Today's Message Index:
----------------------
1. 02:40 AM - Re: Single fuse for two fuel guages only (GTH)
2. 06:41 AM - Re: Z13/8 Testimoney (Robert L. Nuckolls, III)
3. 06:47 AM - Dimmers driving displays... (andymeyer)
4. 08:26 AM - Re: Dimmers driving displays... (john Snapp)
5. 08:29 AM - Re: Single fuse for two fuel guages only (Robert L. Nuckolls, III)
6. 08:34 AM - Re: Dimmers driving displays... (Robert L. Nuckolls, III)
7. 08:51 AM - Re: Single fuse for two fuel guages only (Ralph E. Capen)
8. 08:58 AM - Dimmers driving displays (Paul Millner)
9. 09:10 AM - Re: Dimmers driving displays... (Gerald Champagne)
10. 10:56 AM - Re: Dimmers driving displays... (andymeyer)
11. 12:40 PM - Re: Re: Dimmers driving displays... (Daniel Hooper)
12. 01:13 PM - =?utf-8?Q?Re:__Re:_Dimmers_driving_displays...? ()
13. 02:21 PM - Re: BMA Powerboard with Z19RB (Robert L. Nuckolls, III)
14. 02:25 PM - Re: Dimmers driving displays (Robert L. Nuckolls, III)
Message 1
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Subject: | Re: Single fuse for two fuel guages only |
Le 01/04/2015 20:30, Ralph E. Capen a crit :
>
> I have been doing some rearranging of the wiring and circuit protection in my
6A.
>
> I found my two fuel guages ( Vans IE-VFL-15) wired directly to the starter power
input on the key switch (I must have been lazy that day). The documentation
calls for 18AWG wiring for this circuit - but does not specify circuit protection
sizing. I am thinking a 3 amp fuse should allow sufficient current and
provide protection for the wiring.
>
Ralph,
I'm not sure which wire is 18 AWG in your circuit (starter input ? fuel
pump wire ?), but this table maybe of some use :
http://contrails.free.fr/elec_fil_section.php
It shows current ratings against wire gauge.
FWIW,
Best regards,
Gilles
http://contrails.free.fr
Message 2
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Subject: | Re: Z13/8 Testimoney |
At 10:03 2015-04-01, you wrote:
>RV-8A with nearly 500 hours over 4 years flying
>out of Inyokern, CA (IYK). Never any electrical
>issues. Minding my business near Bakersfield
>yesterday setting up for practice approaches
>when I noticed the flashing low voltage light.
>No degrading of capabilities, but voltage going
>down. Flipped two switches Aux Alt ON and END
>Bus ON and electrons started flowing. Turned off
>strobes and headed home with GPS, AFS 4500, IFF,
>SL30 and Tru Trak ADI (my backup attitude indicator) working.
>
>Then noticed Alt Field CB popped. After clearing
>mountains, reset CB and it stayed reset. Went back to main alt power.
>
>Now trying to figure out what happened. Removed
>cowl all wires and connections intact. Greg at
>B&C most helpful so will go through LR3C-14 trouble shooting steps later today.
>
>Anyone on the list have any words of wisdom
>about popped Alt Field CBs that stay reset? Now
>seems like a temporary intermittent gremlin thats one step ahead of me.
>
>I spent a lot of time during electrical system
>design deciding on Bobs Z13/8 architecture with
>all B&C components. My one data point: works as
>advertised and is more than adequate for
>continued flight after the main alternator goes south.
The main reason that crowbar ov protection is PAIRED
with a crew resetable circuit breaker is to accommodate
the rare but NOT ZERO possibility of a nuisance trip.
In 30 years experience with crowbar ovm in OBAM aircraft
I have heard of perhaps a dozen nuisance trip events, one
of which I helped resolve on a Europa in the shop of
a fellow Beechcrafter. That resolution prompted a design
change based on new knowledge of potential antagonists
to the existing design.
The fact that your breaker stayed in after reset is
a good thing that suggests high probability of a nuisance
trip . . . for reasons that may never be known. Before
you start disassembling the airplane, let's see if the
condition repeats.
