Today's Message Index:
----------------------
1. 07:32 AM - Re: Re: Fusible links (Christopher Cee Stone)
2. 07:49 AM - Re: Plane Power alternator $$$$ (Coastflyer)
3. 08:00 AM - Re: Re: Fusible links (Robert L. Nuckolls, III)
4. 08:18 AM - Z-14 !!!!NOT!!!! Z-12 times TWO is the appropriate foundation (Robert L. Nuckolls, III)
5. 08:24 AM - Re: Re: Plane Power alternator $$$$ (Robert L. Nuckolls, III)
6. 08:28 AM - Re: Re: Fusible links (Christopher Cee Stone)
7. 08:29 AM - Re: Re- Activation of account, Matronics Email Lists Forums - "esco" (Robert L. Nuckolls, III)
8. 08:30 AM - Re: Re: Non-aircraft question (OK, maybe a plane with a galley) (Dave Saylor)
9. 08:46 AM - Re: Re: Fusible links (Charlie England)
10. 09:24 AM - Re: Re: Fusible links (Robert L. Nuckolls, III)
11. 10:06 AM - Re: Re: Fusible links (Christopher Cee Stone)
Message 1
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| Subject: | Re: Fusible links |
Back to the original question of the length of a fusible link. That is the
length of smaller gauge wire comprising the 'link'.
The premise being that a dead short of the fusible link protected wire
would see the full system power supplied by, battery and/or alternator
sources. Thus the 'link' would see in the case of the battery maybe 200
amps. In the case of alternator alone (assuming battery failure) 60 amps.
Thus a 24 awg link would fail pretty quickly as the heating would be (and
I'm taking a swag here) instantaneous or at most 2- 3 seconds to burn
through. If the 'link' were 2" rather than 6" some head would be conducted
into the connecting conductor which is 18 awg with PIDG splices. But the
'link' would still fail. As it is encased in a fibreglass sleeve, no harm
other than the smell of burnt tefzel.
The specific application here are the E-mag power wires which
e-magair specs call for 18 awg. One from the battery bus and one from the
primary bus.
Pending the conclusions of this paper study I will go to the bench and
test. I have created electrical systems for a number of aircraft using 2"
fusible links. If there is a problem with this length I will recall my
work and make the necessary revisions.
...chris
RV's and Kitfoxes
On Fri, Dec 22, 2023 at 3:19=AFPM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 11:29 AM 12/22/2023, you wrote:
>
>
> Hi All;
> I know this is going to create controversy, but I think fusible links are
> a crutch, and an unreliable one at that. Why utilize fusible links, when
> fuses themselves, are so inexpensive, more predictable, and easier to
> diagnose and change? If you look at modern automobile production, you won
't
> find a single fusible link, but dozens of cheap, compact, and reliable
> automobile-type fuses.
> Cheers!
>
>
> A fusible link is not a 'fuse'. It's not as finely
> calibrated as fuses. It's in the same class of
> fault protection as a ANL current limiter. See:
>
> * https://tinyurl.com/k7o3l3q <https://tinyurl.com/k7o3l3q>*
>
> Note a 100A version of this device will carry
> 200A for about 12 seconds! This is typical
> of all such devices in this class of protection.
> Automobiles have been fitted with fusible links
> as specially insulated WIRE for decades. The
> auto parts stores carry replacement links . . .
> not rated in amps but in AWG wire size. Modern
> cars have migrated to miniature 'cartridge'
> limiters such as the MIDI series from Littlefuse:
>
> http://tinyurl.com/4av7s3ya
>
> Note that a MIDI30 is rated to carry 200A
> for 200mS; 60A for 8S and 40A for essentially
> forever.
>
> The purpose and application for such devices
> is to protect extended BUS STRUCTURES from
> battery excited, HARD FAULTS generally expected
> to be many times the device's 'rating'.
