nuckolls.bob(at)aeroelect
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 Posted: Tue Jul 14, 2009 5:26 am Post subject: Z-19 Future Plans for use with Eggenfellner Engine |
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At 04:56 PM 7/13/2009, you wrote:
Considering that AEC 9005-101 is no more and that AEC 9011-100-1
The 9005 product included a power transistor suited to the
direct control of the aux battery contactor . . .
which encouraged the use of a 2-10 style switch
for aux battery master. In the interest of simplicity
I went to simple annunciation of low aux battery voltage
-AND- a simpler switch to control it.
If you want an automatic management feature, you can
use the ABMM product from
http://www.periheliondesign.com/
or built from scratch as described on my website.
I really like the capability of what the 9011
will do for not only control and enunciation of
OV but also the monitoring of LV for
2 electrical busses. (A side note – the REV B
02-04-06 drawing for the 9011 device shows a redundant #6 connection).
Yeah, there's a couple of things that need fixing.
Note too that the 9011 has a LOT of features just because
we can put them in for little if any extra cost.
On can use all or any combination of the features
depending on design goals. For example, it's not
a great "waste" to use a 9011 as a simple, single
channel LV warning. The basic 9011 package, warning
lights, and OV relay will be separately offered
products.
If the internally regulated alternator used with
this system is like the Plane Power and the
Enable/Field connection carries the field current
(as indicated in ‘Lectric Bob’s correspondence
with plane power), I assume the following:
AEC9004 is not needed with the AEC 9011.
Correct. The AEC9004 allows builders to install
ANY internally regulated alternator and exercise
any time, any conditions ON/OFF control while
achieving the legacy design goals for independent
monitoring and control for OV conditions. It's
use is dictated by the internally regulated alternator.
The 9011 would still be used for LV annunciation
in all cases where that feature is not offered in
other accessories.
The Special Disconnect Relay will break the field
connection, which would be powered to the relay
from the 5A.CB and back to the ALT On Switch.
Yes. Note that the relay was re-incorporated
so that the 9011 can be used with EITHER alternators
or generators.
The N.O. terminal on the Disconnect Relay, could
be connected to ground. This would open the
5A.CB when the relay was activated. This is
redundant, I am sure. But can it hurt? Does
tripping of the 5A.CB at the time of every
pre-flight test/reset series cause a problem?
No need to do this. The microprocessor in the 9011
latches the relay to keep the alternator/generator
off line. The OV trip light (if installed) will
illuminate. The LV warning lights (if installed)
will begin to complain shortly thereafter.
If the internally regulated alternator is not as
above and the field current cannot be broken; I
assume that this is where AEC 9004 is
needed. How is this integrated into the above?
Yes, the AEC9004 is used on internally regulated alternators
only.
Two other related questions:
I understand that Jan Eggenfellner recommends
that both main batteries should be used in
parallel during an engine start. Is there any
reason that a “Brown-Out” addition should not be
considered as was done in converting Z-13/8 to
Z-10/8? It only adds cost/weight of one more
small battery and one more small relay. A side
benefit is that this would add somewhat to the alternator out flight duration.
Depends on your installed equipment and design
goals. If you have electro-whizzies that you intend
to power up before starting that do not tolerate
brown-outs, then keeping one battery out of the
cranking loop is required. If you start up such
devices only after the engine is started, then
using both batteries to crank is fine . . . but
either battery should be capable of starting
an engine.
In looking at Eggenfellner’s most current
recommendation for the electrical power system to
be used with his engines, I would like to
consider the following: Instead of one 4PDT
switch to the engine, it makes sense to me to
have 2 4PST switches through a double power diode
to each of the 4 essential engine items (the 4th
for me would be the propeller). Eliminate the
“Ignition Switch”. This to me reduces parts
count and eliminates a single point of failure
(double throw switch). Comments?
Single point failure elimination is a design goal
for all well considered Failure Modes Effects
Analysis. Anything you can do to reduce if not
eliminate all "sharing" of components between
primary and backup systems is a good thing to do.
Bob . . .
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