Today's Message Index:
----------------------
1. 05:06 AM - Re: Dual alternators (Peter Pengilly)
2. 09:20 AM - Re: Is there a switch configuration that will do this? (Robert L. Nuckolls, III)
3. 10:02 AM - Re: Dual alternators (Robert L. Nuckolls, III)
4. 01:39 PM - Re: Dual alternators (Peter Pengilly)
5. 01:57 PM - Re: Dual alternators (Robert L. Nuckolls, III)
6. 02:17 PM - Re: Dual alternators (Robert L. Nuckolls, III)
Message 1
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| Subject: | Dual alternators |
The whole AMM is downloadable and is in ATA100 format.
DA42 with Continental engines
http://support.diamond-air.at/fileadmin/uploads/files/after_sales_support
/DA42_Twin_Star/Airplane_Maintenance_Manual/Basic_Manual/70201-DA42-AMM-r
4.pdf
See page 24-30-00 (pdf p 567) and on. Wiring diagrams Ch 92, p2077 & on
DA42 with Austro engines
http://support.diamond-air.at/fileadmin/uploads/files/after_sales_support
/DA42_New_Generation/Airplane_Maintenance_Manual/Basic_Manual/70215-DA42-
NG-AMM-r4.pdf
See page 613
DA62 (Austro)
http://support.diamond-air.at/fileadmin/uploads/files/after_sales_support
/DA62/Airplane_Maintenance_Manual/Basic_Manual/70225-r1-complete.pdf
pdf p 525
None of these is very specific. I will look in the engine manuals next
week.
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Robert L.
Nuckolls, III
Sent: 18 June 2021 21:28
Subject: RE: AeroElectric-List: Dual alternators
At 02:48 PM 6/18/2021, you wrote:
In Diamond twins one regulator is the master and has the job of
balancing the alternators.
I=C3=A2=82=AC=84=A2m not actually sure how it achieves that, but
works well most of the time.
Is there a .pdf of the alternator wiring you could
share? Sounds like an interesting system I'd like
to understand.
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 2
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| Subject: | Re: Is there a switch configuration that will do |
this?
At 04:58 PM 6/17/2021, you wrote:
> >> There MIGHT be a simple way to do this but it
> >> =C2 depends on the 'pull down' current of the electrical
> >> =C2 controller. Is there a spec for that device that speaks
> >> =C2 to parameters of this input?
>
>Here's what I was able to find in the
>installation=C2 manual: (top of page 26-8, or page 342 in Acrobat Reader)
>
><https://static.garmin.com/pumac/190-01115-01_an.pdf>https://static.garmin.
com/pumac/190-01115-01_an.pdf
>
>These active-low discrete inputs conform to the following specification:
>Low: Vin < 3.5 VDC, or Rin < 375 =CE=A9 (input active)
>High: Vin > 8 VDC, or Rin> 100k =CE=A9 (input inactive)
Aha! Exactly what was needed. The 3.5v or 375 Ohms
suggests that pull-down current at the switch point
is on the order of 0.01 amps (10 milliAmps).
The 375 Ohms number is handy, let's consider a
270 ohm, 2W resistor as an always-connected, pull-down
value on this input.
To deactivate that input we need to apply bus
voltage from the landing/taxi lights management
switch.
The switches you cited are the Carling line
of devices. A manufacturer favored by Cessna
since the 60s. The full range of functions is
offered by B&C at https://bandc.com
The one you want is the S700-2-10 which is
a progressive transfer, on-on-on function
illustrated by this schematic from the switches
chapter of the 'Connection.
This switch with addition of two
diodes and the resistor cited above can be configured
to accomplish the switching functions you requested.
See attached:
Lower position applies disable signal to
landing/wig-wag controller. Mid position
applies power to taxi lights while maintaining
the landing/wig-wag disable. Upper position
removes power from taxi lights -AND- landing/
wig-wag disable.
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: | Dual alternators |
At 07:05 AM 6/19/2021, you wrote:
>The whole AMM is downloadable and is in ATA100 format.
>
>
snip
>None of these is very specific. I will look in the engine manuals next week.
You got that right! It's been a long time since
I did an ATA100 manual. I was still at Electro-Mech
so this would have been about 1980. I got 'dinged'
for 'too complex', Symptom/Cause/Fix trouble shooting
charts. I can see that the authors of these manuals
were not at risk for similar debasement!
Found a schematic for the left alternator where
the regulator appears to be a paralleling regulator;
data from sensors on both alternators is supplied
to the regulator. Didn't find anything on how the
right alternator differed.
Man! That's a really 'busy' electrical system.
It would be interesting to see the wiring diagrams.
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 4
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| Subject: | Dual alternators |
I think the right side regulator is the same box but the current sensor is
driven from the LH box, will confirm on Monday.
Wiring diagrams are in Ch92 at the end of the book.
Peter
From: owner-aeroelectric-list-server@matronics.com
<owner-aeroelectric-list-server@matronics.com> On Behalf Of Robert L.
Nuckolls, III
Sent: 19 June 2021 18:02
Subject: RE: AeroElectric-List: Dual alternators
At 07:05 AM 6/19/2021, you wrote:
The whole AMM is downloadable and is in ATA100 format.
snip
None of these is very specific. I will look in the engine manuals next week.
You got that right! It's been a long time since
I did an ATA100 manual. I was still at Electro-Mech
so this would have been about 1980. I got 'dinged'
for 'too complex', Symptom/Cause/Fix trouble shooting
charts. I can see that the authors of these manuals
were not at risk for similar debasement!
Found a schematic for the left alternator where
the regulator appears to be a paralleling regulator;
data from sensors on both alternators is supplied
to the regulator. Didn't find anything on how the
right alternator differed.
Man! That's a really 'busy' electrical system.
It would be interesting to see the wiring diagrams.
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 5
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| Subject: | Dual alternators |
>
> Man! That's a really 'busy' electrical system.
> It would be interesting to see the wiring diagrams.
Found them. It will take a bit to sift out
the features of interest . . .
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 6
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| Subject: | Dual alternators |
At 03:38 PM 6/19/2021, you wrote:
>I think the right side regulator is the same box but the current
>sensor is driven from the LH box, will confirm on Monday.
>
>Wiring diagrams are in Ch92 at the end of the book.
Yup . . . found 'em. I think this paralleling system is
of the same genre' as that I proposed to Cessna for
the C303. Only one regulator is fitted with paralleling
smarts. The other is a plain vanilla stand-alone
device.
Stand alone regulator is set for 'nominal' bus
voltage, say 28.5V.
Second regulator watches current from each
alternator and adjusts its own output to
match it's partner with the stand-alone
system.
The paralleling circuit steering authority is limited
to about plus/minus 0.5V. Setup says adjust each
system independently for nominal set-point. Then
operate normally as a dual system.
Both systems retain their redundancy independence
with limited but adequate ability to run in
lockstep with each other.
I thought it would work pretty good . . . never
had a chance to explore it in working hardware.
Today we would enjoy the benefits of hall-effect
sensors for current monitoring . . . back then
I had to look at shunts with a rather energetic
hat-dance to resolve alternator current signals
from the bus common mode noise.
Bob . . .
Un impeachable logic: George Carlin asked, "If black boxes
survive crashes, why don't they make the whole airplane
out of that stuff?"
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