Today's Message Index:
----------------------
1. 07:12 AM - Re: latching relays (user9253)
2. 08:45 AM - Re: Need help in reviewing Z10/8 arch for dual Lightspeed ign. (plevyakh)
3. 08:45 AM - Re: Re: latching relays (Jeff Luckey)
4. 01:27 PM - Bob Nuckolls - advice (Fergus Kyle)
5. 02:41 PM - Bob nuckolls - advice 2 (Fergus Kyle)
6. 03:49 PM - Transient_voltage_suppression_diode failure ()
7. 04:57 PM - Re: Re: Need help in reviewing Z10/8 arch for dual Lightspeed ign. (Robert L. Nuckolls, III)
8. 07:06 PM - Re: Power for Checking Systems Out on the Ground (Tundra10)
9. 08:00 PM - Re: Re: latching relays (Robert L. Nuckolls, III)
10. 08:43 PM - Re: Bob Nuckolls - advice (Robert L. Nuckolls, III)
11. 08:44 PM - Re: Bob nuckolls - advice 2 (Robert L. Nuckolls, III)
12. 09:24 PM - Re: Transient_voltage_suppression_diode failure (Robert L. Nuckolls, III)
13. 09:35 PM - Z-12 and Plasma II ignition (fedico94@mchsi.com)
14. 10:07 PM - Re: Re: Power for Checking Systems Out on the Ground (Robert L. Nuckolls, III)
15. 11:02 PM - Current draw for lighting Buss (MLWynn@aol.com)
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: | Re: latching relays |
> Circuits like these do have their places but I don't think controlling the coil
of a master solenoid is one of them.
> This sort of smells like a solution looking for a problem. Keep in mind that
when you place more components in the critical path, the reliability of the system
goes down - no matter how reliable those components are.
> In the case of master solenoids, (as Bob & others point out) they have proven
to be pretty darn reliable. Therefore so I would be reluctant to "over-engineer"
a solution to a problem that doesn't exist.
I agree with what you are saying except for the "critical path". There should
always be a backup plan like an alternate feed path. A backup plan will turn
a critical component into a non-critical one. I am not recommending reduced current
to the master contactor for most installations. But it will be of benefit
to systems that have limited generating power, or to prolong battery life
when the alternator fails. A contactor coil operating at reduced voltage will
generate less heat and thus be even more unlikely to fail.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=334067#334067
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: Need help in reviewing Z10/8 arch for dual Lightspeed |
ign.
Bob,
Thanks for the quick reply. I'll make the tweaks.
Regarding your question on the SD8 Low Volt Warning light....
> "Which drawing? Warning lights shown on any of my drawings become surplus if
you've got lv warning built into other systems.
The only other LOW VOLT light I have is on the L-60 circuit.
Here's a clearer picture on my question regarding the SD8 Alternator LOW VOLT Warning
light wiring. My goal here was that when running just on the SD8, I could
use a low voltage warning for the SD-8 to indicate when the battery is actually
carrying part of the load. At 2700 Prop RPM (SD8 @ 3500 RPM) I get 8.4
to 10.1 amps with high fuel consumption. Having the Low Volt light allows me
to make the tradeoff in flight, depending on the distance to destination.
I've sized my endurance bus to 3.7V....but if I wanted to keep some equipment on
with the SD8 I'd like to be able to make that tradeoff to help get me down (assuming
IFR, in the soup).
So directly my question is....by swapping in the LED light on the highlighted circuit
is it wired correctly?
Since I couldn't find a Z-architecture that had this included, I used the B&C SD8
Power distribution diagram as reference on where to pull the light warning
signal.
Also can you please explain how the OVM-14 module works in tripping the light to
come on....or point me to one of your articles that explains that better. I'm
not clear on how this works.
