Today's Message Index:
----------------------
1. 03:03 AM - Endurance bus switch (John Keen)
2. 05:53 AM - Re: Endurance bus switch (user9253)
3. 07:04 AM - Is there M39029/63-3XX For 18 AWG Wire?!?!? (William Hunter)
4. 07:21 AM - Re: *** SPAM *** Is there M39029/63-3XX For 18 AWG Wire?!?!? (Tim Olson)
5. 07:41 AM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (user9253)
6. 08:07 AM - Re: Endurance bus switch (Robert L. Nuckolls, III)
7. 08:13 AM - Re: Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (Robert L. Nuckolls, III)
8. 08:22 AM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (Charlie England)
9. 08:52 AM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (Art Zemon)
10. 09:17 AM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (Robert L. Nuckolls, III)
11. 09:52 AM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (William Hunter)
12. 11:36 AM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (Robert L. Nuckolls, III)
13. 11:57 AM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (William Hunter)
14. 05:52 PM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (Robert L. Nuckolls, III)
15. 06:02 PM - Re: Re: Today's trivia dump . . . (Eric Page)
16. 07:29 PM - Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? (William Hunter)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Endurance bus switch |
Hi Bob,
I=99m building an RV-7 and tackling the wiring, thank you for
sharing the invaluable knowledge in your book.
I=99ve been grappling with whether or not to wire the endurance
bus directly through the switch or use a relay. The switch is rated at
20 amps but the bus could conceivably see up to 24 amps if everything on
the bus was on and drawing its maximum, eg radio transmitting,
transponder transponding and GPS charging for example.
Regards,
John.
John Keen
0412 141 833
15 Scott St
Scone NSW Australia 2337
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Endurance bus switch |
The deciding factor is not ampacity because either a relay or a switch will work.
Even if a switch is operated above its rating, it will not immediately self
destruct. For example, if a 20 amp switch carries 24 amps, it might only last
50,000 cycles instead of its 100,000 cycle life expectancy. It could still
outlive the life of the aircraft.
The important consideration is remote control. Locating a relay close to the
battery allows power to be shut off close to the source. A small switch and
small wires can be used to control the relay. A government accident investigator
once made the comment that the chances of a post crash fire were greatly reduced
if the battery had departed the aircraft. Shutting off electrical power
close to the source should also reduce the chances of fire following a forced
landing.
The downside of a relay is that there is one more item to fail. If you do not
install it, it can not fail. I vote for using a relay. Your preference may
vary.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=468173#468173
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Is there M39029/63-3XX For 18 AWG Wire?!?!? |
Hi All,
I am rewiring my airplane and am therefore making wire runs to the
Lightspeed Plasma III ignition systems.
The Plasma ignition systems input connector uses DSub 15 plugs so I have
utilized the M39029/63-368 crimp on connectors for all of the 20-24 AWG
wires that push into the connector however I have according to the
directions used an 18 AWG positive wire and an 18 AWG negative wire for
the
power and ground. To make this phase of the project more dramatic, the
Plasma input connector has two positive pins and two negative pins on
its
connector so I need to figure out to go from my single 18 AWG positive
wire
and divide it up into two wires that will each fit into its respective
M39029/63-368 ORANGE-BLUE-GRAY crimp on connector.
Is there a M39029/63-3XX crimp on connector that is designed for 18 to
20
AWG wire?
If not, I could cut off a couple of strands of the 18 AWG wire to get it
to
fit into the 20 AWG connector barrel however that is not very elegant
because the remaining strand(s) will kinda poke out of the wire
insulation
however a needle nose pliers could fix that.
Then the next obstacle to Plasma Bliss is dealing with dividing out the
single wire and making it two wires.
I am considering peeling off a 1 inch section of the insulation of the
single wire about 3 inches away from the wire end and then once that
section
of wire is exposed, place a second wire with the insulation stripped off
the
end onto the exposed conductor and solder the second wire to the first
and
then cover the junction with heat shrink.
