Today's Message Index:
----------------------
1. 01:51 AM - Re: Re: Solicitation for opinions on backups (Peter Pengilly)
2. 03:32 AM - Replacement crimpers (Ralph Hoover)
3. 06:00 AM - Re: Re: Solicitation for opinions on backups (Bill Watson)
4. 08:28 AM - Any know is there a typical faliure mode for Soild State Relays (Jeffrey Skiba)
5. 08:58 AM - Re: Re: Solicitation for opinions on backups (Robert L. Nuckolls, III)
6. 09:44 AM - Re: Any know is there a typical faliure mode for Soild State Relays (Vern Little)
7. 10:01 AM - Re: Any know is there a typical failure mode for Solid State Relays (Bob McCallum)
8. 10:11 AM - Switch schematic (Carlos Trigo)
9. 10:30 AM - Re: Switch schematic (rayj)
10. 10:51 AM - Re: Switch schematic (rayj)
11. 01:38 PM - Re: Any know is there a typical faliure mode for Soild State Relays (Robert L. Nuckolls, III)
12. 06:09 PM - Re: Any know is there a typical faliure mode for Soild State R (Eric M. Jones)
13. 09:00 PM - Re: Any know is there a typical faliure mode for Soild State Relays ()
14. 09:52 PM - Re: Any know is there a typical faliure mode for Soild State Relays (Jeff Luckey)
Message 1
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| Subject: | Re: Solicitation for opinions on backups |
Don,
My opinion is that I would provide power to your EFIS and main radios
that does not involve the VPX.
You have 2 alternators, so if the engine is turning you will likely have
a power supply.
When stuff goes wrong the work load goes through the roof very quickly,
so keeping as much of your panel working as possible will minimise the
rise in workload - and therefore your ability to continue to fly the
airplane. I would suggest a D1 and an iPad are already plan f rather
than plan b.
Plan b should make the failure of any one component (including the VPX)
almost transparent to the pilot. That means providing power to the EFIS
and main radio that does not involve the VPX. It would be daft to have
power available but a dark panel because one component in your system
went down.
Peter
On 22/12/2013 03:43, donjohnston wrote:
>
>
>> Please forgive my tongue in cheek reference to over-worrying
>> a problem.
> Apologies. I was unable to discern the location of your tongue for that post.
[Laughing]
>
>
>> My intent was to highlight a common problem with plug-n-play
>> responses to incomplete questions.
> And I wasn't really looking for an answer since I really didn't have a true question.
I was really just looking (fishing, if you will) for opinions as to
how far is too far when dealing with putting in "backups".
>
> My approach is fairly straightforward (at least for me).
>
> I'm running a standard, stock aircraft engine, mags (not an electronic ignition).
My only deviation from what's been used in the foundation of GA aircraft
for years is the VP-X. If the stock alternator fails, I've got a B&C SD-20. If
that fails, I've got the battery. If the VP-X fails, the engine will continue
producing power (the boost pump can pull power from the VP-X or directly from
the battery). I'll be able to keep the shiny side up with the Dynon D1 for
up to four hours (much longer than the battery would probably last). I've got
a iPad with a GPS and a Garmin 396 to help me figure out where I'm going.
>
> So I think that I've got a good Plan B, C, D, E and F.
>
> I was just looking for opinions (not answers, opinions) on whether the additional
wire, hardware, etc. required to keep the EFIS glowing happily running after
the unlikely event of a VP-X failure was worth the trouble. And since I wasn't
born yesterday, I know that opinions are like buttholes (everyone else's
stink).
>
> We cool? 8)
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=416032#416032
>
>
Message 2
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| Subject: | Replacement crimpers |
OC asked about the simple procedure for AMP crimp QA.
Their PIDG crimpers have a witness mark in the die that is visible in a crimp.
It at least allows you to know that the proper crimper was used. The crimpers
is also controlled cycle so that it must be closed all the way before it will
release.
Ralph
Sent from my iPad
Message 3
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| Subject: | Re: Solicitation for opinions on backups |
After reading this comment, I finally decided to actually read the
Vertical Power overview. When I was designing my electrical system and
panel 5 or 6 years ago, VP-X wasn't on my scope and I never looked back.
If a recommendation is that I need to backup wire around the VP-X, I had
to go "huh?"
I can see that it can simplify the electrical system design task and
adds some functionality. I can see the appeal.
do not archive
> My opinion is that I would provide power to your EFIS and main radios
> that does not involve the VPX.
>
> You have 2 alternators, so if the engine is turning you will likely
> have a power supply.
>
> When stuff goes wrong the work load goes through the roof very
> quickly, so keeping as much of your panel working as possible will
> minimise the rise in workload - and therefore your ability to continue
> to fly the airplane. I would suggest a D1 and an iPad are already plan
> f rather than plan b.