Thank-you,
Howard
--------
Howard Plevyak
GlaStar / North Bend, Ohio
hplevyak@mac.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=334084#334084
Attachments:
http://forums.matronics.com//files/bandc_sd8_schematic_144.png
http://forums.matronics.com//files/sd8_low_volt_circuit_844.png
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: | Re: latching relays |
WARNING - STANDBY FOR LEVEL 4 NIT-PICKING. IF YOUR'RE NOT REALLY INTO THIS,
DO NOT WASTE YOUR TIME
I'm gonna provide MY definitions for some of the terms we are throwing
around (just 'cause it's a slow morning around here)
Let's talk about Critical Path (CP 'cause I'm a lazy typist) and Redundant
Circuitry (RC).
Critical Path:
The chain of components required to make a circuit operate as designed.
Example:
Circuit breaker -> switch -> contactor coil and the wiring that connects
them. All those things are in the CP because if any one fails, the circuit
stops working. [Let's add an LED in parallel w/ the coil (to give the
operator a visual indication) - I would say that the LED is not in the CP]
Every circuit has a CP. (regardless of other circuits that may be added for
redundancy)
If every circuit has a CP and adding components to the CP reduces
reliability, we can still increase reliability by adding a Redundant
Circuit. The RC still has its own CP, but the reliability of the SYSTEM
goes up.
----------
I agree that reduced coil current may add to coil longevity but these
devices have proven to be so reliable that I don't think it's worth the
effort.
-Jeff
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of user9253
Sent: Wednesday, March 16, 2011 06:08
Subject: AeroElectric-List: Re: latching relays
> Circuits like these do have their places but I don't think controlling the
coil of a master solenoid is one of them.
> This sort of smells like a solution looking for a problem. Keep in mind
that when you place more components in the critical path, the reliability of
the system goes down - no matter how reliable those components are.
> In the case of master solenoids, (as Bob & others point out) they have
proven to be pretty darn reliable. Therefore so I would be reluctant to
"over-engineer" a solution to a problem that doesn't exist.
I agree with what you are saying except for the "critical path". There
should always be a backup plan like an alternate feed path. A backup plan
will turn a critical component into a non-critical one. I am not
recommending reduced current to the master contactor for most installations.
But it will be of benefit to systems that have limited generating power, or
to prolong battery life when the alternator fails. A contactor coil
operating at reduced voltage will generate less heat and thus be even more
unlikely to fail.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=334067#334067
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: | Bob Nuckolls - advice |
Bob,
I realise I should test for myself, but thought it might apply to
others:
I am using a DB25 female and male pair for quick disconnect to accommodate
up to #18 wire runs for future circuits in my instrument panel. [The whole
panel OR each sub-panel is meant to be dismountable].
Since it will hold up to 12 + and - runs, I measured the male pins at 0.04
inches in diameter from the pack of 100, labelled as `S604P'. These are
solid, not stamped pins and sockets.
Can I consider these to carry a constant 4 amps if not bundled tightly
together? AND could I parallel a set of three to carry a constant 10A in
similar circumstances?
I would like to know I'm operating in a`conservative' milieu and
don't plan to run cfuture equipment at greater than 10A.
Cheers, Ferg
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: | Bob nuckolls - advice 2 |
Further to my previous:
A measured pin diameter is 0.04 inches, radius is 0.02", area is
(0.02x0.02)xpi = 0.00125663 sq.in. x 645.16 = 0.8107319 sq.mm.
This comes out between AWG20 and AWG18 - call it AWG #19.
That would infer that the pin carries about 6-7 amps, having regard for
irregular measuring, improper meshing of pin/socket, differing metals, temp,
bundling etc.
Am I in the ball park?
ferg
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: | Transient_voltage_suppression_diode failure |
3/16/2011
Hello Fellow Aeroelectric Listers, You may be interested in the attachment
and the below information:
http://en.wikipedia.org/wiki/Transient_voltage_suppression_diode
'OC' Baker Says: "The best investment we can make is the time and effort to
gather and understand knowledge."
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: Need help in reviewing Z10/8 arch for dual |
Lightspeed ign.
At 11:40 AM 3/16/2011, you wrote:
>
>Bob,
>Thanks for the quick reply. I'll make the tweaks.
>
>Regarding your question on the SD8 Low Volt Warning light....
