Today's Message Index:
----------------------
1. 06:02 AM - Re: Bus bars was Master/Starter Contactor (Charlie Kuss)
2. 06:13 AM - Shunts and loadmeters (bob rundle)
3. 06:44 AM - Re: Master/Starter Contactor connection (Matthew Brandes)
4. 06:49 AM - Re: Re: Internally regulated alternator OVP (Robert L. Nuckolls, III)
5. 07:25 AM - Re: Bus bars was Master/Starter Contactor (Robert L. Nuckolls, III)
6. 07:25 AM - Re: Re: Master/Starter Contactor connection (Robert L. Nuckolls, III)
7. 11:01 AM - Battery Help ()
8. 11:14 AM - Re: Battery Help (BobsV35B@aol.com)
9. 11:18 AM - Re: Battery Help (Mark R Steitle)
10. 12:23 PM - Transistors and Alternator OV ()
11. 12:25 PM - Re: Battery Help (Robert L. Nuckolls, III)
12. 01:24 PM - Re: Battery Help (Dj Merrill)
13. 02:39 PM - Re: Battery Help (Terry Watson)
14. 02:59 PM - Re: Battery Help (Harley)
15. 03:17 PM - Re: Master/Starter Contactor connection bar ()
16. 04:27 PM - Re: Battery Help (Terry Watson)
17. 04:53 PM - Re: Autozone alternators (Kevin Horton)
18. 04:59 PM - Warning light press-to-test circuitry (Neil K Clayton)
19. 05:36 PM - Re: Warning light press-to-test circuitry (Brett Ferrell)
20. 05:39 PM - Re: Warning light press-to-test circuitry (Robert McCallum)
21. 05:53 PM - Re: Warning light press-to-test circuitry (Richard E. Tasker)
22. 05:54 PM - Re: Warning light press-to-test circuitry (Richard E. Tasker)
23. 05:56 PM - Re: Warning light press-to-test circuitry (rv-9a-online)
24. 06:48 PM - Re: Warning light press-to-test circuitry (Tim Dawson-Townsend)
25. 09:02 PM - Re: Warning light press-to-test circuitry (rv-9a-online)
26. 10:19 PM - Re: Warning light press-to-test circuitry (tonybabb)
27. 10:47 PM - Re: Warning light press-to-test circuitry (hebeard@comcast.net)
Message 1
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| Subject: | Re: Bus bars was Master/Starter Contactor |
connection
--> AeroElectric-List message posted by: Charlie Kuss <chaztuna@adelphia.net> connection
At 08:38 PM 4/27/2005, you wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
><b.nuckolls@cox.net>
>
>At 03:54 PM 4/27/2005 -0500, you wrote:
>
> >--> AeroElectric-List message posted by: "Matthew Brandes"
> ><matthew@n523rv.com>
> >
> >Connected my starter and master contactor with a single piece of bus bar...
> >should I use two pieces?
>
> Don't know why you would need to. What are your concerns?
> We often "bus" multiple devices that would normally accept
> terminals for fat-wires.
>
> If I understand your question, the pictures below
> are illustrative of copper (or brass) straps used
> to connect adjacent terminals of high current
> carrying devices.
>
>http://www.aeroelectric.com/Pictures/DISKA09F.JPG
>http://www.aeroelectric.com/Pictures/DISKA11F.JPG
>http://www.aeroelectric.com/Pictures/DISKA12F.JPG
>
> Bob . . .
Bob,
I've made 3 short bus bars for the electrical system on my RV-8A. I have
access to a solder pot. Is it worth my time to "Tin" these bars prior to
installation?
Charlie Kuss
Message 2
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| Subject: | Shunts and loadmeters |
--> AeroElectric-List message posted by: "bob rundle" <bobrundle2@hotmail.com>
I'm just starting to build a RV7AQB. I have IO-360 engine with B&C 60 Amp
Alt and 8A stby alt.
I'm following Z-12 drawing for the most part. I have a few beginner
questions:
1. Are the shunts usually located in the engine compartment? I notice the
wiring from the starter solenoid to the shunt should be 6 inches or less.
2. Is the sole purpose of a shunt to permt the hookup of an ammeter?
3. In Z-12 there is an indication of 2 ammeters (same as loadmeter) being
hooked up. Is the practice to just use 1 ammeter and a switch to go from
main alt to stby alt?
I'm also planning on 1 left side magneto and right side plamsa III ignition.
I'm planning on using a keyed switch to turn on the mag and start the
engine, plus a separate switch for the ignition. Does this sound like a good
combination?
Thanks very much as I get started understanding the electrical system
better.
BobR
Message 3
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| Subject: | re: Master/Starter Contactor connection |
--> AeroElectric-List message posted by: "Matthew Brandes" <matthew@n523rv.com>
Bob,
My concern was doing it right. :-) This is a case of "he did it, maybe I
should too?".
Thanks, I'll leave it as it is. FWIW, here is a picture of it:
http://www.n523rv.com/finishing/Dsc01134.jpg
Matthew Brandes,
Van's RV-9A (Finish Kit)
#90569
<http://www.n523rv.com/> http://www.n523rv.com
EAA Chapter 1329 President
EAA Chapter 868 Web Editor
Message 4
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| Subject: | Re: Internally regulated alternator OVP |
protection
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
protection
>
>
>Gents that went over the head of 99% of the audience, including me.
>
>
>What I got from this is "If driver shorts", "how likely, I don't know", "I
>replaced
>transistors....shorted...in other (?) equip..."