>
> Plan b should make the failure of any one component (including the
> VPX) almost transparent to the pilot. That means providing power to
> the EFIS and main radio that does not involve the VPX. It would be
> daft to have power available but a dark panel because one component in
> your system went down.
Message 4
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| Subject: | Any know is there a typical faliure mode for Soild |
State Relays
Any know is there a typical failure mode for Solid State Relays?
Like do they typically fail OPEN ??? or do they Typical fail CLOSED (just l
ike sometimes of a typical mechanical relay that the points weld together o
r the spring fails ?)
I am considering using solid state relays to replace mechanical relays but
do not know if the ssr has a failure mode worse than them.
I have attached one relay I found thus far to possibly replace a hydraulic
motor contactor for a landing gear pump.
Thanks in advance and HAPPY HOLIDAYS !
________________________________
No virus found in this message.
Checked by AVG - www.avg.com<http://www.avg.com>
Message 5
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| Subject: | Re: Solicitation for opinions on backups |
At 07:58 AM 12/22/2013, you wrote:
After reading this comment, I finally decided to actually read the
Vertical Power overview. When I was designing my electrical system
and panel 5 or 6 years ago, VP-X wasn't on my scope and I never looked back.
GOOD FOR YOU! It pays to be informed . . .
If a recommendation is that I need to backup wire around the VP-X, I
had to go "huh?"
I can see that it can simplify the electrical system design task and
adds some functionality. I can see the appeal.
I don't think anyone has recommended any such thing
yet. The phrase "catastrophic failure" was used as a
worry-topic for the VP-X. I stretched the premise
past the absurd by suggesting that 'meteors
through the crankcase' might also be considered.
The knowledgeable and skilled retorts might be
something like this:
"well considered chances of meteors through the
crankcase is Z.F x 10 to the minus gazillion
events per flight hour and the chances of a failure
that cripples multiple systems in a VP-X system is
G.C x 10 to the minus 6, 7 or 8 events per flight
hour, hence there are NO practical worry points for
either event.
Given that nobody has come forth with a skilled
MTBF study on VP-X (and none is expected), then
we are left with the kinds of analysis that can
be accomplished by judicious consideration of
design features . . . or failure modes effects
analysis.
This is an activity that I encouraged Marc to
conduct throughout the evolutionary advances
to his design. We met in the pilot's lounge
of KAAO about ten years ago when the VP-X system
was but a gleam in his eye.
Unlike some other products offered onto the OBAM
and even TC aviation markets, there has been no
hue and cry of customer dissatisfaction nor flurry
of ADs against VP-X products so I am hopeful that
Marc took my advice to heart and had conducted
due diligence in the design, manufacturing and
marketing of his products.
At the same time, all of you as mney paying
consumers of those products have every right
to make detailed inquiry as to his design and
verification processes. If you value your
aluminum AND bones, then you have a DUTY to
make such inquiry.
The VP-X system is capable of taking on task
criticality on a par with say an engine. We cannot
carry back-up engines. Unless we have a
confidence level in the VP-X system that is
within a few orders of magnitude of that
which we assign to engines, then the question
of "back up" becomes more problematic.
The difference here is whether we add a back-up
because we DON'T know or because we DO KNOW.
My bosses have paid me to find out such things
for 50 years. . . . and yes, I'm reasonably certain
that meteor shields built into the cowl will only
add cost, weight and no value. You are your own
boss. Okay boss, what's the drill going to be
for assessing the necessity and/or value of
adding a backup feature YOUR implementation
of the VP-X system?
Further, arriving at some useful conclusion will
be much easier if it's crafted and sifted here
on the List. GOOD information for doing . . .
or NOT doing things is worth sharing.
Bob . . .
Message 6
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| Subject: | Re: Any know is there a typical faliure mode for Soild |
State Relays
The failure mode for these devices are highly dependent on the internal
construction. Contacting the manufacturer is only way to be sure.
If it was just the internal powerFET that was the issue, the failure
modes are well understood but details of the mechanical packaging may
dominate.
Vern
From: Jeffrey Skiba
Sent: Sunday, December 22, 2013 8:27 AM
Subject: AeroElectric-List: Any know is there a typical faliure mode for
Soild State Relays
Any know is there a typical failure mode for Solid State Relays?
Like do they typically fail OPEN ??? or do they Typical fail CLOSED
(just like sometimes of a typical mechanical relay that the points weld
together or the spring fails ?)
I am considering using solid state relays to replace mechanical relays
but do not know if the ssr has a failure mode worse than them.
I have attached one relay I found thus far to possibly replace a
hydraulic motor contactor for a landing gear pump.
Thanks in advance and HAPPY HOLIDAYS !
-------------------------------------------------------------------------
-------
No virus found in this message.
Checked by AVG - www.avg.com
p>
-------------------------------------------------------------------------
-------
No virus found in this message.