>
> > "Which drawing? Warning lights shown on any of my drawings become
> surplus if you've got lv warning built into other systems.
>
>The only other LOW VOLT light I have is on the L-60 circuit.
>
>Here's a clearer picture on my question regarding the SD8 Alternator
>LOW VOLT Warning light wiring. My goal here was that when running
>just on the SD8, I could use a low voltage warning for the SD-8 to
>indicate when the battery is actually carrying part of the load. At
>2700 Prop RPM (SD8 @ 3500 RPM) I get 8.4 to 10.1 amps with high
>fuel consumption. Having the Low Volt light allows me to make the
>tradeoff in flight, depending on the distance to destination.
These are NOT the kinds of things you want to be doing
in flight. When the big guy wanders off into the weeds,
then you should have a Plan-B for the little guy's
task. When A fails then B and continue flight to
airport of intended destination.
You don't need a light to tell you anything that
is pre-ordained by planing.
>I've sized my endurance bus to 3.7V....but if I wanted to keep some
>equipment on with the SD8 I'd like to be able to make that tradeoff
>to help get me down (assuming IFR, in the soup).
You won't find a pilot's operating handbook anywhere that
has the crew flipping switches, taking measurements, and
crafting new plans based on real-time judgement calls
as an in-flight activity. When the main alternator fails,
craft a plan, test the plan, exercise the plan as necessary,
fly the airplane . . .
>So directly my question is....by swapping in the LED light on the
>highlighted circuit is it wired correctly?
That's not a "LOW VOLTS" warning light, it's an "ALT OFF"
annunciator.
>Since I couldn't find a Z-architecture that had this included, I
>used the B&C SD8 Power distribution diagram as reference on where to
>pull the light warning signal.
Ditch that light. I was under the impression that
you had some form of Low Volts warning in one or more
of your panel mounted accessories. If not, then you need
some independent, timely, and insistent notification
like our 9005 DIY project or Eric's LV warning light
module.
>Also can you please explain how the OVM-14 module works in tripping
>the light to come on....or point me to one of your articles that
>explains that better. I'm not clear on how this works.
See: Chapter 6 in the 'Connection.
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: Power for Checking Systems Out on the Ground |
I tried to order one of these power supplies, but the vendor in the example was
not willing to ship to North America.
I found what appears to be the same product, from anna758595 for $40 which included
shipment by mail. I received the product in three weeks, nicely packaged.
It is a little smaller than I imagined from the photos, which is nice. I haven't
powered it on yet, but I expect it works as advertised. I ended up buying
the 13.5V unit, since it can be adjusted upward to simulate battery charging
voltage, or down to 12V if I wish. The adjustment is easily accessed without
opening the case, tucked in with the terminal strip. Looks like a pretty decent
product at a very attractive price.
http://cgi.ebay.ca/13-5V-DC-25-8A-350W-Regulated-Switching-Power-Supply-/150471439243?pt=LH_DefaultDomain_0&hash=item2308cbf38b
Jeff Page
Dream Aircraft Tundra #10
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=334140#334140
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: latching relays |
>If every circuit has a CP and adding components to the CP reduces
>reliability, we can still increase reliability by adding a Redundant
>Circuit. The RC still has its own CP, but the reliability of the SYSTEM
>goes up.
Generally speaking, the adjective "critical" is reserved
for conditions that have a potential for (1) single
points of failure in (2) systems needed for comfortable
termination of flight where (3) no effort has been
made craft a failure tolerant system. When failure
tolerance has been achieved, no single failure is
"critical". In little airplanes maintained by the
competent observer/owner/operator, probability
of two potentially critical failures in any single
flight cycle (typically 4 hours max) is vanishingly
small.
Once a degree of failure tolerance is achieved, the
system integrator can begin to massage cost/performance
and parts reduction issues.
The successful program starts with design goals.
Goals that add/upgrade performance features (A-N
versus VOR versus TACAN versus GPS). To reduce cost
(less expensive parts with perhaps shorter service
lives are attractive). No doubt there are other
goals.