>
> This is why you do not see them sprinkled about
> the Z-figures. I use them to extend a bus to
> the crowbar circuit breaker, protect the alternator
> B-lead from shorts in the diode array, protect
> the feeder to an auxiliary bus which will support
> fuses and or breakers to individual appliances.
>
> Fusible link technology is widely exploited
> in DC power systems of all stripes. Pre-assembled
> fusible links as well as bulk wire (special
> insulation) are offered by the likes of Mouser,
> eBay, Amazon, virtually ALL auto parts stores,
> etc.
>
> * https://tinyurl.com/yllq8uym <https://tinyurl.com/yllq8uym>*
>
> Don't conflate the words 'fuse' and 'fusible'.
> Fuses are fusible but fusible links are not
> fuses. I prefer them to ANL/MIDI solutions
> for their simplicity . . . a piece of
> specially insulated wire will mitigate
> and contain the energies of a fusing event.
> Can't beat them for cost, size, weight, labor,
> etc.
>
> But don't use them where a circuit breaker
> or fuse is called for . . . that's a
> different task altogether.
>
> 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 2
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| Subject: | Re: Plane Power alternator $$$$ |
So I installed the new PP alternator and test flew it yesterday.
The alternator load seems to fluctuate more than I remember with the old one.
For example with all avionics and external lights on, the load fluctuates between
approximately 14-17 amps.
This fluctuation doesnt seem normal, at least compared to my old alternator.
Maybe there has been a change to the regulator in the last 12 years, or maybe my
belt is slipping a bit? Any advice?
Thanks
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=512930#512930
Message 3
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| Subject: | Re: Fusible links |
At 09:31 AM 12/23/2023, you wrote:
>Back to the original question of the length of a
>fusible link. That is the length of smaller gauge wire comprising=C2 the
'link'.
Had to do some 'digging' to see if I could
find where that 3-6 inch citation came from.
No joy.
Actually, 6" is the minimum. 9" is more typical,
10" not unheard of. 3" is too short . . .
. . . and INSULATED with material resistant to
energy released by clearing the fault.
See: http://tinyurl.com/4vnzdjpc
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 4
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| Subject: | Z-14 !!!!NOT!!!! Z-12 times TWO is the appropriate |
foundation
At 08:16 PM 12/22/2023, you wrote:
>>How would one incorporate the second engine starting system
>>into the Z-14 diagram? The alternators will be one 40 amp per
>>engine. Is there anyone who can help with this?
>
> Z14 illustrates TWO, independently
> energized electrical systems . . .whether
> driven by two alternators on one engine or
> two alternators on two engines.
The attached cartoon illustrates a side-by-side, single
engine systems with two alternators and one battery.
No interchange of energy between the two after cranking
and in normal ops.
A cross-feed contactor allows exchange of energy between
the systems during (1) cranking and (2) aid to a
compromised system by the system not compromised.
Ignore details of the drawing speaking to brands and
styles of hardware. Focus on architecture to decide
how the system would be operated during predicted
failures.
This seems to be the simplest way to achieve the
greatest flight system reliability for the
engine/accessory combination under discussion.
At the moment I perceive no need for separate engine
busses or considering any form of battery-only
operations. Need for such features implies a
risk of MULTIPLE failures that cannot be mitigated
by the architecture illustrated.
Simple, straightforward legacy operation/risk
for both systems.
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: Plane Power alternator $$$$ |
At 09:49 AM 12/23/2023, you wrote:
<jessejenks72@gmail.com>
>
>So I installed the new PP alternator and test flew it yesterday.
>The alternator load seems to fluctuate more than
>I remember with the old one. For example with
>all avionics and external lights on, the load
>fluctuates between approximately 14-17 amps.
>This fluctuation doesn=99t seem normal, at least
>compared to my old alternator.
>Maybe there has been a change to the regulator
>in the last 12 years, or maybe my belt is slipping a bit? Any advice?