The fact that it did not immediately repeat suggests
more of a trip calibration drift than of anything
wrong with the system. It's GOOD to be concerned . . .
it's an abnormal event. But data you have in hand
right now does not ratchet the level of concern up
to the point of crawling over the airplane for hours
chasing the ever elusive electro-snipe . . .
Bob . . .
Message 3
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Subject: | Dimmers driving displays... |
I have a single dimmer that drives my post lights and two new displays (an EI CGR-30P
and a Aerospace Logic fuel gauge. Both units dim nicely with the dimmer,
but during the day when I turn the dimmer off, both devices go to full dim.
Is there a simple circuit that can sense low voltage (below anywhere from 4 to
.5 volts) and switch an output to 12 volts. The panel lights would remain as
connected to the dimmer, the two instruments would be connected via this circuit
allowing them to go to full bright when the dimmer is off.
I anticipate a simple 4 wire device (12V, ground, dimmer in, instrument dimmer
out) and a transistor or two and a couple of resistors...
How are others solving this problem? I am trying to avoid having 17 dimmer controls.
Thoughts?
Andy
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=440189#440189
Message 4
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Subject: | Re: Dimmers driving displays... |
I had a similar issue. I used a simp,e approach. I took a wire off the switched
side of the switch that drove the dimmer and ran that to the coil of a 12v
SPDT relay. The common contact on the relay was connected to the instruments.
The NC contact was connected to 12v power and the NO contact was connected to
the dimmer output. When the dimmer is energized, the instruments lighting circuit
is supplied by the dimmer but when powers removed from the input to the
dimmer, the relay opens and the instruments lighting circuit gets 12v. I did
this for the LCD backlighting of several of my EI instruments.
John Snapp
+1.303.810.0600
( excuse the typos. This email was sent from a mobile device!)
> On Apr 2, 2015, at 6:45 AM, andymeyer <ameyer@mil-amax.com> wrote:
>
>
> I have a single dimmer that drives my post lights and two new displays (an EI
CGR-30P and a Aerospace Logic fuel gauge. Both units dim nicely with the dimmer,
but during the day when I turn the dimmer off, both devices go to full dim.
Is there a simple circuit that can sense low voltage (below anywhere from 4
to .5 volts) and switch an output to 12 volts. The panel lights would remain as
connected to the dimmer, the two instruments would be connected via this circuit
allowing them to go to full bright when the dimmer is off.
>
> I anticipate a simple 4 wire device (12V, ground, dimmer in, instrument dimmer
out) and a transistor or two and a couple of resistors...
>
> How are others solving this problem? I am trying to avoid having 17 dimmer controls.
>
> Thoughts?
>
> Andy
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=440189#440189
>
>
>
>
>
>
>
>
>
>
Message 5
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Subject: | Re: Single fuse for two fuel guages only |
At 13:30 2015-04-01, you wrote:
><recapen@earthlink.net>
>
>I have been doing some rearranging of the wiring and circuit
>protection in my 6A.
>
>I found my two fuel guages ( Vans IE-VFL-15) wired directly to the
>starter power input on the key switch (I must have been lazy that
>day). The documentation calls for 18AWG wiring for this circuit -
>but does not specify circuit protection sizing. I am thinking a 3
>amp fuse should allow sufficient current and provide protection for the wiring.
Your perception is not in error. But why change it?
It's only a venial sin to power multiple appliances
from a single protected tap on the bus. The rule of
thumb calls for evaluating risks to the aircraft or
occupants should ALL appliances un the group become
unavailable due to single fault.
You need to make your own assessment but I suggest
that your time-of-flight is the back-up predictor
of fuel quantity. Given the exceedingly rare event
that ANY protective device will be called upon to
operate over the lifetime of your airplane, it's
an exceedingly low-risk condition to leave it wired
as-is.
Bob . . .
Message 6
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Subject: | Re: Dimmers driving displays... |
At 08:45 2015-04-02, you wrote:
I have a single dimmer that drives my post lights and two new
displays (an EI CGR-30P and a Aerospace Logic fuel gauge. Both units
dim nicely with the dimmer, but during the day when I turn the dimmer
off, both devices go to full dim. Is there a simple circuit that can
sense low voltage (below anywhere from 4 to .5 volts) and switch an
output to 12 volts. The panel lights would remain as connected to the
dimmer, the two instruments would be connected via this circuit
allowing them to go to full bright when the dimmer is off.
