nuckolls.bob(at)aeroelect
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 Posted: Sun Dec 15, 2019 1:12 pm Post subject: Questions as I Design My Circuit Diagram |
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At 01:04 PM 12/14/2019, you wrote:
| Quote: | --> AeroElectric-List message posted by: "markfw" <markwheelermd(at)icloud.com>
Bob,
Thank you for your reply.
I changed Z11 in four ways:
1. I am using an EFI system so I enlarged the Endurance Bus to incorporate all of the EFI component circuits |
Okay, in the 'endurance mode' what are your
design goals for battery only operations? The
E-bus plus Battery bus loads generally define
alternator-out loads. Not real clear from
the load analysis narrative.
| Quote: | | 2. I added a Lighting Bus with C/B's just to make wiring the panel easier and because I was out of fuse positions on my Port side fuse block; |
added cbs? Why not another small fuse
block?
| Quote: | | 3. I did not incorporate the E-Bus alternate feed; |
then you don't have an e-bus . . . it's just
an extension of the main bus.
| Quote: | | 4. I used SSR relays rather than contactors. |
Z-11 doesn't care what kind of contactor.
The Z drawings are about architecture and
failure mode effects mitigation.
| Quote: | | I assumed that Z11 was correct. I was only asking about the reasoning about when to use fuses for my own education. |
Very good.
| Quote: | | Does 8AWG wire qualify as "fat" in this context of circuit protection? |
yes
| Quote: | | I will have an O-340 from LyCon as my engine. |
Do you have an otherwise unused vacuum pump
pad? Why not a second alternator?
| Quote: | | My load analysis is attached to this e-mail. |
Do your injectors really draw 1.5A average or
6A for the suite of injectors?
| Quote: | | Joe, I was not asking about a second battery to backup my primary battery. I was asking about it as a way to extend my flight time in the Alternator Out situation. With my EFI my ALT OUT cruise power consumption is 20A so a 7 pound ETX1200 battery would give me approximately an hour of flight time, which should work for most of my needs. I was just exploring what it would take to add in a second battery for certain higher risk trips over water or mountains so I would not have to carry that extra weight all of the time. |
An pad-driven alternator would easily carry
your anticipated system loads, have a lower
cost of ownership than a second battery. The
'e bus' goes away. Would recommend a battery
bus that would support all vital engine functions
so that the panel could be made 'max dark' without
killing the engine.
We would sure like to see a schematic
of this system. Schematics are the fundamental
language for FFA (Function and Failure Analysis).
It appears that you have a 50A b-lead breaker
on the panel? That hasn't been done on most TC
aircraft in decades . . . it's not illustrated
on any z-figure.
You speak to an 'essential bus' but with
no narrative or schematic as to how this
bus gets isolated for energy management
in an alternator-out condition?
Bob . . .
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