To expose the first wire 3 inches up from the end could be possible to
do by
using my wire stripper to make the two cuts by just squeezing the handle
only about =BC of the way to have it cut all the way around the
insulation and
move the insulation about 1/16 of an inch and then exacto off the
remaining
center section.
My soldering skills have much to be desired however if I use a =93second
hands=94 type contraption to hold the two wires together and then use a
clean
soldering iron tip and some flux I could do a respectable job.
I would think that=85IF=85there was an easier way someone here would
have
found/invented it by now.
Also, in the past someone told me that a crimp on butt end connector
creates
a more secure and durable wire splice than if the two ends were soldered
together. Is that true? Perhaps with my soldering skills that would
certainly be the case however for people with decent soldering skills I
am
interested in the actual answer.
Any feedback on this idea/proper suggestions/well wishes would be most
appreciated!!!
..
THANKS!!!
Bill Hunter
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Is there M39029/63-3XX For 18 AWG |
Wire?!?!?
Bill,
First, there is no need for 18ga wire in providing the power. 20Ga
is plenty. So just skip that. Be aware that Klaus does not
recommend anyone ever cut the connector off and reconnect it
their self. Other than not wanting someone to screw up such
a critical part of their ignition system, I don't know what his
motivation is. But be aware that he may not be as interested to
help once someone cuts that off.
Anyway, there's no reason to go 18ga, so just skip that and then
things get easier, and you can run 2 long 20Ga wires to the power
source, or join them into something thicker with your choice in
splice if you wish, further away from the connector.
Tim
On 4/9/2017 9:00 AM, William Hunter wrote:
> Hi All,
>
>
> I am rewiring my airplane and am therefore making wire runs to the
> Lightspeed Plasma III ignition systems.
>
>
> The Plasma ignition systems input connector uses DSub 15 plugs so I have
> utilized the M39029/63-368 crimp on connectors for all of the 20-24 AWG
> wires that push into the connector however I have according to the
> directions used an 18 AWG positive wire and an 18 AWG negative wire for
> the power and ground. To make this phase of the project more dramatic,
> the Plasma input connector has two positive pins and two negative pins
> on its connector so I need to figure out to go from my single 18 AWG
> positive wire and divide it up into two wires that will each fit into
> its respective M39029/63-368 ORANGE-BLUE-GRAY crimp on connector.
>
>
> Is there a M39029/63-3XX crimp on connector that is designed for 18 to
> 20 AWG wire?
>
>
> If not, I could cut off a couple of strands of the 18 AWG wire to get it
> to fit into the 20 AWG connector barrel however that is not very elegant
> because the remaining strand(s) will kinda poke out of the wire
> insulation however a needle nose pliers could fix that.
>
>
> Then the next obstacle to Plasma Bliss is dealing with dividing out the
> single wire and making it two wires.
>
>
> I am considering peeling off a 1 inch section of the insulation of the
> single wire about 3 inches away from the wire end and then once that
> section of wire is exposed, place a second wire with the insulation
> stripped off the end onto the exposed conductor and solder the second
> wire to the first and then cover the junction with heat shrink.
>
>
> To expose the first wire 3 inches up from the end could be possible to
> do by using my wire stripper to make the two cuts by just squeezing the
> handle only about of the way to have it cut all the way around the
> insulation and move the insulation about 1/16 of an inch and then exacto
> off the remaining center section.
>
>
> My soldering skills have much to be desired however if I use a second
> hands type contraption to hold the two wires together and then use a
> clean soldering iron tip and some flux I could do a respectable job.
>
>
> I would think thatIFthere was an easier way someone here would have
> found/invented it by now.
>
>
> Also, in the past someone told me that a crimp on butt end connector
> creates a more secure and durable wire splice than if the two ends were
> soldered together. Is that true? Perhaps with my soldering skills that
> would certainly be the case however for people with decent soldering
> skills I am interested in the actual answer.
>
>
> Any feedback on this idea/proper suggestions/well wishes would be most
> appreciated!!!
>
> ..
>
>
> THANKS!!!
>
>
> Bill Hunter
>
>
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? |
> Also, in the past someone told me that a crimp on butt end connector creates
a more secure and durable wire splice than if the two ends were soldered together.