>
>That is all good, but.what kind of short? What equip? what kind of
>transistor are
>we talking about?
A silicon junction transistor. It can be of any genre' PNP, NPN. Newer
designs will use MOSFET transistor, usually N-Fets for the lowest possible
on-resistance . . . but the clever designer can use P-Fets if he figures
an adequate way to get the heat out.
>We are talking about a catastrophic transistor failure. Right? Also it
>must fail in a
>very specific way. The transistor drives how much current flows to the
>field. The
>IC controls this transistor. The more current to the field, the higher the
>alternators
>output. So far so good.
Correct in a broad sense . . . specifically, modern regulator transistors
are used as switches, not valves. They are either ON or they are OFF. In
and ON state, current through the device may be high, but the voltage
is low, hence low watts. In the OFF state, current is zero while voltage
is high, also low watts. Linear control is emulated by controlling the
ON/OFF ratio at some frequency, 200-1000 Hz.
> Normally the IC senses voltage and if there is over voltage
>it tells the drive transistor to shut down, but in this scenario the
>transistor fails in
>such a way the IC is not in control of it. In this scenario there is no
>fuse/current
>limiting device also in the picture in the event this happens.
Correct.
>The IC is watching the transistor and sensing currents thru out the
>alternator. The
>logic should detect an impending transistor melt down (short). Do
>transistors just
>melt down to a dead short between the drain and source?
Yup, they do that or they get the gate punched through causing it
to loose control of the current flow through the device.
> I have not plowed thru
>the whole 20 page document yet but page one has a good diagram and page 14,
>par: Field Coil Drive Device Protection, Drive Device = transistor.
>
>http://www.freescale.com/files/analog/doc/data_sheet/MC33099.pdf
Correct. The data for this chip is very well presented which
is good for marketing the device.
>The proposed scenarios is a catastrophic instantaneous failure of the
>transistor
>resulting in a loop where the alternator drives it self right up to the
>rails. The
>transistor (FET) must not only fail it must fail in a mode where
>the (drain) and
>(source) short. Transistor control (gate) provided by the IC is not
>effective. We
>have a real melt down. Also we are going to assume there is no other internal
>current limiting or fuse backup in the loop to protect from this runaway
>loop, if
>the transistor melts-down in this very specific way. The ND diagram I have
>does
>show a fuse or current limiter in the loop. How it exactly works I cant
>tell you?
Yup, you got it.
>The IC normally will shut the current off to the transistor (gate) if it
>senses a
>pending overload or shorted output transistor by comparing the response of
>the
>transistor to control input.
Where in the narrative do we find a feature that "senses impending
overload"?
> In the above failure the IC short/overload protection
>control of the transistors has no affect, full melt down is already in
>effect. This
>sudden catastrophic melt down might be very rare. I am thinking a common
>failure would be just an open failure, not a short.
Most transistor failures are over temperature induced which drives
the core temperature well above the 175C limit (for most devices)
and it does indeed become a solid blob of short. If the transistor
were subject to extraordinary currents (hard fault due to shorts
in field winding . . . it MIGHT exceed the bond-wire limits on
the transistor and fail it open . . . but this is very rare compared
to incidences of fail shorted.
> Also many transistors short to
>the (gate), meaning it will stop current from running thru it (drain to
>source).
>So what is Bob and Chris saying? What I get out of it is a rare transistor
>failure will fail dead short, not open. The IC's controls the alternator
>(field), thru
>that transistor will not catch it in time and all control lost. That is a
>lot of bad things
>to one component, but possible?
I didn't see that the IC knows anything about impending failures
and yes, you have correctly deduced the failure mode being discussed.
> Dont know. I am not saying can't happen, just
>that it sounds unlikely with the reliability of transistors and the smarts
>of IC
>protection are pretty good
Don't think it has a thing to do with IC smarts.
>(WARNING: EE types dont read the following, your head will explode. )
>I think some basics are in order. I promise its not too technical, because
>I dont
>know that much.
>
>Transistors are real reliable. The kind in the new alternators, field effect
>transistors, (FET or MOSFET), are very reliable. Also the way the VR
>controls the
>FET produces much less heat than older designs. What the industry says about
>these transistors is what you already know from the reliability of your
>TV, they
>rarely fail in short. The topic of how transistors fail is a subject for a
>PHD. The
>field-effect transistor is a very important type of transistor developed
>after the
>junction transistor. It draws virtually no power from an input signal,
>overcoming a
>major disadvantage of the junction transistor. You have much less heat
>with a FET
>than older designs using junction transistors. They are faster acting
>which allows
>them to be controlled with pulse width modulation, PWM. This means the
>controlling
>current is turned on/off very fast, and the width of the pulses is varied
>to control
>The transistors output. Way more efficient and cooler.
>
>
>Keeping the transistor cool is important; that is why they have heat sinks
>attached.
>Even though the FET runs real cool, a heat sink gets rid of heat and adds
>reliability.
>(Look at a ND alternator, you will see the cooling fins. Not all internal
>VR have this.)
Your not wrong my friend . . . but you're talking about the ideal world
where
every user of this technology has the skill, integrity and marketing goals
to maximize the POTENTIAL you've identified for reliable operation.
>=================================================
>
> >>If a separate external OVP device fails to work when it should then we
> >>have two separate devices failing simultaneously which is pretty rare.
> >>We can't test the functionality of an OVP internal to an alternator but
> >>we can test the separate OVP device if we so desire.