When I was heavily involved in new products design
and certification at Electro-Mech, one could look
forward to a pretty steady stream of hopeful sales
folks with a new electro-whizzy to show off. Some
were really amazing advances of the state of the
art . . . and would be considered for a new design.
But the $time$ required to modify and old design
made it unlikely that anything new gets a field
retrofit. In 40+ years, I've only worked three
programs that produced a fleet wide change-out
of hardware and two of those were under safety of
flight duress.
Even when I could tell the bright-eyed salesman
that he had a really nifty product, I had to
remind him that we'd beat him up on price, delivery,
cert documentation, and maybe . . . just maybe
we'd bless him with an order for 1000 parts spread
out over 10 years. Of course, that order would
get perpetually modified/canceled as our line rates
moved up and down with the stock market.
Aviation is one of the most demanding customers
yet the numbers of airplanes built every year
makes them a ho-hum target for the electro-
whizzy guys. Now, if you're selling rivets
or aluminum . . .
Okay, you've got this nifty latching contactor. I think
it's fairly obvious how it might be used in our
airplanes. The questions to be asked and answered
are (1) does this product 'fix' some nuisance of
maintenance, costs or sense of less-than-elegant
functionality?
Since (repeat after me) we DESIGN, CRAFT AND MAINTAIN
FAILURE TOLERANT SYSTEMS, reliability and criticality
are not part of the considerations. Only cost of
ownership and reasonably seamless integration
into the-best-we-know-how-to-do-today are the go/no-go
drivers.
Bob . . .
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: Bob Nuckolls - advice |
At 04:16 PM 3/16/2011, you wrote:
>Bob,
>
> I realise I should test for myself, but
> thought it might apply to others:
>
> I am using a DB25 female and male pair for
> quick disconnect to accommodate up to #18 wire
> runs for future circuits in my instrument
> panel. [The whole panel OR each sub-panel is meant to be dismountable].
>
> Since it will hold up to 12 + and ' runs, I
> measured the male pins at 0.04 inches in
> diameter from the pack of 100, labelled as
> `S604P=92. These are solid, not stamped pins and sockets.
>
> Can I consider these to carry a constant 4
> amps if not bundled tightly together? AND could
> I parallel a set of three to carry a constant 10A in similar
circumstances?
>
> I would like to know I=92m operating in
> a`conservative=92 milieu and don=92t plan to run
> cfuture equipment at greater than 10A.
That works. When I qualified paralleled d-sub pins
onto this vehicle
http://aeroelectric.com/Pictures/Misc/GQM_1st_Ops_Flight.jpg
I had to suffer the indignities of 70C environment at
full electrical loads. I de-rated the pins to 3A, paralleled
6 pins and handled three 20A input output pathways
on this solid state relay box.
http://aeroelectric.com/Pictures/Misc/GQM_Power_Dist.jpg
So your suggestion of 3 pins to handle 10A is
as conservative that which flies at Mach 3
and 15 feet off the water. Things get really
warm on the launch stand . . . and warmer still
in flight through dense air.
Just keep your airplane below M3 and I think
you'll be just fine. I presume you understand
the necessity for 'ballasting' resistors in the
form of 12" of 22AWG in each pin path?
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: | Re: Bob nuckolls - advice 2 |
At 05:33 PM 3/16/2011, you wrote:
>Further to my previous:
>
>A measured pin diameter is 0.04 inches, radius
>is 0.02=94, area is (0.02x0.02)xpi = 0.00125663
>sq.in. x 645.16 = 0.8107319 sq.mm.
>
>This comes out between AWG20 and AWG18 ' call it AWG #19.
The pin diameter isn't much of a driver. It's localized
heating at the pin-spring interface inside the female
pin. 3A de-rating will give you VERY comfortable
performance.
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: | Re: Transient_voltage_suppression_diode failure |
At 06:44 PM 3/16/2011, you wrote:
>3/16/2011
>
>Hello Fellow Aeroelectric Listers, You may be interested in the
>attachment and the below information:
Interesting. I had a chance to review some power distribution
diagrams for Cirrus products several years ago . . . it
was about the time they were incorporating the SD-20
alternator into one or more models.