Is that true?
No, the two methods are equal. Some might argue that soldering is better. The
disadvantage of soldering is that solder wicks into the wire and makes it stiff
which could lead to breaking if subject to vibration. But good support and
a couple of layers of heat shrink will prevent that. Crimped wires also need
support.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=468179#468179
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Endurance bus switch |
At 05:01 AM 4/9/2017, you wrote:
>Hi Bob,
>
>I=99m building an RV-7 and tackling the wiring,
>thank you for sharing the invaluable knowledge in your book.
>I=99ve been grappling with whether or not to
>wire the endurance bus directly through the
>switch or use a relay. The switch is rated at 20
>amps but the bus could conceivably see up to 24
>amps if everything on the bus was on and drawing
>its maximum, eg radio transmitting, transponder
>transponding and GPS charging for example.
The switch 'rating' is largely irrelevant. The
number is an engineer's guide to service life
under tens of thousands of cycles at full load.
Your switch won't see 1000 cycles in its lifetime
and never under full load.
Tell us about this 'endurance' bus . . . what
are your design goals for battery only operations
and what electro-whizzies are fed from this bus?
Bob . . .
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? |
At 09:38 AM 4/9/2017, you wrote:
>
>
> > Also, in the past someone told me that a
> crimp on butt end connector creates a more
> secure and durable wire splice than if the two
> ends were soldered together.=EF=BD Is that true?
no
>No, the two methods are equal. Some might argue
>that soldering is better. The disadvantage of
>soldering is that solder wicks into the wire and
>makes it stiff which could lead to breaking if subject to vibration.
also not true
> But good support and a couple of layers of
> heat shrink will prevent that. Crimped wires also need support.
EXACTLY. risks from stress risers on strands of wire
rise at the TRANSITION from strands (flexible) to
solid (inflexible). That solid thingy happens
whether you solder or mash. Hence the PIDG
design which provides the SAME support to
crimped wires as that which is recommended
for soldered wires as well.
http://tinyurl.com/mz89on7
Bob . . .
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? |
On 4/9/2017 9:00 AM, William Hunter wrote:
>
> Hi All,
>
> I am rewiring my airplane and am therefore making wire runs to the
> Lightspeed Plasma III ignition systems.
>
> The Plasma ignition systems input connector uses DSub 15 plugs so I
> have utilized the M39029/63-368 crimp on connectors for all of the
> 20-24 AWG wires that push into the connector however I have according
> to the directions used an 18 AWG positive wire and an 18 AWG negative
> wire for the power and ground. To make this phase of the project more
> dramatic, the Plasma input connector has two positive pins and two
> negative pins on its connector so I need to figure out to go from my
> single 18 AWG positive wire and divide it up into two wires that will
> each fit into its respective M39029/63-368 ORANGE-BLUE-GRAY crimp on
> connector.
>
> Is there a M39029/63-3XX crimp on connector that is designed for 18 to
> 20 AWG wire?
>
> If not, I could cut off a couple of strands of the 18 AWG wire to get
> it to fit into the 20 AWG connector barrel however that is not very
> elegant because the remaining strand(s) will kinda poke out of the
> wire insulation however a needle nose pliers could fix that.
>
> Then the next obstacle to Plasma Bliss is dealing with dividing out
> the single wire and making it two wires.
>
> I am considering peeling off a 1 inch section of the insulation of the
> single wire about 3 inches away from the wire end and then once that
> section of wire is exposed, place a second wire with the insulation
> stripped off the end onto the exposed conductor and solder the second
> wire to the first and then cover the junction with heat shrink.
>
> To expose the first wire 3 inches up from the end could be possible to
> do by using my wire stripper to make the two cuts by just squeezing
> the handle only about of the way to have it cut all the way around
> the insulation and move the insulation about 1/16 of an inch and then
> exacto off the remaining center section.
>
> My soldering skills have much to be desired however if I use a second
> hands type contraption to hold the two wires together and then use a
> clean soldering iron tip and some flux I could do a respectable job.
>
> I would think thatIFthere was an easier way someone here would have
> found/invented it by now.
