Today's Message Index:
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1. 10:35 AM - Z101b with Shunts, Shunts as Fuse Link Junctions (Jared Yates)
2. 10:50 AM - Re: Z101b with Shunts, Shunts as Fuse Link Junctions (Robert L. Nuckolls, III)
3. 12:53 PM - Z101b Wire Gauge question (Jeffrey Cohen)
4. 01:17 PM - Re: Z101b with Shunts, Shunts as Fuse Link Junctions (David Carter)
5. 04:47 PM - Re: Z101b with Shunts, Shunts as Fuse Link Junctions (user9253)
Message 1
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| Subject: | Z101b with Shunts, Shunts as Fuse Link Junctions |
Z101b has a very nice implementation of a single Hall Effect sensor for
both alternator B-leads. The trouble I have is that I don't have an ammeter
that can use a Hall Effect sensor.
I can see a few options. One is to install two shunts and use a DPDT switch
to select which one presents on the ammeter.
If I go this route, is it kosher to integrate the alternator B-lead fuse
link at the shunt? For example, for the main alternator, can I run an 8g
wire from the alternator to one end of the shunt, then on the other end of
the shunt, run a 4" piece of 12g wire to the starter contactor? The same
strategy would work for the standby alternator, with slightly different
numbers and attach points.
Another option is to seek out a stand-alone ammeter that senses with a Hall
Effect Sensor. But that is likely to be more expensive and more work to
integrate at this stage. Is there such a thing?
Thanks!
Jared
Message 2
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| Subject: | Re: Z101b with Shunts, Shunts as Fuse Link Junctions |
At 12:34 PM 3/11/2022, you wrote:
>Z101b has a very nice implementation of a single
>Hall Effect sensor for both alternator B-leads.
>The trouble I have is that I don't have an
>ammeter that can use a Hall Effect sensor.
>
>I can see a few options. One is to install two
>shunts and use a DPDT switch to select which one presents on the ammeter.
=C2
That's how walter beech did it
>If I go this route, is it kosher to integrate
>the alternator B-lead fuse link at the shunt?
>For example, for the main alternator, can I run
>an 8g wire from the alternator to one end of the
>shunt, then on the other end of the shunt, run a
>4" piece of 12g wire to the starter contactor?
>The same strategy would work for the standby
>alternator, with slightly different numbers and attach points.
>
>Another option is to seek out a stand-alone
>ammeter that senses with a Hall Effect Sensor.
>But that is likely to be more expensive and more
>work to integrate at this stage. Is there such a thing?
Probably, but yeah not for price of a big-mac and fries.
Consider putting the ammeter in ONLY the stand-by
alternator. You've done a load analysis . . . yes?
Your main alternator is at zero risk for being
over taxed.
The S/B alternator is limited and would benefit
most from in flight knowledge of present loads.
But it's still not a flight critcal item.
Your plan-b load shedding protocols were
all established during load analysis . . . yes?
You can't overload it at vacuum pump drive pad speeds.
If you did tax beyond capability to sustain bus
voltage, you'll see it on the lo volts warning
and even before, observe it on the panel volts
display.
Panel ammeters are about as useful as foxtails on
your '57 Chevy's radio antenna. Looks cool but
adds no utility. Greatest use for ammeters is
ground diagnostics and there are other ways to
get that data.
I included that feature only because the glass-
cockpit guys include in their products. Why?
Cause they can for very little cost . . . and
it's cooler than a foxtail hanging off your
VHF COMM antenna.
If it were my airplane, I'd do the operational
protocols planning, proof them in flight testing
then rely on active notification of low volts.
Ammeters need not apply.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
Message 3
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| Subject: | Z101b Wire Gauge question |
Thank you for the previous reply post on Fusing. Very helpful. Now for a wire gauge
question.
On Z101b, is there a reason that a 12AWG wire feeds into the NTE53016 Diode, but
a 14AWG wire leads out?
Jeff Cohen
Jcohen@post.com
734-323-7421
Message 4
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| Subject: | Re: Z101b with Shunts, Shunts as Fuse Link Junctions |
I included that feature only because the glass-
cockpit guys include in their products. Why?
Cause they can for very little cost . . .
One thing I've learned as I'm finalizing the avionics interconnects on my
Garmin G3X panel: general-purpose analog-to-digital inputs can be a scarce
commodity, depending on your needs. They are only available on the GEA 24
Engine Indication System box, and there are only 7. (There are separate
dedicated Shunt 1 & Shunt 2 inputs available.) Someone might choose a shunt
over the Hall-effect sensor to free up an A/D input channel. Or go without
current measurement as Bob suggests.
How could you run out of general-purpose A/D inputs?
1 - elevator trim position sensor
2 - aileron trim position sensor
3 - rudder trim position sensor
4 - flaps position sensor
5 - exhaust O2 sensor
6 - timing advance from electronic ignition
7 - bus 1 Hall effect current sensor
8 - bus 1 Hall effect current sensor
9 - cabin CO monitor
10 - pilot SPO2 monitor
11 - O2 bottle pressure sensor
etc.
In my configuration, I'll have the following:
1 - elevator trim position sensor
2 - flaps position sensor
3 - exhaust O2 sensor
4 - timing advance from electronic ignition
5 - Main/Aux alternator current Hall effect sensor
6 - cabin CO monitor
7 - spare (who knows what I'll come up with in the future!)
I'll monitor O2 bottle pressure, pilot blood oxygen level, outside
humidity, and outside dewpoint values via an app on the iPad. (all via
products from Aithre)
---
David Carter
david@carter.net
>
Message 5
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| Subject: | Re: Z101b with Shunts, Shunts as Fuse Link Junctions |
An ammeter is optional. As long as the voltage is above 13.5, you will know that
the alternator is working. The pilot does not need to know how many amps the
alternator is putting out. It is useful to know current for troubleshooting
purposes. Save troubleshooting for when safely on the ground using a handheld
meter. If desired to know amps while airborne, install a shunt on the standby
alternator to help manage loads. There is no need to know amps while the
primary alternator is working.
What kind of EFIS are you going to install? If none, have you considered a GRT
EIS Engine Monitor? I believe it works with a HALL effect sensor.
--------
Joe Gores
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http://forums.matronics.com/viewtopic.php?p=506293#506293
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