> >
>
> >Dead-on . . .
>
>
>Agree, multi failures are rare, and that applies to internal regulators
>also. The
>trans melt I understand and I guess you could have a IC failure but still
>think
>this is in the rare range. The IC has its own fault protection, in other
>words the
>"chip" in the chip is watching the shop. The specific transistor failure
>that the
>IC voltage regulator cant control or "predict" is also got to be rare.
>What about
>the secondary fuse in some internal VR alternators.
I have seen this one time . . . in an old Mitsubishi design I think.
They incorporated the fuse/zener ov protection similar to that found
in some early American Aviation/Grumman products. A secondary, independent
way to overcome loss of the pass transistor. Neat idea. If EVERYONE used
this form of OV PROTECTION in their products, it would be a very good
thing for airplane builders. But alas, I don't believe it is common, in
fact I'm sure it's not common an perhaps non-existent in current production
>CERTIFICATION ANYONE?
>
>A company called Plane-Power in Texas is in the process of certifying PMA
>replacement alternators based on Nippondenso alternators. They will offer
>internal
>and external voltage regulated versions. The certified versions will
>replace existing
>systems with external regulators, therefore they will also do the same.
>For the
>experimental market, in the next 2 months, they will have kits for $400, with
>brackets, both internal and external regulated. If you buy the external
>regulated
>model it will not come with a regulator. What about the internal VR
>version. As I
>understood it from Steve at plane-power said they modify the stock VR and
>add an
>internal crow-bar on the condition wire. I confirmed the condition wire was
>not a field wire and was the IGN wire (also known as: sense wire or on/off
>wire). I know that this approach is not advocated by Bob N. If that is a good
>approach than we could we just add the OV crow-bar on the breaker of an
>internal
>regulated alternator just like an external regulator? It would not help
>if your field
>driver transistor was dead short, as described above? However I am
>sticking to
>my guns, and will not be adding any extra OV protection to my ND
>alternator at
>this time. Yea for me.
The supplier you've cited has recognized and accepted the task
of designing, investigating failure modes and doing the testing
to show minimum levels of reliability . . . usually numbers in
the 10 to the minus 6 or better failure rates. He is also
going to have to sign up for CONFIGURATION control that says every
product he sells is not compromised by any changes in design that
are not proven equal to or better than the original certification
basis.
<snip>
>The fastest way to turn off an over voltage exist inside a modern
>alternator. Not
>with standing the melted shorted transistor scenario above, the internal OV
>protection will react very fast. So fast the buss may never see the OV.
>The crow
>bar method does have to wait for the buss to see the OV first (along with
>radios)
>and than wait to pop the CB, which may take a fraction of a second. How much
>abuse your radio can take.
>
>
>The auto industry cant stand over voltage or transient voltage any better
>than your
>avionics, may be even less (air bag, engine, transmission, anti-lock
>computers, gps,
>stereos). Bob N. says we need not bother with a master switch and turning off
>radios for start, which I understand. This is because modern radios have
>their own
>protection, but I have a master switch I am ashamed to say. Sorry Bob. It
>makes me
>feel better. Unless you really know how resilient your avionics are (like
>the icom
>A200, which I have) its prudent to take precautions as you see fit, as Bob
>says. The
>same with OV protection on top of internal regulated alternators. If you
>feel you
>must add the OV protection, do it. Chances are it will never be needed,
>you hope.
>Worst case scenario is it accidentally trips and causes your alternator
>some grief,
>but your radios should be safe.
>
>Bottom line you have to have a transistor fail. It must not only fail, but
>fail in a
>specific way. In this mode how much current can flow thru it with out just
>opening
>and basically acting as a fuse? Is the IC capable of proactively
>preventing it failing
>in the first place, thru good control and logic? What about other internal
>fuses?
If there were secondary, independent ov management, the guy doing this
certification task will find it MUCH easier to do. Secondary, independent
ov management does not exist in the design we've just reviewed.
So, in light of the discussion above, let's you and I play the role
of OBAM aircraft QUALIFICATION ADVISORS. What do we tell the OBAM
aviation community at large about the suitability of ANY automotive
alternator? Without a doubt, if the alternator can be shown to
have features and reliability studies suited for certification in
the spam-can world, then one can select that SPECIFIC product
for use in an OBAM aircraft with confidence. What would you advise
me as publisher of recommendations . . . what should my DESIGN GOAL
be for incorporation of automotive technologies into the OBAM
aircraft? I can take the position that only certifiable designs
should be used -OR- assume that none are certifiable (and presently
they are not) and comfortable integration suggests a means for
secondary, independent control of the OV condition . . . hopefully
without opening the as-received alternator for internal modifications.
You have correctly deduced the failure modes and illuminated an effort
on the part of one individual to overcome design shortfalls
and provide the aviation community with a product of known
quality. I'll suggest the real value of this discussion is to
cite what is NOT illuminated . . . we're no better informed as
to the suitability of an generic as-received alternator when
virtually none of the qualities we seek during certification
are known to us nor will they be made available.
This has been the frustrating part of the discussion. Those
who worship at the altars of any product claiming to offer modern
automotive reliability overlook the fact that ANYONE can start a church
based on any ideas . . . or none at all. While Plane-Power
seeks to be the true religion, we'll all expect and probably
receive a data dump of the simple-ideas that make their product
worthy of respect and acceptance. The little corner parts
stores or local junk yards will offer us a pew to occupy
and appreciate anything we'll throw in the plate when it's
passed . . . but ideas will not be forthcoming. The alternator
they sell you MIGHT be just as good as Plane=Power's . . .
but probably not. Without knowing the specifics, what
can I or anyone else offer in the way of considered advice?