>
> Also, in the past someone told me that a crimp on butt end connector
> creates a more secure and durable wire splice than if the two ends
> were soldered together. Is that true? Perhaps with my soldering
> skills that would certainly be the case however for people with decent
> soldering skills I am interested in the actual answer.
>
> Any feedback on this idea/proper suggestions/well wishes would be most
> appreciated!!!
>
> ..
>
> THANKS!!!
>
> Bill Hunter
>
I think there's a drawing in 'the Book' showing how to feed a bigger
power wire into a pair (or more) of the standard pins in a subD. It's
basically what you're describing: a pair of ~6" long 20 ga pigtails
brought together & attached to the larger wire. Soldering works great,
but if you're not confident in your skills, a crimp style butt splice is
fine, too. Solder + heat shrink is cheaper, less bulky, and properly
done, has no more risk of poor connection or breakage from stress
risers. Crimps are more expensive, but much faster and can be achieved
by 'unskilled labor'.
You can split the insulation & splice in another conductor as you
describe, but if the primary is 18 ga or larger, you still have the
issue of fitting it into the 20 ga pin. Snipping strands works, and if
you keep the insulation butted against the end of the pin, there's
little danger of a short, but the whole process is a lot more painful
and risky than just using 2 20 ga pigtails.
Charlie
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? |
Bill,
Bob has extensive advice on how to use multiple pins in a connector for
power. I documented his advice and included photos of my work (5 pins in
parallel) in my blog post Wiring Harness Installed
<https://cheerfulcurmudgeon.com/2016/11/28/wiring-harness-installed/>.
-- Art Z.
--
https://CheerfulCurmudgeon.com/
*"If I am not for myself, who is for me? And if I am only for myself, what
am I? And if not now, when?" Hillel*
Message 10
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Is there M39029/63-3XX For 18 AWG Wire?!?!? |
At 09:00 AM 4/9/2017, you wrote:
>Hi All,
>
>I am rewiring my airplane and am therefore making wire runs to the
>Lightspeed Plasma III ignition systems.
>
>The Plasma ignition systems input connector uses DSub 15 plugs so I
>have utilized the M39029/63-368 crimp on connectors for all of the
>20-24 AWG wires that push into the connector however I have
>according to the directions used an 18 AWG positive wire and an 18
>AWG negative wire for the power and ground. To make this phase of
>the project more dramatic, the Plasma input connector has two
>positive pins and two negative pins on its connector so I need to
>figure out to go from my single 18 AWG positive wire and divide it
>up into two wires that will each fit into its respective
>M39029/63-368 ORANGE-BLUE-GRAY crimp on connector.
>
>Is there a M39029/63-3XX crimp on connector that is designed for 18
>to 20 AWG wire?
Those pins WILL accept a 20AWG wire. Run two pairs of 20AWG,
one for power the other for ground. Let each wire enjoy
its own d-sub pin; bring them together at the source and
ground connections.
The LightSpeed 6-cyl ignition system draws about
2.5A at 2700 rpm . . . the 4-cyl is about 2/3
that amount. The system would perform happily
with a single 22AWG feeder for power and ground.
A pair of 20AWG for each feeder is still . . .
shall we say? . . . exceedingly robust.
A bit of trivia on this topic, you CAN buy pins
for d-subs that will accept larger wires. The crimps
are OUTSIDE the pin cavity in the connector with a
longer stem extending into the connector cavity. They
are expensive and not easy to find and used ONLY
when the LENGTH of the wire run offers an unacceptable
voltage drop within the connector pin's normal rated
current. I've only seen such pins in the wild once in
my lifetime . . . and if memory serves, they were soldered
onto the wires.
The crimped mil-spec pins are rated at 7A under
benign environments . . . I generally never run
them at more than 5 . . . especially when paralleling
for high current applications.
http://tinyurl.com/mzauc8b
I used this technique on a super-sonic target
for the Navy and the process was repeated on some
power distribution components in the B4000 Horizon.
