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1. 10:10 AM - Re: Switch Schemes for Reliability (bobmeyers)
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| Subject: | Re: Switch Schemes for Reliability |
BoB, Quoting from your post...
"I'm increasingly of the opinion that Z-101 should be the ONLY z-figure in any
'upgrade' to the connection"
While I like the concepts in Z-101 I'm not sold on this being the only idea. There
has been a number of posts about incorporating a back up battery in its architecture
which seems counter productive.
While not arguing against Z-101, instead I'm going to argue for Z-14 and possible
additions to it.
Z-14 has been around for a long time and you have a warning in the connections
that it is probably not relavent to 99% of OBAM aircraft.
However, it was crafted at a time when, except for the rado stack, there were very
few electically driven components in the panel. An additional battery also
carried a large weight penalty. Also few electrically dependent engines were
being installed.
These things are no longer true. Most new OBAM aircraft are being built with at
least some flavor of EFIS in the panel as well as supporting any number of supporting
devices for ADSB, iPads etc.
Additionally many non electrically dependent engines are being retrofitted with
an electronic magneto replacement, and many new engine installs are electically
dependant from the start.
New battery technology is beginning to repalce the heavier lead based batteries.
Two lithium batteries easily weigh less than one older style battery.
These developments argue for a fresh look at Z-14. I looked to Z-14 for my latest
aircraft, completed in 2017, before Z-101 was introduced. So I saw many advantages
to Z-14 in comparison to the other Z figures at that time.
First, the Garmin equipment I installed mostly had Two power inputs with diode
isolation meaning power from either bus would feed the component. This in itself
removes the need for brown out prevention in my aircraft as I don't automatically
connect both buses when running the starter.
Operationally it is no more complex than Z-101 if an alternator fails. I recycle
the alternator and if the alternator does not come back on line I simply cross
connect the buses. In my case I have the B&C 40 amp alternator and after derating
it to 30 amps in cruise, it still supplies power to all equipment at less
than 80% of 30 amps.
If you want to argue switch or operational complexity. Z-101 is now as operational
complex as Z-14 with almost as many components.
I do not ignore your admonition to not "FIDDLE WITH STUFF ON THE PANEL" in an emergency.
Z-14 requires only the same management as Z-101 and in my case, no load
shedding concerns.
In my panel I use a couple of bridge rectifiers to provide power from two buses
to a device that only has one power input. All switched devices take power from
one source so not all devices need two sources.
Z-14 could have an engine bus powered from both buses through a bridge rectifier
or some other setup.
If you want to set up Z-101 as a plug and play design I would suggest variations
like this.
Z-101 Single battery and alternator
Z-101 A Single battery and dual alternator
Z-101 B Single battery and dual alternator with an engine bus (current Z-101)
Z-101 C Dual battery and dual alternator
Z-101 D Dual battery and dual alternator with an engine bus
Start with Z-101 and add an option.
Bob, thanks for developing and continuing to develop these wonderful Z drawings.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=513548#513548
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