page illustration that shows all options. The first
page (D) shows the inclusion of both options. Next (C) and (B) illustrate
the two options implemented singly. The last page (A) includes neither
option.
Gordon Smith
Message 6
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Subject: | Re: New Z-8 drawing |
I might be missing something here, but it seems that unlike the Z13/8, if the battery
contactor is open, only the battery bus will be fed by the aux alt (no
feed for equipment that might be on a traditional ebus, like minimal pfd, nav
and comm).
Is this the intent, or do these other functions get piled into the battery bus?
--------
rck
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=306868#306868
Message 7
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Subject: | Re: New Z-8 drawing |
At 06:09 PM 7/30/2010, you wrote:
>
>I might be missing something here, but it seems that unlike the
>Z13/8, if the battery contactor is open, only the battery bus will
>be fed by the aux alt (no feed for equipment that might be on a
>traditional ebus, like minimal pfd, nav and comm).
>
>Is this the intent, or do these other functions get piled into the
>battery bus?
One could add an e-bus to this architecture . . . and
in fact, I'll do so at the next iteration.
Thanks for bringing it up. I hadn't really got that
far yet . . . the e-bus can be added to virtually
any architecture. I was fixated on getting the fat
wires managed first.
Bob . . .
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