Alternator CURRENT cannot truly change without
a variation in LOAD presented by the system -OR-
a similar fluctuation in bus voltage. What's
the bus voltage doing? Suggest you check it with
more than one instrument. Jumpy readings in 1970
were cause for concern before digital instrumentation.
Nowadays, you question/verify the instrumentation
first.
If the regulator is bad, bus voltage will be
similarly 'jumpy' but in very small excursions.
It might require close examination of bus voltage
with an analog voltmeter (small with a short pointer)
to see if the voltage is unstable. Do this
before getting out the hammers-n-saws.
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: | Re: Fusible links |
The Delphi spec does not indicate length. Really is' material properties
not performance characteristics.
I will do a couple of tests with varying "link" lengths using a fully
charged 12v, group 24, new lead acid battery. (I happen to have a new one
in the shop)
Unfortunately I don't have a recording scope at the moment... so this will
have to be an empirical test. That is, what is the failure mode, not time
to 'link' open.
Test specimens: 24 awg tefzel wire 'links', connected to 18 awg feeder
using PIDG butt splices, fibreglass sleeve.
'link' lengths in inches: 2,3,6,12
Comments/suggestions are welcomed!
I will post results in the coming days.
...chris
On Sat, Dec 23, 2023 at 8:02=AFAM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 09:31 AM 12/23/2023, you wrote:
>
> Back to the original question of the length of a fusible link. That is th
e
> length of smaller gauge wire comprising=C3=82 the 'link'.
>
>
> Had to do some 'digging' to see if I could
> find where that 3-6 inch citation came from.
> No joy.
>
> Actually, 6" is the minimum. 9" is more typical,
> 10" not unheard of. 3" is too short . . .
>
> . . . and INSULATED with material resistant to
> energy released by clearing the fault.
>
> See: http://tinyurl.com/4vnzdjpc
>
>
> 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 7
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| Subject: | Re: Re- Activation of account, Matronics Email Lists |
Forums - "esco"
At 09:19 PM 12/22/2023, you wrote:
>Aeroelectric List Moderator:=C2 request re-activation of my account.=C2
>It worked for a few days -maybe a week?- and now I can't log in, again.
I've requested de-activation of your
account on the public www.matronics.com/subscribe
page. I will attempt to re-activate it later today
whereupon you will receive a second email addressing
the action.
I PRESUME you're able to read this message on the
browser-based portal to the List . . . if not, then
I'm hollering down a rabbit hole.
Not sure why the message spoke to the 'moderator' as
having control of this function. Not true. There's
nothing I can do that you cannot do on the subscription
page cited above.
Matt is the technowienie who drives this activity.
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 8
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| Subject: | Re: Non-aircraft question (OK, maybe a plane with |
a galley)
My microwave is working now. I replaced the large capacitor, but it kept
blowing the fuse. After some research I removed the bidirectional diode
and now it works normally.
I learned that testing a large diode with my DMM isn't possible, even on
the diode/beep scale. I had to put a small current through it with a bench
power supply to see any of the diodes in action. And I learned that
there's such a thing as a bidirectional diode.
This troubleshooting took awhile because Amazon sold me a part number that
should be a bidirectional diode but it wasn't. Glad I didn't have to do a
flight test on this one. Just hot coffee.
--Dave
On Thu, Dec 21, 2023 at 6:10=AFPM Dave Saylor <saylor.dave@gmail.com>
wrote:
> Thanks Joe. The door switches are good, still looking.
>
> On Thu, Dec 21, 2023 at 13:21 user9253 <fransew@gmail.com> wrote:
>
>>
>> I had the same problem with my microwave. The problem was the door
>> switch. Evidently the microwave was designed so that if it operates wit
h
>> the
>> door not fully latched, then it will short out the power supply. How
>> dare them
>> design something that blows the house circuit breaker which could cause
>> the
>> refrigerator to quit and spoil food. I bypassed that switch. The
>> microwave
>> has been working fine for years since.