Oh yeah, if you need the too-large wire to compensate
for voltage drop, then it's perfectly acceptable to
prune the strands on an 18AWG to get them into the
20AWG pin. But I'm betting a dollar to a dozen donuts
that the OBAM aircraft owner will NEVER encounter such
a situation. It's also a certainty that the LightSpeed
system secures no performance enhancements with
the pudgy supply wires.
Bob . . .
Message 11
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Is there M39029/63-3XX For 18 AWG Wire?!?!? |
Hi All,
This advice is most helpful.THANKS!!!
Yes I know the Plasma instructions said to not fool with the input
connectors however I dinked up the cable so I had to.Grrr. Since the
ignition system is somewhat important I decided to go with the MIL spec
connector pins. I imagine that solder-on DSub connectors would be the best
way to go however with my soldering skills and lack of patients the crimp on
pins seemed to be the the way to go. I was very careful with each crimp and
did a pull test and they did not fall off. The Eclipse crimper tool is
really good and makes professional crimps even with me using it.
The airplane in question is a Velocity (plastic pusher) and I am running two
Plasma units each connected to the battery terminals of their respective
independent electrical system.
Electrical system 1 has the battery in the nose so its electrical path is
from the battery POS terminal to the CB, to the expensive MIL spec switch
mounted on the panel, to the POS D-Sub pins on the ignition module mounted
way back on the cold side (front) of the firewall and then from the ignition
module NEG pins all the way forward to the NEG terminal of the battery up in
the nose.
Electrical system 2 has the battery under the rear seat so its electrical
path is from the battery POS terminal forward to the CB, to the expensive
MIL spec switch mounted on the panel, and then back to the POS D-Sub pins on
the ignition module mounted way back on the cold side (front) of the
firewall and then from the ignition module NEG pins forward to the NEG
terminal of the battery mounted under the rear seat.
With these long distances I felt that 18 AWG wire was a good idea.
THANKS AGAIN!!!
..
Cheers!!!
Bill Hunter
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Sunday, April 9, 2017 9:14 AM
Subject: Re: AeroElectric-List: Is there M39029/63-3XX For 18 AWG Wire?!?!?
At 09:00 AM 4/9/2017, you wrote:
Hi All,
I am rewiring my airplane and am therefore making wire runs to the
Lightspeed Plasma III ignition systems.
The Plasma ignition systems input connector uses DSub 15 plugs so I have
utilized the M39029/63-368 crimp on connectors for all of the 20-24 AWG
wires that push into the connector however I have according to the
directions used an 18 AWG positive wire and an 18 AWG negative wire for the
power and ground. To make this phase of the project more dramatic, the
Plasma input connector has two positive pins and two negative pins on its
connector so I need to figure out to go from my single 18 AWG positive wire
and divide it up into two wires that will each fit into its respective
M39029/63-368 ORANGE-BLUE-GRAY crimp on connector.
Is there a M39029/63-3XX crimp on connector that is designed for 18 to 20
AWG wire?
Those pins WILL accept a 20AWG wire. Run two pairs of 20AWG,
one for power the other for ground. Let each wire enjoy
its own d-sub pin; bring them together at the source and
ground connections.
The LightSpeed 6-cyl ignition system draws about
2.5A at 2700 rpm . . . the 4-cyl is about 2/3
that amount. The system would perform happily
with a single 22AWG feeder for power and ground.
A pair of 20AWG for each feeder is still . . .
shall we say? . . . exceedingly robust.
A bit of trivia on this topic, you CAN buy pins
for d-subs that will accept larger wires. The crimps
are OUTSIDE the pin cavity in the connector with a
longer stem extending into the connector cavity. They
are expensive and not easy to find and used ONLY
when the LENGTH of the wire run offers an unacceptable
voltage drop within the connector pin's normal rated
current. I've only seen such pins in the wild once in
my lifetime . . . and if memory serves, they were soldered
onto the wires.
The crimped mil-spec pins are rated at 7A under
benign environments . . . I generally never run
them at more than 5 . . . especially when paralleling
for high current applications.
http://tinyurl.com/mzauc8b
I used this technique on a super-sonic target
for the Navy and the process was repeated on some
power distribution components in the B4000 Horizon.