Checked by AVG - www.avg.com
12/22/13
Message 7
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| Subject: | Any know is there a typical failure mode for Solid |
State Relays
Jeffrey;
I have not used the DC relays which you've linked to, but at work we have
used the AC version of this particular brand of relay for controlling
heating elements for approximately 25 years. Their biggest enemy, as with a
lot of electronics, is heat. Because we do not implement large heat sinks to
cool these relays ($cost$) we oversize them by approx 4X to ensure no
heating issues and typically see less than .1% failures. (we do bolt them to
steel enclosures, so they have some heat sinking) I have no statistics on
the relative age or loads on the failed units. When the failures do occur
they are almost always failure to close (in other words fail open) I have
had one and only one fail closed however, so it would appear both failure
modes are possible. We have also experimented with sizing them to approx 2X
load current and have seen the five year failure rates rise, in this group,
to approx 5%. As a result we returned to using the 50 amp models for greater
reliability of our product. (loads are in the 3 to 14 amp range) While this
anecdotal information may or may not apply to the DC versions of Crydom's
product we're quite satisfied with the AC versions performance. I should
also mention that the equipment we manufacture typically employing these
relays runs 24/7 and these relays are controlled via a temperature
controller cycling on/off up to as much as 50 cycles per minute, so we give
them a good workout although we lightly load them.
Bob McC
_____
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jeffrey
Skiba
Sent: Sunday, December 22, 2013 11:27 AM
Subject: AeroElectric-List: Any know is there a typical faliure mode for
Soild State Relays
Any know is there a typical failure mode for Solid State Relays?
Like do they typically fail OPEN ??? or do they Typical fail CLOSED (just
like sometimes of a typical mechanical relay that the points weld together
or the spring fails ?)
I am considering using solid state relays to replace mechanical relays but
do not know if the ssr has a failure mode worse than them.
I have attached one relay I found thus far to possibly replace a hydraulic
motor contactor for a landing gear pump.
Thanks in advance and HAPPY HOLIDAYS !
_____
No virus found in this message.
Checked by AVG - www.avg.com
p>
Message 8
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| Subject: | Switch schematic |
Guys
Since I am not sure if this switch will suite my need
can somebody please post a drawing of its eletric schematic.
Thanks
Carlos
P.S. - I am looking for a switch for the fuel pump that can be powered from
2 independent power sources, being the middle position the OFF position
Message 9
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| Subject: | Re: Switch schematic |
Message 10
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| Subject: | Re: Switch schematic |
Hope these will answer your questions.
http://www.jameco.com/1/1/40651-2tl1-10a-switch-toggle-ms27408-4a.html
http://www.jameco.com/Jameco/Products/ProdDS/1817426.pdf
Raymond Julian
Kettle River, MN.
"And you know that I could have me a million more friends,
and all I'd have to lose is my point of view." - John Prine
On 12/22/2013 12:11 PM, Carlos Trigo wrote:
>
> Guys
>
> Since I am not sure if this switch will suite my need
>
Picture removed.
>
> can somebody please post a drawing of its eletric schematic.
>
> Thanks
>
> Carlos
>
> P.S. -- I am looking for a switch for the fuel pump that can be
> powered from 2 independent power sources, being the middle position
> the OFF position
>
Message 11
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| Subject: | Re: Any know is there a typical faliure mode for |
Soild State Relays
At 10:27 AM 12/22/2013, you wrote:
Any know is there a typical failure mode for Solid State Relays?
Like do they typically fail OPEN ??? or do they Typical fail CLOSED (just
like sometimes of a typical mechanical relay that the points weld together
or the spring fails ?)
I am considering using solid state relays to replace mechanical relays but
do not know if the ssr has a failure mode worse than them.
I have attached one relay I found thus far to possibly replace a hydraulic
motor contactor for a landing gear pump.
Thanks in advance and HAPPY HOLIDAYS !
They can fail in ANY mode. I.e. stuck closed or stuck open.
It depends on the stress that might have precipitated the
failure. Were I considering such a device for use in a
TC aircraft, the litany of deliberations goes something
like this:
1. How many ways can this part fail?
2. How will each failure affect system operation?
3. How will I know it failed?
4. Is the failure pre-flight detectable?
5. Is failure of this part, in any failure mode, likely to create
a hazard to flight?
6. Will failure of this part be likely to overtax my piloting
skills for comfortably terminating the flight?
Come of the gate ASSUMING the part will fail in
every conceivable way . . . how do the answers
to the above questions affect the way you use the
part and how you react to the failure.
Rule #1 Things Break
Rule #2 Systems shall be designed so that when things
break, no immediate hazard is created.
Rule #3 Things needed for comfortable termination of
flight require backup or special considerations
to insure operation and availability.
Rule #4 Upgrading the quality or reliability of a part
shall be because you are tired of replacing it
or want some new feature, not because it damned
near got you killed.
