Today's Message Index:
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0. 02:27 PM - Coming Soon - The List of Contributors - Please Make A Contribution Today! (Matt Dralle)
1. 06:01 AM - Re: Power, signal, and Coax - How should they be bundled? (wsimpso1)
2. 06:29 AM - Re: Re: Power, signal, and Coax - How should they be bundled? (Charlie England)
3. 11:05 AM - Re: Fuse Upstream of Breaker (Jeff Luckey)
4. 12:03 PM - Re: OVM-14 MkIII development program (Terry Menees)
5. 12:18 PM - Re: OVM-14 MkIII development program (Terry Menees)
6. 02:15 PM - Ray Allen servo cable (John Bright)
7. 03:32 PM - Re: Fuse Upstream of Breaker (Charlie England)
8. 04:00 PM - Re: Fuse Upstream of Breaker (Robert L. Nuckolls, III)
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| Subject: | Coming Soon - The List of Contributors - Please Make |
A Contribution Today!
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Message 1
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| Subject: | Re: Power, signal, and Coax - How should they be bundled? |
Thanks for the knowledgeable responses.
It looks like nothing I have in the back end is terribly sensitive, and the thinking
around the topic is mostly fuss over nothing. So, in the aft end of the
fuselage, it is looking like this:
Starboard side will get all three antenna cables, 3 sets of 3 sense wires from
the trim motors, and both the three wire shielded cable and RJ11 for the ELT;
Port side will get 3 pairs of trim motor power wires, and the shielded two wire
LED power cable.
Further forward is more up in the air, but it is looking like we will add fat wires
and any noisy stuff on port side while starboard will get data, DYNON system
cable, etc. Centerline is already tied up with flight controls, fuel lines,
and air handling.
It is also looking like I will be making twisted pairs for the trim motor power
and twisted triplets for trim sensing, This more for neatness and keeping things
straight than for noise control. Onward to system numbering etc.
Thanks again.
Billski
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=512317#512317
Message 2
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| Subject: | Re: Power, signal, and Coax - How should they |
be bundled?
Are you using the Ray Allen trim servos? If so, it's worth noting that
there are thousands of them flying with power & signal wires bundled in
the same cable, as spec'd & sold by the company. From the installation
guide:
[image: image.png]
On Fri, Nov 17, 2023 at 8:05=AFAM wsimpso1 <wsimpso1@comcast.net> wro
te:
>
>
> Thanks for the knowledgeable responses.
>
> It looks like nothing I have in the back end is terribly sensitive, and
> the thinking around the topic is mostly fuss over nothing. So, in the aft
> end of the fuselage, it is looking like this:
>
> Starboard side will get all three antenna cables, 3 sets of 3 sense wires
> from the trim motors, and both the three wire shielded cable and RJ11 for
> the ELT;
> Port side will get 3 pairs of trim motor power wires, and the shielded tw
o
> wire LED power cable.
>
> Further forward is more up in the air, but it is looking like we will add
> fat wires and any noisy stuff on port side while starboard will get data,
> DYNON system cable, etc. Centerline is already tied up with flight
> controls, fuel lines, and air handling.
>
> It is also looking like I will be making twisted pairs for the trim motor
> power and twisted triplets for trim sensing, This more for neatness and
> keeping things straight than for noise control. Onward to system numberin
g
> etc.
>
> Thanks again.
>
> Billski
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=512317#512317
>
>
===========
===========
===========
===========
===========
>
>
Message 3
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| Subject: | Re: Fuse Upstream of Breaker |
Re Bob's Accident Analysis:I stand corrected.=C2- My recollection was a
little faulty. (no big surprise)
This case is fascinating to me.=C2- It appears to be a classic case of "o
ver-engineering".=C2- The designer(s) were trying to be uber-redundant an
d in so doing they, shall we say, "screwed the pooch".=C2- I'm glad to be
reminded that it was not fatal.
Please understand that my intent is not to criticize the people involved bu
t to learn how not to make the same mistake.=C2- (And I have to say, kudo
s to BobN for fostering and promoting that philosophy here on the List)
So Bob, after watching some of your videos, I don't recall what size fuse w
as used in the upstream position.=C2- Was it 5A, same as the breakers?