Oh yeah, if you need the too-large wire to compensate
for voltage drop, then it's perfectly acceptable to
prune the strands on an 18AWG to get them into the
20AWG pin. But I'm betting a dollar to a dozen donuts
that the OBAM aircraft owner will NEVER encounter such
a situation. It's also a certainty that the LightSpeed
system secures no performance enhancements with
the pudgy supply wires.
Bob . . .
Message 12
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Is there M39029/63-3XX For 18 AWG Wire?!?!? |
>
>Electrical system 2 has the battery under the rear seat so its
>electrical path is from the battery POS terminal forward to the CB,
>to the expensive MIL spec switch mounted on the panel, and then back
>to the POS D-Sub pins on the ignition module mounted way back on the
>cold side (front) of the firewall and then from the ignition module
>NEG pins forward to the NEG terminal of the battery mounted under
>the rear seat.
>
>With these long distances I felt that 18 AWG wire was a good idea.
Not very quantified . . .
Resistance of 22AWG wire = 0.016 ohms/foot = 16mv drop per amp
per foot of wire
20AWG wire = 0.010 ohms/foot = 10mv drop per amp
per foot of wire
18AWG wire = 0.006 ohms/foot = 6mv drop per amp per
foot of wire
Assume 20foot round trip from battery(+) to battery (-) and
2 amps of appliance draw.
22AWG drops 0.640 volts
20AWG drops 0.400 volts
18AWG drops 0.240 volts
Assuming your power pathways totaled 20 feet and
you indeed require 2A of supply power, voltage
variations presented over the range of wire
sizes explored above are trivial.
Further, LightSpeed's passion for hooking
things right to the battery is without president
in certified general aviation. The only folks
I know of that do this routinely are the kids
with 1000 Watt boom boxes in their vehicles.
In fact, driving BOTH systems through a common source
configuration violates the common sense for in the
analysis and mitigation of failure modes.
Bob . . .
Message 13
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Is there M39029/63-3XX For 18 AWG Wire?!?!? |
Bob, just curious... how comfortable are you with using the M39029/63-3
crimp on pins for the ignition system D-Sub connector as opposed to the
solder on type?
Thanks again,
Bill Hunter
On Apr 9, 2017 1:42 PM, "Robert L. Nuckolls, III" <
nuckolls.bob@aeroelectric.com> wrote:
>
> Electrical system 2 has the battery under the rear seat so its electrical
> path is from the battery POS terminal forward to the CB, to the expensive
> MIL spec switch mounted on the panel, and then back to the POS D-Sub pins
> on the ignition module mounted way back on the cold side (front) of the
> firewall and then from the ignition module NEG pins forward to the NEG
> terminal of the battery mounted under the rear seat.
>
> With these long distances I felt that 18 AWG wire was a good idea.
>
>
> Not very quantified . . .
>
> Resistance of 22AWG wire = 0.016 ohms/foot = 16mv drop per amp per foot
> of wire
> 20AWG wire = 0.010 ohms/foot = 10mv drop per amp per foot
> of wire
> 18AWG wire = 0.006 ohms/foot = 6mv drop per amp per foot
> of wire
>
> Assume 20foot round trip from battery(+) to battery (-) and
> 2 amps of appliance draw.
>
> 22AWG drops 0.640 volts
> 20AWG drops 0.400 volts
> 18AWG drops 0.240 volts
>
> Assuming your power pathways totaled 20 feet and
> you indeed require 2A of supply power, voltage
> variations presented over the range of wire
> sizes explored above are trivial.
>
> Further, LightSpeed's passion for hooking
> things right to the battery is without president
> in certified general aviation. The only folks
> I know of that do this routinely are the kids
> with 1000 Watt boom boxes in their vehicles.
>
> In fact, driving BOTH systems through a common source
> configuration violates the common sense for in the
> analysis and mitigation of failure modes.
>
> <#m_-4996803437017520622_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> Bob . . .