Many of their architecture decisions were, shall we say,
novel? It would be interesting to see the details of
the service bulletin . . . the wording in the notice
sounds like they 'sprinkled' transorbs around the system
with some notion that it was a good thing to do.
Any of you who have been on the List for 13 years or
so will remember some discussions about transorbs.
Several of our members were proponents of transorb
"sprinkling" . . . but without having a terribly
good notion of how these critters are rated and how
they behave.
http://www.aeroelectric.com/articles/spike.pdf
There's another transorb issue that popped up a few
years ago. It was centered on this critter:
http://www.aeroelectric.com/Mfgr_Data/Semiconductors/704-15k36t.pdf
Seems that somebody got the cool idea that you could
PARALLEL numerous smaller devices and come up with
an array good for soaking up lots of energy. This
sorta works and a few manufacturers managed to
qualify devices to this spec. But process control
for having tightly matched devices to parallel
was critical.
I think Mooney had some of these critters "sprinkled"
in their airplanes and suffered some smokey events.
I discovered that situation when a hopeful supplier
to Hawker-Beech proposed a new starter-generator controller-
regulator. The thing had TWO of those monster transorbs
paralleled in the box. Seems that lightning issues in
composite airplanes drove the DO-160 qualification
stresses out to the moon.
Some of you may recall that I sketched a circuit
for adding a transorb to the main bus of an airplane
with the goal of standing off all evils.
http://aeroelectric.com/Pictures/Schematics/SpikeTrap.gif
The idea was that if something evil came along, the
transorb would catch it . . . that's what transorbs
do. But if it were so severe as to trigger transorbicide
(transorbs do that too), then the fuse would blow and
you would get an indicator light.
In any case, transorbs are quite helpful for getting
a black box to pass DO-160 + lightning tests. But as
soon as you see these critters scattered around an
airplane's electrical system, well . . . 'nuf said.
What was it somebody said about latching contactors
. . . "a solution looking for a problem?"
Bob . . .
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: | Z-12 and Plasma II ignition |
I am building an RV-9A per Z-12 outline. The plane has one elctronic ignition
on the right going to the top cylinders and one Slick magneto on the Left side.
The manufacturer of the electronic ignition insists that the rather thin electrical
wire (shelded cable) be attached directly to the battery. I am questioning
the advisability of this unless a fuse or CB placed at the battery. Uncomfotable
with this hot wire entering the fuselage and being seperated from the battery
bus. If the fuse is on the engine side I feel less in control to replace
the fuse or reset the CB. Could not find any references on the this website.
Would appreciate your thoughts on this matter.
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: | Re: Power for Checking Systems Out on the Ground |
>I ended up buying the 13.5V unit, since it can be adjusted upward to
>simulate battery charging voltage, or down to 12V if I wish. The
>adjustment is easily accessed without opening the case, tucked in
>with the terminal strip. Looks like a pretty decent product at a
>very attractive price.
>
>http://cgi.ebay.ca/13-5V-DC-25-8A-350W-Regulated-Switching-Power-Supply-/150471439243?pt=LH_DefaultDomain_0&hash=item2308cbf38b
I used about a half dozen of various models in projects
over the last two years. Got two of them on the bench right
now. Just be careful when hooking these guys across batteries.
Some of these products don't like to be reverse powered when
their ac input power is removed. I use a fat schottky in
series with the output to prevent tug-o-war issues. This
means you might want to order the next higher voltage
next time . . . but there's one resistor you can change
inside that will boost the output if necessary.
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: | Current draw for lighting Buss |
Hi all,
I am wiring my panel. It includes a PMA 8000 audio panel, SL30, Garmin
430W and 327 transponder. Each has a pin to control the brightness on a
separate lighting buss. I was going to use B&C's dimmer circuit. What I can't
seem to find is what the current draw for lighting is likely to be. The
specific question is, which B&C dimmer do I need.
Anyone know the answer?
Regards,
Michael Wynn
RV 8 Wiring
San Ramon, CA
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! --
|