Bob . . .
Message 5
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| Subject: | Re: Bus bars was Master/Starter Contactor |
connection
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
connection
At 08:49 AM 4/28/2005 -0400, you wrote:
>--> AeroElectric-List message posted by: Charlie Kuss
><chaztuna@adelphia.net> connection
>
>At 08:38 PM 4/27/2005, you wrote:
> >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> ><b.nuckolls@cox.net>
> >
> >At 03:54 PM 4/27/2005 -0500, you wrote:
> >
> > >--> AeroElectric-List message posted by: "Matthew Brandes"
> > ><matthew@n523rv.com>
> > >
> > >Connected my starter and master contactor with a single piece of bus
> bar...
> > >should I use two pieces?
> >
> > Don't know why you would need to. What are your concerns?
> > We often "bus" multiple devices that would normally accept
> > terminals for fat-wires.
> >
> > If I understand your question, the pictures below
> > are illustrative of copper (or brass) straps used
> > to connect adjacent terminals of high current
> > carrying devices.
> >
> >http://www.aeroelectric.com/Pictures/DISKA09F.JPG
> >http://www.aeroelectric.com/Pictures/DISKA11F.JPG
> >http://www.aeroelectric.com/Pictures/DISKA12F.JPG
> >
> > Bob . . .
>
>Bob,
> I've made 3 short bus bars for the electrical system on my RV-8A. I have
>access to a solder pot. Is it worth my time to "Tin" these bars prior to
>installation?
Adding a third alloy in the joint MIGHT have some benefits
in terms of reducing electrolytic corrosion . . . but if
your joints are gas-tight, then dissimilar metals are not
a big issue. FLATNESS of interfacing surfaces and PRESSURE
are keys to longevity. Adding more "stuff" in the joint
only raises questions as to flatness. I'd clean 'em up
bright, bolt 'em tight and truck on . . .
Bob . . .
Message 6
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| Subject: | Re: re: Master/Starter Contactor connection |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
At 08:43 AM 4/28/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: "Matthew Brandes"
><matthew@n523rv.com>
>
>Bob,
>
>My concern was doing it right. :-) This is a case of "he did it, maybe I
>should too?".
>
>Thanks, I'll leave it as it is. FWIW, here is a picture of it:
>http://www.n523rv.com/finishing/Dsc01134.jpg
you done good
Bob . . .
Message 7
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--> AeroElectric-List message posted by: <bakerocb@cox.net>
4/28/2005
Hello Fellow Aero-Electricers, Yesterday I was involved in an event where
our two primary VHF communication radios in a C-172 failed** while airborne
and we could receive, but not transmit anything but carrier. This almost
stranded us outside the Washington DC ADIZ. Fortunately the airplane's owner
had a handheld Garmin GPS Comm with him and after a bit of fumbling we got
to enter the ADIZ and land at homefield.
The Garmin handheld was being powered by an adapter cable plugged into the
airplane's cigarette lighter socket. The NiCad battery for the handheld was
useless even though it had been charged the night before -- it is an old
battery and may not have been able to take and hold a charge.
I later realized that if we had had an electrical failure in the airplane
that would have removed our source of electrical power from the cigarette
lighter socket that we would have been without any means of communication.##
So what I am looking for is a battery case with the following
characteristics:
1) Small light weight plastic.
2) Holds enough AA batteries to put out about 12 volts for a relatively
short period of time at a relatively light load.
3) Includes a cigarette lighter receptacle that one could plug an adapter
cable into for powering 12 volt accessories like a hand held radio or GPS.
I thought that surely something like this must exist, but after an hour or
so on the internet last night I could not find such a critter. My request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
**PS: I think the failure is due to over heating in the audio panel.
##PPS: I am aware in this circumstance that with no operating transponder we
would not be allowed into the Washington DC ADIZ, but that a different
story.
Message 8
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| Subject: | Re: Battery Help |
--> AeroElectric-List message posted by: BobsV35B@aol.com
In a message dated 4/28/2005 1:04:38 P.M. Central Standard Time,
bakerocb@cox.net writes:
I thought that surely something like this must exist, but after an hour or
so on the internet last night I could not find such a critter. My request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
Good Afternoon OC,
I carry an ancient ICOM IC-A3 transceiver in my emergency equipment pack.
It is powered by the optional battery pack that utilizes ten standard double A
batteries. I also carry a handheld GPS that is powered by double A
batteries. By carrying enough spare batteries to re-power both units I figure
I have
about as much back up communication and navigational capability as can be
had.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
Stearman N3977A
Brookeridge Airpark LL22
Downers Grove, IL 60516
630 985-8502
Message 9
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--> AeroElectric-List message posted by: "Mark R Steitle" <mark.steitle@austin.utexas.edu>
OC,
I did a search on "12v battery pack" on ebay and came up with many
items. This particular one comes with a carrying case, wall charger and
a cigarette lighter charger. See
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
615&rd=1#ebayphotohosting
Mark S.
So what I am looking for is a battery case with the following
characteristics:
1) Small light weight plastic.
2) Holds enough AA batteries to put out about 12 volts for a relatively
short period of time at a relatively light load.
3) Includes a cigarette lighter receptacle that one could plug an
adapter
cable into for powering 12 volt accessories like a hand held radio or
GPS.