>
Message 14
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Is there M39029/63-3XX For 18 AWG Wire?!?!? |
At 01:55 PM 4/9/2017, you wrote:
>Bob, just curious... how comfortable are you
>with using the=C2 M39029/63-3 crimp on pins for
>the ignition system D-Sub connector as opposed to the solder on type?
No difference. Properly installed wires
passing though quality connectors are
generally considered to have failure
rates less than one per billion flight
hours.
I've read failure rate studies on dozens
of systems having high orders of system
criticality as demonstrated by detailed
studies of component failure rates for the
resistors, transistors, capacitors and
all manner of electro-jelly-beans. Then
they run even the simplest software
through rigorous certification and configuration
control protocols.
After all the bureaucratic thrashing dies
down you can ask: "Does this appliance have
and critical power or signal pathways that
pass through connectors?" "Of course," they
say. "But failure rates for those assemblies
are insignificant in the grand scheme of things."
For YOUR personal failure analysis consider
that you have TWO ignition systems. The engine
runs very happily on ONE system. If one system
fails, you probably won't notice it in flight
but you will at next pre-flight. Next consider
the probability that BOTH systems will go
T.U. on any single tank full of gas.
You can have terrible failure rates for each
system and still fly with confidence . . . like
we've been doing with dual magnetos for over
100 years.
If it were my airplane, one system would run
from the battery bus, the other would run
from the e-bus. Wire with single 20AWG feeders
and stay away from hooking anything directly
to the battery(ies).
It's far too easy to get wrapped around 'reliability
axles' and loose track of the real risk factors.
That's what happened with N811HB about ten years
ago http://tinyurl.com/msfmldj
KISS
Bob . . .
Message 15
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Today's trivia dump . . . |
> On Apr 7, 2017, at 5:08 PM, Robert L. Nuckolls, III <nuckolls.bob@aeroelectric.com>
wrote:
> I would sure build in some sort of limiting.
You mentioned 40A. Would that be our target for max current in a system like this?
Would we want adjustability, and if so, through what range?
I have zero PIC time with a spot welder, hence the questions...
Eric
Message 16
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Is there M39029/63-3XX For 18 AWG Wire?!?!? |
Very good and comforting information Bob. As always I am very grateful for
your advice!!!
Thanks,
Bill Hunter
On Apr 9, 2017 7:59 PM, "Robert L. Nuckolls, III" <
nuckolls.bob@aeroelectric.com> wrote:
> At 01:55 PM 4/9/2017, you wrote:
>
> Bob, just curious... how comfortable are you with using the=C3=82 M39029
/63-3
> crimp on pins for the ignition system D-Sub connector as opposed to the
> solder on type?
>
>
> No difference. Properly installed wires
> passing though quality connectors are
> generally considered to have failure
> rates less than one per billion flight
> hours.
>
> I've read failure rate studies on dozens
> of systems having high orders of system
> criticality as demonstrated by detailed
> studies of component failure rates for the
> resistors, transistors, capacitors and
> all manner of electro-jelly-beans. Then
> they run even the simplest software
> through rigorous certification and configuration
> control protocols.
>
> After all the bureaucratic thrashing dies
> down you can ask: "Does this appliance have
> and critical power or signal pathways that
> pass through connectors?" "Of course," they
> say. "But failure rates for those assemblies
> are insignificant in the grand scheme of things."
>
> For YOUR personal failure analysis consider
> that you have TWO ignition systems. The engine
> runs very happily on ONE system. If one system
> fails, you probably won't notice it in flight
> but you will at next pre-flight. Next consider
> the probability that BOTH systems will go
> T.U. on any single tank full of gas.
>
> You can have terrible failure rates for each
> system and still fly with confidence . . . like
> we've been doing with dual magnetos for over
> 100 years.
>
> If it were my airplane, one system would run
> from the battery bus, the other would run
> from the e-bus. Wire with single 20AWG feeders
> and stay away from hooking anything directly
> to the battery(ies).
>
> It's far too easy to get wrapped around 'reliability
> axles' and loose track of the real risk factors.
> That's what happened with N811HB about ten years
> ago http://tinyurl.com/msfmldj
>
> KISS
>
>
> Bob . . .
>
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|