Experiments from "The Lab":
I did some experimentation and found that a fuse upstream of a breaker need
s to be at least 4x the breaker rating.=C2- I put a 30A fuse upstream fro
m a 5A breaker and the fuse held, and the breaker popped.=C2- (yes, that
is 6x, but I didn't have any 20A fuses).=C2- I performed the test at leas
t 10 times.
Also tested with 10A breaker.=C2- First, with a 30A fuse which blew insta
ntly.=C2- Then with a 40A fuse which held and the 10A breaker popped, aga
in 10 cycles.=C2- (hence the 4x)
Sometimes I would have to wait 10 to 30 seconds before the breaker would re
set.=C2- Ambient temp was 68F.
My setup:I was using a freshly-charged PC-680, about 3 feet of 18 AWG wire,
a mil-spec SPST toggle switch (cuz that's what I had lying around), ATO au
tomotive fuses and connecting to them using individual .250 tab connectors.
Observational Note:I was surprised at how big the "pop" was in the 30A fuse
when testing the 10A breaker.=C2- There was a clearly audible "snap" or
"pop" and a bright flash as the fuse element burned.=C2- I thought it wou
ld just quietly melt.=C2- The circuit breakers were: 10A WX23 series (pus
h-pull) and a WX58 5A (push to reset).
I like the fuse for this because:1. It just uses a regular slot in the fuse
block2. It uses a stock, cheap fuse3. It's easy to replace
4. There are no lengths of #22 being vaporized at high temps5. The fuse ele
ment is encapsulated in an enclosure that is designed to contain its melt-d
own. (you know, It's a fuse;)
People have suggested that the "recommended" solution for this scenario is
a fusible link.=C2- Why is a fusible link better than a 4x fuse under the
se relatively low-current situations?
Inquiring minds....
-Jeff
On Tuesday, November 14, 2023 at 01:15:32 PM PST, Robert L. Nuckolls, I
II <nuckolls.bob@aeroelectric.com> wrote:
=C2- The mainfuse went first leaving the aux fuse
=C2- to soldier on for some number of flight cycles
=C2- but it too eventually succumbed to the
=C2- abuse.
=C2-=C2- This is what FMEA is all about. Here was an
=C2-=C2- opportunity for a latent failure to go
=C2-=C2- un-annunciated and impossible to
=C2-=C2- detect in a pre-flight procedure. Interestingly
=C2-=C2- also, even if the fuses had been fitted with
=C2-=C2- LED indicators, it is unlikely that the
=C2-=C2- failed fuse would have 'indicated' anything.
=C2-=C2- Voltage across open fuse too low.
=C2- Bob . . .
=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2
-=C2-=C2-=C2-=C2-=C2-////
=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2
-=C2-=C2-=C2-=C2-(o o)
=C2-=C2- ===========o00o=(_)=o00o====
=====
=C2-=C2- < Go ahead, make my day . . .=C2-=C2- >
=C2-=C2- < show me where I'm wrong.=C2-=C2-=C2-=C2-=C2->
=C2-=C2- ====================
============
=C2-
=C2-=C2- In the interest of creative evolution
=C2-=C2- of the-best-we-know-how-to-do based
=C2-=C2- on physics and good practice.
Message 4
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| Subject: | Re: OVM-14 MkIII development program |
I'd be happy to try it out in a couple of months for the Revmaster
installation in my Cygnet project.
Looking forward to seeing how it works.
Terry
On Thu, Nov 16, 2023 at 8:13=AFPM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 06:55 PM 11/16/2023, you wrote:
>
> Bob,
> If you are looking for field testers let me know (I have an RV6 with auto
> alternator, external regulator, and AGM battery - and no OVP - eeek!). I
> can certainly install and test it, but have no surface mount experience,
so
> assembly is probably a bridge too far.
>
>
> Thank you for the offer! You're on the list for
> first article. As soon as I'm satisfied with the
> performance, I'll be looking for some 'victims'
> willing to add their experience/observations
> to the development of this product.
>
>
> Bob . . .