I anticipate a simple 4 wire device (12V, ground, dimmer in,
instrument dimmer out) and a transistor or two and a couple of resistors...
How are others solving this problem? I am trying to avoid having 17
dimmer controls.
Thoughts?
The short answer is, yes. I would beg your indulgence
with a suggestion that we make this a thought problem
for the silicon and solder-slingers on the List. How
about it folks? What's the lowest parts count solution
to this design goal . . . hint, there may be more than
one . . .
Bob . . .
Message 7
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Subject: | Re: Single fuse for two fuel guages only |
Bob,
As always, the common-sense of your insight returns me to reality!
Yes, time-of-flight and a fuel-flow meter are also available....
in the event of an in-flight failure.
Additionally, if the circuit had failed 'post-previous-flight',
I would not be able to start the engine for an upcoming flight.
Thanks,
Ralph
-----Original Message-----
>From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
>Sent: Apr 2, 2015 11:28 AM
>To: aeroelectric-list@matronics.com
>Subject: Re: AeroElectric-List: Single fuse for two fuel guages only
>
>
>At 13:30 2015-04-01, you wrote:
>><recapen@earthlink.net>
>>
>>I have been doing some rearranging of the wiring and circuit
>>protection in my 6A.
>>
>>I found my two fuel guages ( Vans IE-VFL-15) wired directly to the
>>starter power input on the key switch (I must have been lazy that
>>day). The documentation calls for 18AWG wiring for this circuit -
>>but does not specify circuit protection sizing. I am thinking a 3
>>amp fuse should allow sufficient current and provide protection for the wiring.
>
> Your perception is not in error. But why change it?
> It's only a venial sin to power multiple appliances
> from a single protected tap on the bus. The rule of
> thumb calls for evaluating risks to the aircraft or
> occupants should ALL appliances un the group become
> unavailable due to single fault.
>
> You need to make your own assessment but I suggest
> that your time-of-flight is the back-up predictor
> of fuel quantity. Given the exceedingly rare event
> that ANY protective device will be called upon to
> operate over the lifetime of your airplane, it's
> an exceedingly low-risk condition to leave it wired
> as-is.
>
>
> Bob . . .
>
>
Message 8
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Subject: | Dimmers driving displays |
>> What's the lowest parts count solution to this design goal
A switch on the back of the dimmer pot... when you go full dim, it switches
bus voltage to the electronic displays.
Can't take credit; Cessna thought of it first! :-)
Paul
Message 9
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Subject: | Re: Dimmers driving displays... |
The same thing can be done by using a DPDT power switch instead of an SPST
switch and relay. Just wire the second pole of the switch to do the same
thing your SPDT relay is doing. The center contact goes to the devices
that should be bright when the lights are off. The "on" side goes to the
dimmer output, and the "off" side goes to the dimmer power input.
Gerald
On Thu, Apr 2, 2015 at 10:24 AM, john Snapp <matronics.list@gmail.com>
wrote:
> matronics.list@gmail.com>
>
> I had a similar issue. I used a simp,e approach. I took a wire off the
> switched side of the switch that drove the dimmer and ran that to the coil
> of a 12v SPDT relay. The common contact on the relay was connected to the
> instruments. The NC contact was connected to 12v power and the NO contact
> was connected to the dimmer output. When the dimmer is energized, the
> instruments lighting circuit is supplied by the dimmer but when powers
> removed from the input to the dimmer, the relay opens and the instruments
> lighting circuit gets 12v. I did this for the LCD backlighting of several
> of my EI instruments.
>
> John Snapp
>
> +1.303.810.0600
> ( excuse the typos. This email was sent from a mobile device!)
>
> > On Apr 2, 2015, at 6:45 AM, andymeyer <ameyer@mil-amax.com> wrote:
> >
> ameyer@mil-amax.com>
> >
> > I have a single dimmer that drives my post lights and two new displays
> (an EI CGR-30P and a Aerospace Logic fuel gauge. Both units dim nicely with
> the dimmer, but during the day when I turn the dimmer off, both devices go
> to full dim. Is there a simple circuit that can sense low voltage (below
> anywhere from 4 to .5 volts) and switch an output to 12 volts. The panel
> lights would remain as connected to the dimmer, the two instruments would
> be connected via this circuit allowing them to go to full bright when the
> dimmer is off.