Suggest you review this short piece on FMEA. The FMEA worka
around the problem of not knowing the whether or not the
part has established reliability numbers. Assume that it
will fail, rework the design or craft a plan-b so you can
be pleasantly surprised when it never fails but have a
comfortable response if it does.
This philosophy for systems design is spelled out in
more detail here
http://tinyurl.com/ljl9qe6
http://tinyurl.com/lfkm2fl
As a final note, be aware that your hydraulic pump
motor is probably a permanent magnet variety with
hefty inrush current. Make sure the device you pick
can stand 500-1000 amp inrush for a few milliseconds . . .
i.e. "rated" for motor or large incandescent lamp
control.
Bob . . .
Message 12
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| Subject: | Re: Any know is there a typical faliure mode for Soild |
State R
There is arguably no "typical" failure mode for anything at all.
If there were, the engineers would be happy to see it because it would be an easy
fix.
A failure can be "typical" if a device is being misused. "Hey, the device typically
fails if being misused!" I'll bet there are a million engineering stories
there.
Note: I have sold many SSRs, and I sometimes get "complaints" from customers who
think that the apparent SSR no load output voltage when the relay is OFF indicates
some flaw. Hmmmmmm....Well...there is always an no-load output voltage
on every switch or relay...ON or OFF. But an SSR won't pass more than a microamp
or so when OFF. So it won't light an LED. It is DEFINED as OFF for all practical
purposes.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=416083#416083
Message 13
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| Subject: | Re: Any know is there a typical faliure mode for Soild |
State Relays
That=99s what I did...less weight, less space, less environmental
issues, cleaner operation (no contact bounce), etc.
http://www.berkut13.com/berkut50.htm#SSR
If you hydraulic system is anything like mine, you should also be used
the snap action hydraulic pressure switches.
Good luck,
James
Berkut/Race 13
www.berkut13.com
Facebook: Berkut13
From: Jeffrey Skiba
Sent: Sunday, December 22, 2013 10:27 AM
Subject: AeroElectric-List: Any know is there a typical faliure mode for
Soild State Relays
Any know is there a typical failure mode for Solid State Relays?
Like do they typically fail OPEN ??? or do they Typical fail CLOSED
(just like sometimes of a typical mechanical relay that the points weld
together or the spring fails ?)
I am considering using solid state relays to replace mechanical relays
but do not know if the ssr has a failure mode worse than them.
I have attached one relay I found thus far to possibly replace a
hydraulic motor contactor for a landing gear pump.
Thanks in advance and HAPPY HOLIDAYS !
-------------------------------------------------------------------------
-------
No virus found in this message.
Checked by AVG - www.avg.com
p>
Message 14
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| Subject: | Re: Any know is there a typical faliure mode for Soild |
State Relays
they sure are pricey - $130 ea. @ Mouser, ouch!=0A=0A=0A=0A________________
________________=0A From: "berkut13@berkut13.com" <berkut13@berkut13.com>
=0ATo: aeroelectric-list@matronics.com =0ASent: Sunday, December 22, 2013 8
:59 PM=0ASubject: Re: AeroElectric-List: Any know is there a typical faliur
e mode for Soild State Relays=0A =0A=0A=0A =0AThat=99s what I did...l
ess weight, less space, less environmental issues, =0Acleaner operation (no
contact bounce), etc. =0A=C2-=0Ahttp://www.berkut13.com/berkut50.htm#SSR
=0A=C2-=0AIf you hydraulic system is anything like mine, you should also
be used the =0Asnap action hydraulic pressure switches.=0A=C2-=0AGood luc
k,=0AJames=0ABerkut/Race 13=0Awww.berkut13.com=0AFacebook: Berkut13=0A=C2
-=C2-=0AFrom: Jeffrey Skiba =0ASent: Sunday, December 22, 2013 10:27 AM
=0ATo: aeroelectric-list@matronics.com =0ASubject: AeroElectric-List: Any k
now is there a typical faliure mode =0Afor Soild State Relays=0A=C2- Any
=0Aknow is there a typical failure mode for Solid State =0ARelays?=0A =C2
-=0ALike =0Ado they typically fail OPEN ??? or do they Typical fail CLOSE
D (just like =0Asometimes of a typical mechanical relay that the points wel
d together or the =0Aspring fails ?)=0A =C2-=0AI =0Aam considering using
solid state relays to replace mechanical relays but do not =0Aknow if the s
sr has a failure mode worse than them. =0A =C2-=0AI =0Ahave attached one
relay I found thus far to possibly replace a hydraulic motor =0Acontactor f
or a landing gear pump.=0A =C2-=0AThanks =0Ain advance and HAPPY HOLIDAYS
!=0A________________________________=0A =0ANo virus found in this =0Amess
-========================
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