I thought that surely something like this must exist, but after an hour
or
so on the internet last night I could not find such a critter. My
request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
Message 10
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| Subject: | Transistors and Alternator OV |
--> AeroElectric-List message posted by: <gmcjetpilot@yahoo.com>
Transistors and Alternator OV
It is true you can have a transistor "shorts, but not all transistors are the same,
not all applications are the same, and not all shorts are the same. The single
point argument against I-VR alternators is correct in theory, but there
are several factors that make this unlikely. You have one crankshaft in your plane.
They do fail but we trust they will not (unless you are flying one with
a known crank problem). This is why the transistor in you alternator (the single
point) should be very reliable. It is up to you to decide if this single "crankshaft"
(transistor) is good enough with out adding a second engine and flying
a twin.
Be careful drawing conclusions about transistor failures from other equipment.
How a transistor fails is dependent on how it is used. A stereo is not an alternator.
The transistor in a alternator may be running at 10% capacity Vs. some
hi-end stereo or power supply (depending on the kind of music you listen to)
near rated capacity. I don't know what is going thru the VR's field driver transistor,
but guess it is 2-3 amps or so. That is nothing, especially if you have
a heat sink. At 3 amps a heat sink is not even necessary, but adding one will
lower temps and increase reliability (of any transistor).
Transistors fail from getting to hot. Modern manufacturing makes transistors smaller,
more powerful and very reliable. Sudden shorts for no reason (like overload)
are rare. I will concede stuff happens. The electronic industry says transistors
are very reliable and any consumer of electronics will concur. TV's,
Microwave, cel phones work with out failure for 1000's of hours. Again you have
to be careful and compare apples to apples, but in general "semi-conductors"
are reliable if not abused. The how and why of failure is PHD land, but all we
need to know a transistor are as good as your crankshaft.
Type of transistors: The MOSFET (field effect transistor) is not a junction transistor.
How they fail is different. With that said, a MOSFET can fail (short)
in the way Bob says (drain to source). However it can fail in a multitude of
other ways, including just opening up. An "open" would cause the alternator to
just stop, a benign failure. How they are construction (type) and most important
how they are used determines reliability. That is why comparisons of transistors
in stereo is not truly valid, but it does point to the fact transistors
can fail. The MOSFET transistor in an alternator with PWM control is going to
be very efficient. I can take any electronic component and "blow it" by exceeding
its limitation. Like anything, operating with in the limits with margin will
keep safer.
This is one of the biggest things missed. THE transistor (driving the field) is
monitored by the IC chip. The IC is looking at the transistor's voltage in, out
and what it is being told to do. The IC looks at the transistors response,
shutting the door before a catastrophe transistor failure can happen. The IC knows
how that transistors should react and won't let it melt down (short). From
the reference I listed before, it is clear the IC circuit does monitor the transistor
for distress. Not only are transistors very reliable you have another
circuit monitoring it for one of the most common failures, a slow melt down.
Although I repeat a melt down at 2 amps is unlikely. Transistors at low power
are not just going to explode or short. Typically at low power they slowly degrade
in performance. That is what the IC detects, preventing any serious failure
by turning the alternator off. The IC is basically testing the transistor
continually. This is where the magic is if there is
any. The
IC will turn your alternator off and give you the "check alternator light". The
crow bar cant do this. Really transistors as old as the concept is, they are
still pretty amazing. Even more amazing is you can cram hundreds in a IC chip
and ask it to monitor, compare, check and regulate a system and it self.
A Denso VR assembly includes a sealed unit with heat sinks. As I said some alternators
use modules with no heat sink fins. No doubt the transistors in the other
brands are mounted in the module to transfer heat from the transistor to the
case, and in fact don't need a finned heat sink. A transistor has two ratings,
one with a heat sink and one with out. Not that the transistor in ND alternators
are more loaded, requiring a heat sink, they add them to improve reliability.
It cost more so some may not add it for cost savings or don't have the
room.
I suggest these units (ND) in their development were abused on test stands and
reliability was reached that was acceptable. I agree what is acceptable to an
automobile may not be acceptable to an aircraft. However as pointed out car electronics
also have serious need for a stable reliable voltage. I think what we
have now in the sate-of -art alternator with I-VR will be improved over the
next few years. Chance is these new modules, with even better protection and reliability,
will bolt into an existing alternator. For the quantum leap, I know
you could add redundant field control to an internal regulator. The cost is
not justified for the automotive industry at this time, but if a bunch of Lexus
or Mercedes-Benz start to fry electronics you will see this extra protection
sooner than later. Unfortunately it will be a new design, not an add on, beyond
the level of adding on a module.
Certification: I know it was said that an internal regulator could never be certified.
First being experimental is a badge of honor to me. Certification usually
involves telling the FAA "it is the same as this existing certified design".
The existing design can be bad, but as long as you are the same all is good.
If you cant say that, you try to prove that it cant fail or any failure is not
important and trivial to flight safety. Because GA airplanes have electrical
systems from the 50's or 60's (horrible), they use external regulators (and
add on OV protection sometimes). Trying to get the FAA to buy an IC circuit in
an internal regulator control may be swimming up stream. Does not mean it is
bad. Eventually it will happen if it has not already. If you installed dual internal
VR's with backup control of field power you might do it. Any takers; it
might cost a million dollars, but it will be great. To be fair to the FAA and
certification, not biting the hand that feed me, t
he
system works very well. This conservatism is what keeps the Gen public safe, but
it is at the cost of innovation and huge money to do anything different. That
is where experimental planes come in. May be not a revolution, just evolution.
