Today's Message Index:
----------------------
1. 07:43 AM - Re: Re: HomeBrew Engine Monitor (Robert L. Nuckolls, III)
2. 08:04 AM - Re: Re: OVM-14 question (Robert L. Nuckolls, III)
3. 08:13 AM - Re: Re: OVM-14 question (Robert L. Nuckolls, III)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: HomeBrew Engine Monitor |
At 08:23 PM 12/4/2019, you wrote:
>
>Well Bob, That's the funny thing. I got so frustrated at the
>schematic tools that I skipped that step, but I'll go back to it
>'cause I know it's the right thing to do. Let me see if I can get
>something that's understandable.
>
>Andy
I suggest that a 'program' is not
necessary and, unless you're really
'salty' with one, clumsiness of
implementation gets in the way of
design deliberations.
Get a tablet of quad-ruled paper,
a #2 pencil, straight edge and a
'pink pearl' eraser.
Sketch your schematic in functionality
blocks. Download this drawing for
an example.
http://www.aeroelectric.com/Misc/9018-600D_DACard_P1.pdf
Here's the signal conditioning card for
a Arduino based DAS system. It took three
pages to define all the functions for an
8 channel i/o shield. Do your design in similar
fashion . . . push and pull the ideas around
on paper with a draw/erase capability that
is probably faster than a CAD program.
When the details are stacked up to a good stopping
point, scan the pages and post to the List.
Then folks here can begin to compare your
handiwork with their own knowledge and
experience for the development of suggestions.
A Pentel 0.9MM HB pencil and Pink Pearl are
my own first-line design tools.
Bob . . .
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: OVM-14 question |
At 10:47 AM 12/4/2019, you wrote:
>
>I choose the Z13/8 instead of the Z12 because I
>have electrical dependent fuel and ignition. The
>Z13 seemed closest to my configuration using the
>Ford regulator rather than the B&C regulator.
??? Z13 vs. Z12 has nothing to do with
the style of regulator or electrical
dependency of engine.
Z-13 is specifically designed to MINIMIZE
endurance loads on a TINY alternator . . .
like the SD8.
>The design concept is based on the article
>listed below. I wanted to have continuous flight
>with least amount of pilot intervention.
>
> >From "Electrical System Reliability=9D 04/00
>Adding an Aux alternator with auto switching
>
>In normal flight both alternators are ON but the
>Aux alternator goes to sleep because it's
>regulator thinks the bus voltage is too high. If
>the main alt fails to support the ships loads,
>the bus voltage sags waking up the Aux Alt.
This narrative does not describe Z-13, it's
talking about Z-12 with a second alternator
driven by an SB-1 regulator (with autoswitch
features). Z-12 is also just fine using an
LR3 (or any other regulator). It just means
you have to flip a couple of switches when
the low-volts warning comes on.
>Reason I have circuit breakers on some items is
>because with a momentary switch, I can short to
>ground items to lighten load, which will trip
>the breakers reducing loads. Then if appropriate
>I can return function to selected items as the
>situation permits, By resetting the individual CB.
>Cost fuse vs CB is not an issue as I have the CB
>already. I=99m also using circuit breaker
>switches for some items and fuse for some other items.
Breaker-switches have a poor track record
in airplanes. They cost Beech a bucket-load
of money when the proved less-than-robust in
about 15 production-years of Bonanzas and Barons.
>My main question is how to get over voltage
>protection to work individually for each
>alternator. It would seem that if one alternator
>went high it would trip both field breakers. I
>think I need to monitor each output before it
>guts to the buss. However I could just let it
>trip both field breakers and the reset on. if it
>trips again reset the other. but that requires more pilot intervention.
Your worries about 'pilot intervention' are
mystifying. One presumes that pilots do things
based on knowledge, experience and planning.
Actions needed to bring a standby alternator on
line are trivial and NOT and emergency. When
the low volts light comes on, your properly
maintained battery will shoulder the loads while
you finish your cup of coffee and turn off the
MP3 player.
>Any reason a low voltage warning light can=99t
>be installed with a resistor of of the terminal
>=9CI=9D of the ford regulator? I think that is what ford does.
>
>
The FORD regulator warning light pin is
next to useless in airplanes. You need one and
only one low volts warning light on the main
bus. If you have an LR3 regulator on your main
alternator, that light is built in. Recommend
you use Z12 and I would discourage the use
of breaker-switches.
Any idea of fiddling with breakers in flight
for load shedding sorta admits that you
don't have a plan-B for abnormal operations.
Z-12 with two FAT alternators say's you'll
never need to do load shedding except for battery-
only ops after having lost both alternators . . .
an exceedingly unlikely condition.
You're going to run out of gas or fly into
convective weather before you loose two
alternators on a single flight.
Your engine loads should run off the
battery bus.
Bob . . .
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: OVM-14 question |
>
>In normal flight both alternators are ON but the Aux alternator goes
>to sleep because it's regulator thinks the bus voltage is too high.
>If the main alt fails to support the ships loads, the bus voltage
>sags waking up the Aux Alt.
P.S. If you're using B&C alternator controllers
in Z-12, the ov control systems are 'selective
trip' . . . when an ov condition is detected,
each ov system looks to see if 'my alternator' has
field voltage on it. If so, then the 'my regulator'
is bad and I trip only 'my alternator'.
If the field voltage is low or zero, the
ov condition is generated by failure of the 'other
regulator' it is expect to manage it's own
shutdown operation.
In an artfully designed multi-alternator system,
it's easy to preclude tripping of both systems
during an ov event.
Bob . . .
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|