> >
> > I anticipate a simple 4 wire device (12V, ground, dimmer in, instrument
> dimmer out) and a transistor or two and a couple of resistors...
> >
> > How are others solving this problem? I am trying to avoid having 17
> dimmer controls.
> >
> > Thoughts?
> >
> > Andy
> >
> >
> >
> >
> > Read this topic online here:
> >
> > http://forums.matronics.com/viewtopic.php?p=440189#440189
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
>
>
Message 10
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Subject: | Re: Dimmers driving displays... |
No switched side of that dimmer knob... It's simply a pot - it may go open when
all of the way dim - not sure... I'd rather not change out the pot - something
simple and inline to the two instruments would be ideal. I thought about a low
pull-in voltage relay, but pull-in would have to be at a couple of volts and
very low current and rated for continuous duty at 14 volts, and still very low
current.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=440206#440206
Message 11
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Subject: | Re: Dimmers driving displays... |
Is there a significant issue with running your panel lights during the day?
Daniel Hooper
> On Apr 2, 2015, at 12:55 PM, andymeyer <ameyer@mil-amax.com> wrote:
>
>
> No switched side of that dimmer knob... It's simply a pot - it may go open when
all of the way dim - not sure... I'd rather not change out the pot - something
simple and inline to the two instruments would be ideal. I thought about a
low pull-in voltage relay, but pull-in would have to be at a couple of volts
and very low current and rated for continuous duty at 14 volts, and still very
low current.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=440206#440206
>
>
>
>
>
>
>
>
>
>
Message 12
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Subject: | Re:_AeroElectric-List:_Re:_Dimmers_driving_displays...? |
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DQpSb2dlcg=
Message 13
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Subject: | Re: BMA Powerboard with Z19RB |
>>Eagerly looking forward to words of wisdom from this enlightened group.
>
> You've already been offered some such words . . . I'm packing
> up for a day-trip to Wichita to visit a customer but I'll
> be back this evening to address your questions in more detail.
> In the mean time there are no doubt others who would like
> to share ideas and reasons . . .
BMA has a rich history in amateur built aviation that
offers many reasons to ponder the wisdom of going
airborne with any of their products.
As much as I gunch and groan about the floobydust
and hoop-jumping forced upon TC aviation, there are
fundamentals that go to design, verification and system
reliability that have nothing to do with regulations.
They have everything to do with simple ideas in physics
and reduction in risk by capitalizing on lessons learned
and putting lots of clear heads onto good critical
review.
In spite of offers from myself and others for free
assists in such matters, the BMA design and marketing
philosophy plodded on to a predictable outcome. Perhaps
good fortune smiled down on OBAM aviation with
respect to BMA. I'm aware of no instances of injury
or damage to an aircraft due to failure of BMA
products to perform. At the same time, I'm equally
unaware of any pilot who claims to trust his BMA
fitted airplane enough to go bore precision holes in clouds.
You can read my best efforts to engage Mr. Richter
in the simple ideas and proven practices for wiring
an airplane here . . .
http://tinyurl.com/omnuypr
I had no opportunity to engage him in conversation
about software performance and robustness testing,
failure mode effects analysis or partitioning
functionality for independence, much less fabrication
for survival in the aviation environment. Based on
what I learned in the exchange above . . . well . . .
It's your choice my friend but I would look long
and hard for any success stories about the hardware
you are contemplating for your airplane.
Personally, I'd rather launch into clouds with
needle, ball, airspeed, hand held gps and a wing
leveler (or two) than with the BMA suite of
products.
Bob . . .
Message 14
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Subject: | Re: Dimmers driving displays |
At 10:57 2015-04-02, you wrote:
>
> >> What's the lowest parts count solution to this design goal
>
>A switch on the back of the dimmer pot... when you go full dim, it switches
>bus voltage to the electronic displays.
>
>Can't take credit; Cessna thought of it first!
Ahhh . . . that recalls the switch on the
back of the dimmer pot in some Pipers
that automatically turned on position lights
when the panel lights were brought up.
Nice take. The switchs at the CCW end of
pots tend to go open at max travel, so
you still have to add some electro-beans
to invert the sense.
Bob . . .
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