Therefore I can feel good about using an alternator without the ass-on OV protection.
An IC has 100's of transistors. Some computer chips have millions or even hundreds
of millions of transistors. As I think it was said, ICs should be very reliable.
It is safe to say ICs that control things often have internal fault monitoring.
Forget about an almost impossible dual IC failure and Drive transistor
failure, the IC is very reliable. Any IC failure will no doubt be passive,
as the chip was designed. This self check logic is the same type that turns on
your cars warning lights (anti-lock, airbag, check engine).
Thanks for the great discussion, I agree that OV protection add ons are OK, and
should give you an extra level of comfort. However in my design goal, I am going
for the most simple system, light weight, ease of installation, that will
give me high reliability. Building and flying experimental planes, I can tell
you maintenance can suck the fun out of your flying. There will always be routine
and small items that are unavoidable, but the electrical system should be
one of the most reliable and maintenance free. Electrical gremlins suck. IN the
case of OV protection this is not a going to affect your reliability either
way, because it should be a rare event in any case. My only concern is a false
trip of a b-lead OV cutoff add-on may damage the I-VR or rectifier in alternator.
If you can assure high reliability, no false trips, you should have a very
reliable system. If the add-on system will add comfort to the builder/pilot,
it is good, but you have to stop with the add-ons at
some
point or you will end up with a twin-engine bi-plane. With or without will not
make much difference in most designs.
Thanks George
Message 11
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
At 01:17 PM 4/28/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: "Mark R Steitle"
><mark.steitle@austin.utexas.edu>
>
>OC,
>I did a search on "12v battery pack" on ebay and came up with many
>items. This particular one comes with a carrying case, wall charger and
>a cigarette lighter charger. See
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
>615&rd=1#ebayphotohosting
>
>Mark S.
>
>
>So what I am looking for is a battery case with the following
>characteristics:
>
>1) Small light weight plastic.
>
>2) Holds enough AA batteries to put out about 12 volts for a relatively
>short period of time at a relatively light load.
>
>3) Includes a cigarette lighter receptacle that one could plug an
>adapter
>cable into for powering 12 volt accessories like a hand held radio or
>GPS.
>
>I thought that surely something like this must exist, but after an hour
>or
>so on the internet last night I could not find such a critter. My
>request to
>you is: Does such a thing exist and how can I get one?
>
>Any other thoughts?
I try to avoid adding to the list of cockpit accessories
where ever possible. I fly with dual GPS310 receivers that
use AA batteries and my flight bag back-up is a JHP-520 that
gets new cells every year whether I turn it on or not. I put
new cells into both gps receivers outbound on a long trip
and new ones for the return. The DESIGN GOAL is to avoid
messing with batteries and battery boxes while in-flight . . .
ESPECIALLY in rough air or at night where risk of loosing
something on floor goes up.
Did an article on AA cells a few years ago at:
http://aeroelectric.com/articles/AA_Bat_Test.pdf which
was published in Sport Aviation. The driver for this
investigation was to see how to drive down battery
costs while elevating system reliability. I discovered
that the least expensive cells I could find were right
in the middle of industry average for energy contained
and the economics of running them until they died was
poor when compared with in-the-cockpit hazards.
I let my nieces and nephews have the used cells with
plenty of snort left in them and I never open a battery
box in flight. Would this modus operandi serve you
well also and eliminate the need for another flight-bag
accessory to guard against the dreaded dead-battery
syndrome?
Bob . . .
Message 12
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| Subject: | Re: Battery Help |
--> AeroElectric-List message posted by: Dj Merrill <deej@thayer.dartmouth.edu>
Mark R Steitle wrote:
> --> AeroElectric-List message posted by: "Mark R Steitle" <mark.steitle@austin.utexas.edu>
>
> OC,
> I did a search on "12v battery pack" on ebay and came up with many
> items. This particular one comes with a carrying case, wall charger and
> a cigarette lighter charger. See
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=1502&item=5769065
> 615&rd=1#ebayphotohosting
>
> Mark S.
You can also find something similar at Walmart in the
automotive section. Sometimes called emergency power packs,
or boost packs. They don't take AA batteries, but
they are rechargeable with a standard 12v cigarette plug.
You can also use it to start the engine if the main
battery goes dead... :-)
-Dj
--
Dj Merrill
Sportsman 2+2 Builder #7118
"TSA: Totally Screwing Aviation"
Message 13
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--> AeroElectric-List message posted by: "Terry Watson" <terry@tcwatson.com>
OC,
I have this gadget called a Coleman Powermate, 2" x 2-1/4" x 8" long, that
has a lighter plug on a cord about 18" long, and a lighter outlet in a
swivel head on the end of the main box. It has some nicad batteries sealed
inside. The idea is that you plug it in for awhile to charge it up, then
when you need power you can plug something into this unit. Or if your car
won't start, supposedly you can plug this thing in and it will over a few
minutes put some power back in the car's battery. It has an indicator light
on it.
I bought it at Costco maybe a year ago for maybe $20, but I haven't used it
other than play with it. It's been sitting on the shelf since then. I
think it's made for the application you are asking about.
The only additional information about model number on the case is 6969. I
think Coleman calls all of their electrical equipment Powermate. I couldn't
locate it on a quick Google search.
Terry
So what I am looking for is a battery case with the following
characteristics:
1) Small light weight plastic.