>>
>> --------
>> Joe Gores
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/viewtopic.php?p=512829#512829
>>
>>
>>
>>
>>
>>
===========
===========
===========
===========
===========
>>
>>
>>
>>
Message 9
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| Subject: | Re: Fusible links |
Only thought is that the normal 'spread' is 4; not 6. 22 for 18, 20 for 16,
etc. OTOH, testing might show that if using a really short link, using a
wider spread might be helpful, because the shorter length is going to
reduce system heating.
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_c
ampaign=sig-email&utm_content=webmail>
Virus-free.www.avast.com
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ampaign=sig-email&utm_content=webmail>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
On Sat, Dec 23, 2023 at 10:30=AFAM Christopher Cee Stone <rv8iator@gm
ail.com>
wrote:
> The Delphi spec does not indicate length. Really is' material properties
> not performance characteristics.
>
> I will do a couple of tests with varying "link" lengths using a fully
> charged 12v, group 24, new lead acid battery. (I happen to have a new one
> in the shop)
>
> Unfortunately I don't have a recording scope at the moment... so this wil
l
> have to be an empirical test. That is, what is the failure mode, not tim
e
> to 'link' open.
>
> Test specimens: 24 awg tefzel wire 'links', connected to 18 awg feeder
> using PIDG butt splices, fibreglass sleeve.
>
> 'link' lengths in inches: 2,3,6,12
>
> Comments/suggestions are welcomed!
>
> I will post results in the coming days.
>
> ...chris
>
>
> On Sat, Dec 23, 2023 at 8:02=AFAM Robert L. Nuckolls, III <
> nuckolls.bob@aeroelectric.com> wrote:
>
>> At 09:31 AM 12/23/2023, you wrote:
>>
>> Back to the original question of the length of a fusible link. That is
>> the length of smaller gauge wire comprising=C3=82 the 'link'.
>>
>>
>>
>> Had to do some 'digging' to see if I could
>> find where that 3-6 inch citation came from.
>> No joy.
>>
>> Actually, 6" is the minimum. 9" is more typical,
>> 10" not unheard of. 3" is too short . . .
>>
>> . . . and INSULATED with material resistant to
>> energy released by clearing the fault.
>>
>> See: http://tinyurl.com/4vnzdjpc
>>
>>
>>
>>
>> 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 10
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| Subject: | Re: Fusible links |
At 10:27 AM 12/23/2023, you wrote:
>The Delphi spec does not indicate
>length.=C2 Really=C2 is' material properties not performance
characteristics.
There were TWO data points in that link . . .
One was a listing of manufactured links specific to
certain automotive applications:
https://tinyurl.com/yrgvc2er
Here we see lengths quoted from 8" to 10.5"
I've read other sources citing similar
lengths. Too short compromises the fusing
dynamic of which material properties a
part of the formula.
>I will do a couple of tests with varying "link"
>lengths using a fully charged 12v, group 24, new
>lead acid battery. (I happen to have a new one in the shop)
>Unfortunately I don't have a recording scope at
>the moment... so this will have to be an
>empirical=C2 test.=C2 That is, what is the failure mode, not time to
'link' open.
>
>Test specimens: 24 awg tefzel wire 'links',
>connected to 18 awg feeder using PIDG butt splices,=C2 fibreglass sleeve.
>
>'link' lengths=C2 in inches: 2,3,6,12
24AWG links are atypical of the devices in
common use. That combination of fiberglas over
24AWG was crafted in our shops about 30 years
ago as an alternative to cartridge fuses in the
leads between an b-lead shunt and a panel-ammeter.
I have no doubt that you will successfully 'fuse'
2" lengths of 24AWG . . . 100+ amps of battery
current pretty well predicts the outcome.
When I'm considering a 'bus extension' in
crafting an architecture, the decision considers
mechanical robustness and ease of reliable assembly.
For example, extending the bus out to a 5A crowbar
breaker might call for 20AWG fusible link driving
a 16AWG extension.