>
> ////
> (o o)
> ===========o00o=(_)=o00o======
==
> < Go ahead, make my day . . . >
> < show me where I'm wrong. >
> =======================
=========
>
> In the interest of creative evolution
> of the-best-we-know-how-to-do based
> on physics and good practice.
>
Message 5
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| Subject: | Re: OVM-14 MkIII development program |
I'd be happy to try it out in a couple of months for the Revmaster
installation in my Cygnet project.
Looking forward to seeing how it works.
Terry
________________________________
From: owner-aeroelectric-list-server@matronics.com <owner-aeroelectric-list
-server@matronics.com> on behalf of Robert L. Nuckolls, III <nuckolls.bob@a
eroelectric.com>
Sent: Thursday, November 16, 2023 8:04 PM
Subject: Re: AeroElectric-List: OVM-14 MkIII development program
At 06:55 PM 11/16/2023, you wrote:
Bob,
If you are looking for field testers let me know (I have an RV6 with auto a
lternator, external regulator, and AGM battery - and no OVP - eeek!). I ca
n certainly install and test it, but have no surface mount experience, so a
ssembly is probably a bridge too far.
Thank you for the offer! You're on the list for
first article. As soon as I'm satisfied with the
performance, I'll be looking for some 'victims'
willing to add their experience/observations
to the development of this product.
Bob . . .
////
(o o)
===========o00o=(_)=o00o=======
=
< Go ahead, make my day . . . >
< show me where I'm wrong. >
========================
========
In the interest of creative evolution
of the-best-we-know-how-to-do based
on physics and good practice.
Message 6
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| Subject: | Ray Allen servo cable |
Someone pointed out Ray Allen sells five-conductor cable for servo installa
tion... it's 24 awg and Teflon insulated. FYI Stein has five-conductor cabl
e in Ray Allen colors, 22 awg Tefzel insulated, Stein PN AWG22-5, same pric
e as the Ray Allen cable.
Message 7
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| Subject: | Re: Fuse Upstream of Breaker |
snipped
>
>
> People have suggested that the "recommended" solution for this
> scenario is a fusible link. Why is a fusible link better than a 4x
> fuse under these relatively low-current situations?
>
>
> Inquiring minds....
>
>
> -Jeff
>
>
I like them because once they're fab'd, they're zero maintenance and
virtually zero risk of failure/nuisance trip, and there are fewer
failure points because there are fewer joints in the path. Any fault
severe enough to 'trip' the link is going to make a far larger arc, and
noise, and smoke puff, than the link itself will make. It's simple and
cheap to test; that's what I did to verify the safety/effectiveness of
using silicone tubing for the protective layer over the link.
--
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Message 8
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| Subject: | Re: Fuse Upstream of Breaker |
At 05:36 PM 11/17/2023, you wrote:
>snipped
>>
>>
>>
>>People have suggested that the "recommended" solution for this
>>scenario is a fusible link.=C2 Why is a fusible
>>link better than a 4x fuse under these relatively low-current situations?
The fusible link is close cousin to the
ANL/MANL/MIDI current limiters. Much more
robust than a fuse but STILL quite capable
of protecting a feeder suffering a hard-fault.
That short chunk of wire from main bus to
the alternator field crowbar breaker is
an EXTENSION of the main bus. Protection
on a bus extension is tailored to protect
the conductor but expected to source one
or more, smaller feeders for ship's
accessories. The I(squared)T value for
the link is several times larger than
any downstream breaker/fuse.
Some of my builders have used this extension
to source a crowbar field breaker -and- supply
breaker to the autopilot. This was to provide
a means for disabling the a/p should it become
fussy. One might find it useful to source other
breakers in an otherwise all-fuse airplane. In
this case, the extension might be upsized to
12AWG with a 16AWG fusible link.
It's a reliable, simpler, low parts count way
to extend the bus without 'wasting' a slot in your
fuseholder.
Bob . . .
////
(o o)
===========o00o=(_)=o00o=======
=
< Go ahead, make my day . . . >
< show me where I'm wrong. >
========================
========
In the interest of creative evolution
of the-best-we-know-how-to-do based
on physics and good practice.
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