2) Holds enough AA batteries to put out about 12 volts for a relatively
short period of time at a relatively light load.
3) Includes a cigarette lighter receptacle that one could plug an adapter
cable into for powering 12 volt accessories like a hand held radio or GPS.
I thought that surely something like this must exist, but after an hour or
so on the internet last night I could not find such a critter. My request to
you is: Does such a thing exist and how can I get one?
Any other thoughts?
OC
Message 14
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| Subject: | Re: Battery Help |
--> AeroElectric-List message posted by: Harley <harley@agelesswings.com>
Evening, Terry...
Not sure where you got the 6969 from, but I believe that what you are
talking about is the Coleman Powermate Car Battery Booster. It's model
number is PMB8110
Searching on Google using that model number produces hundreds of places
selling it for anywhere from $20 to over $40.
Harley Dixon
Terry Watson wrote:
>--> AeroElectric-List message posted by: "Terry Watson" <terry@tcwatson.com>
>
>OC,
>
>I have this gadget called a Coleman Powermate, 2" x 2-1/4" x 8" long, that
>has a lighter plug on a cord about 18" long, and a lighter outlet in a
>swivel head on the end of the main box. It has some nicad batteries sealed
>inside. The idea is that you plug it in for awhile to charge it up, then
>when you need power you can plug something into this unit. Or if your car
>won't start, supposedly you can plug this thing in and it will over a few
>minutes put some power back in the car's battery. It has an indicator light
>on it.
>
>I bought it at Costco maybe a year ago for maybe $20, but I haven't used it
>other than play with it. It's been sitting on the shelf since then. I
>think it's made for the application you are asking about.
>
>The only additional information about model number on the case is 6969. I
>think Coleman calls all of their electrical equipment Powermate. I couldn't
>locate it on a quick Google search.
>
>Terry
>
>So what I am looking for is a battery case with the following
>characteristics:
>
>1) Small light weight plastic.
>
>2) Holds enough AA batteries to put out about 12 volts for a relatively
>short period of time at a relatively light load.
>
>3) Includes a cigarette lighter receptacle that one could plug an adapter
>cable into for powering 12 volt accessories like a hand held radio or GPS.
>
>I thought that surely something like this must exist, but after an hour or
>so on the internet last night I could not find such a critter. My request to
>
>you is: Does such a thing exist and how can I get one?
>
>Any other thoughts?
>
>OC
>
>
>
>
Message 15
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| Subject: | Re: Master/Starter Contactor connection bar |
--> AeroElectric-List message posted by: <kbob@cox.net>
Mathew,
I did the exact thing you did...built a one bar strap to connect the relay. When
the RV plans show a 2 bar! Further checking into resistance and load carrying
of the copper bar eased my mind. Yes - I will loose a tiny bit of voltage
when cranking. But so will the terminal ends, the other starter wires, the contactor,
etc. It won't crank long enough to heat the bar up. So I just left
it.
Kelly Patterson
PHX, AZ
RV-6A N716K FWF & Wiring (finally!)
Time: 05:39:15 PM PST US
From: "Robert L. Nuckolls, III" <b.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Master/Starter Contactor connection
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
--> <b.nuckolls@cox.net>
At 03:54 PM 4/27/2005 -0500, you wrote:
>--> AeroElectric-List message posted by: "Matthew Brandes"
><matthew@n523rv.com>
>
>Connected my starter and master contactor with a single piece of bus
>bar... should I use two pieces?
Don't know why you would need to. What are your concerns?
We often "bus" multiple devices that would normally accept
terminals for fat-wires.
If I understand your question, the pictures below
are illustrative of copper (or brass) straps used
to connect adjacent terminals of high current
carrying devices.
http://www.aeroelectric.com/Pictures/DISKA09F.JPG
http://www.aeroelectric.com/Pictures/DISKA11F.JPG
http://www.aeroelectric.com/Pictures/DISKA12F.JPG
Bob . . .
Message 16
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--> AeroElectric-List message posted by: "Terry Watson" <terry@tcwatson.com>
Harley,
Yes, that's the gadget. Mine doesn't have a serial number or model number
anywhere, (except the 6969) but that's it.
Terry
Do not archive
Not sure where you got the 6969 from, but I believe that what you are
talking about is the Coleman Powermate Car Battery Booster. It's model
number is PMB8110
Searching on Google using that model number produces hundreds of places
selling it for anywhere from $20 to over $40.
Harley Dixon
Message 17
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| Subject: | Autozone alternators |
--> AeroElectric-List message posted by: Kevin Horton <khorton01@rogers.com>
>--> AeroElectric-List message posted by: "Hinde, Frank George
>(Corvallis)" <frank.hinde@hp.com>
>
>Wow...So I guess I'll fit the alternator and see if it dies?....Would
>you guys add the OVP as an external protection device just to be safe?
>
>What do you all think?
The risk of an overvoltage is low, but it is not zero. I have seen
more than one message on this list from people who experienced
overvoltage events. Only you can decide whether you are comfortable
with that risk, or whether you want to add overvoltage protection.
Adding overvoltage protection to an internally regulated alternator
can create new failure modes. There is some question about whether
the alternator B-lead contactor can be counted on to open in the
presence of an overvoltage.