These are system segments NOT part of the
post crash fire safety considerations that call
for relatively small, FAST protection on always
hot circuits. 7A fuses work good in crash post
crash fire concerns.
Hence my design decision would lean toward easily
acquired, manufactured link material that behaves
well in PIDG crimps . . . there is no practical
motivation to consider 'amperage' values for
the links.
But having offered that, I'm interested in results
of your experiments. You can roughly control
the magnitude of fault current by how much 20AWG
wire is in series with your link. I'd shoot for
something on the order of 100A. 20AWG is 10mOHMs/foot.
Your battery will present a series impedance on the order
of 10 mOhm. So 5 feet of wire in the remainders of
the test loop would be about right.
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 11
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| Subject: | Re: Fusible links |
...appreciate your discussion and input!
This discussion is the result of the addition of two E-mags to the current
RV project and reviewing the Emag installation instruction. They call for a
circuit breaker in series with the power feeder for the E-mag(s). I am
using Z-13/8 as a reference guide for this build. I am considering a
fusible link instead of a circuit breaker as I am running out of panel
space. Thus my concern for both reliability and safety.
...chris
On Sat, Dec 23, 2023 at 9:26=AFAM Robert L. Nuckolls, III <
nuckolls.bob@aeroelectric.com> wrote:
> At 10:27 AM 12/23/2023, you wrote:
>
> The Delphi spec does not indicate length.=C3=82 Really=C3=82 is' materia
l
> properties not performance characteristics.
>
>
> There were TWO data points in that link . . .
>
> One was a listing of manufactured links specific to
> certain automotive applications:
>
> * https://tinyurl.com/yrgvc2er <https://tinyurl.com/yrgvc2er>*
>
> Here we see lengths quoted from 8" to 10.5"
> I've read other sources citing similar
> lengths. Too short compromises the fusing
> dynamic of which material properties a
> part of the formula.
>
>
> I will do a couple of tests with varying "link" lengths using a fully
> charged 12v, group 24, new lead acid battery. (I happen to have a new one
> in the shop)
> Unfortunately I don't have a recording scope at the moment... so this wil
l
> have to be an empirical=C3=82 test.=C3=82 That is, what is the failure m
ode, not
> time to 'link' open.
>
> Test specimens: 24 awg tefzel wire 'links', connected to 18 awg feeder
> using PIDG butt splices,=C3=82 fibreglass sleeve.
>
> 'link' lengths=C3=82 in inches: 2,3,6,12
>
>
> 24AWG links are atypical of the devices in
> common use. That combination of fiberglas over
> 24AWG was crafted in our shops about 30 years
> ago as an alternative to cartridge fuses in the
> leads between an b-lead shunt and a panel-ammeter.
>
> I have no doubt that you will successfully 'fuse'
> 2" lengths of 24AWG . . . 100+ amps of battery
> current pretty well predicts the outcome.
>
> When I'm considering a 'bus extension' in
> crafting an architecture, the decision considers
> mechanical robustness and ease of reliable assembly.
> For example, extending the bus out to a 5A crowbar
> breaker might call for 20AWG fusible link driving
> a 16AWG extension.
>
> These are system segments NOT part of the
> post crash fire safety considerations that call
> for relatively small, FAST protection on always
> hot circuits. 7A fuses work good in crash post
> crash fire concerns.
>
> Hence my design decision would lean toward easily
> acquired, manufactured link material that behaves
> well in PIDG crimps . . . there is no practical
> motivation to consider 'amperage' values for
> the links.
>
> But having offered that, I'm interested in results
> of your experiments. You can roughly control
> the magnitude of fault current by how much 20AWG
> wire is in series with your link. I'd shoot for
> something on the order of 100A. 20AWG is 10mOHMs/foot.
> Your battery will present a series impedance on the order
> of 10 mOhm. So 5 feet of wire in the remainders of
> the test loop would be about right.
>
>
> 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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