For me, I would only risk using an internally regulated alternator if
my avionics didn't cost much. If I had invested more money in
avionics than I was prepared to lose, then I would spend the dollars
to get an externally regulated alternator with external overvoltage
protection. You don't necessarily have to spend the money to go with
B&C. There are recipes on the web which show how to modify some
automotive alternators to make them work with an external regulator
and overvoltage protection.
http://www.geocities.com/timrv6a/alternator.htm
How much will it cost you in money and time to replace your avionics
if they get toasted by an overvoltage?
How much will it cost you in money and time to add an external
regulator and overvoltage protection?
--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://www.kilohotel.com/rv8
Message 18
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aeroelectric-list@matronics.com
| Subject: | Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: Neil K Clayton <harvey4@earthlink.net>
I'm struggling with a wiring issue involving panel warning lights;
Each warning light is part of a circuit between it's associated sensor and
ground. The warning lamps always have 12v applied to them. When the sensor
triggers, it connects the lamp to ground and the bulb illuminates. Easy!
I want to be able to touch a press-to-test button to test if the warning
lamps (or diodes in my case) are in fact working.
This involves a 2nd circuit between the press-to-test button and the lamp.
The button clamps the lamp to ground and the lamp lights. Right?
But...are here are my questions;
1) To only use one press-to-test button, I need all the lamps connected to
it, and by inference, to each other. But this same connection will
illuminate ALL the lamps when one is triggered for real by it's sensor. How
do I isolate the lamp for it's "everyday" purpose, but connect it to the
others for testing?
2) Connecting a lamp to ground for test purposes might have all sorts of
secondary effects on the sensors down the line. How do I disconnect the
sensor while grounding the lamp for test, then re-connect everything again
for everyday running?
Am I complicating this? I suspect I am but I can't see the wood for the trees!
Thanks
Neil
Message 19
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| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: "Brett Ferrell" <bferrell@123mail.net>
Neil,
I did the same thing with my panel, I just installed some 276-1653 (the ones
I got were rated 3A) or similar in the "test" line to each lamp so that it's
"normal" function does not backfeed back to illuminate the other lamps. My
setup was slightly more complicated also because some of my lamps were
switched ground to illuminate and some were switched positive voltage.
Brett
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=276-1653
----- Original Message -----
From: "Neil K Clayton" <harvey4@earthlink.net>
<aeroelectric-list@matronics.com>
Subject: AeroElectric-List: Warning light press-to-test circuitry
> --> AeroElectric-List message posted by: Neil K Clayton
> <harvey4@earthlink.net>
>
> I'm struggling with a wiring issue involving panel warning lights;
>
> Each warning light is part of a circuit between it's associated sensor and
> ground. The warning lamps always have 12v applied to them. When the sensor
> triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
> I want to be able to touch a press-to-test button to test if the warning
> lamps (or diodes in my case) are in fact working.
>
> This involves a 2nd circuit between the press-to-test button and the lamp.
> The button clamps the lamp to ground and the lamp lights. Right?
>
> But...are here are my questions;
>
> 1) To only use one press-to-test button, I need all the lamps connected
> to
> it, and by inference, to each other. But this same connection will
> illuminate ALL the lamps when one is triggered for real by it's sensor.
> How
> do I isolate the lamp for it's "everyday" purpose, but connect it to the
> others for testing?
>
> 2) Connecting a lamp to ground for test purposes might have all sorts of
> secondary effects on the sensors down the line. How do I disconnect the
> sensor while grounding the lamp for test, then re-connect everything again
> for everyday running?
>
> Am I complicating this? I suspect I am but I can't see the wood for the
> trees!
>
> Thanks
> Neil
>
>
>
Message 20
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| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: Robert McCallum <robert.mccallum2@sympatico.ca>
Neil;
A handful of diodes will accomplish what you want. Connect the anode of
two diodes to each lamp where it originally went to the sensor. Connect
the cathode of one diode to the original sensor connection, connect the
cathode of all the remaining diodes (1 from each lamp) together and to
the push to test switch which you use to ground them all. Each light
then works normally on it's own and they all come on together when the
push to test grounds them. They do not interfere with each other nor do
you affect the sensor.
Bob McC
Neil K Clayton wrote:
>--> AeroElectric-List message posted by: Neil K Clayton <harvey4@earthlink.net>
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
Message 21
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| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
Use diodes. A set of two diodes for each lamp, anodes connected to the
ground end of the lamps (leave the 12V connected as is to the lamps).
Cathodes (typically indicated by a line on the cathode end of the diode)
of one of the diodes from each set connected to the switch and the other
side of the switch connected to ground. Cathode end of the other diode
of each set connected to the line that normally turns on the lamp.
Press the button and all lamps come on but the ground on the lamp is
isolated by the other diodes from the normal lamp actuator. Release the
button and all lamps work normally .
Dick Tasker
Neil K Clayton wrote:
>--> AeroElectric-List message posted by: Neil K Clayton <harvey4@earthlink.net>
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
--
----
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that a significant number of electrons may have been temporarily inconvenienced.
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Message 22
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| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
Oh, you can use a common garden variety 1N4001 (or one from that series)
for up to one amp lamps.
Dick Tasker
Neil K Clayton wrote:
>--> AeroElectric-List message posted by: Neil K Clayton <harvey4@earthlink.net>
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
--
----
Please Note:
No trees were destroyed in the sending of this message. We do concede, however,
that a significant number of electrons may have been temporarily inconvenienced.
----
Message 23
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| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: rv-9a-online <rv-9a-online@telus.net>
Neil, you need a simple diode isolation circuit. Rather than describe
the circuit in detail, please go to
http://www3.telus.net/aviation/vx
and look for the IL-4A datasheet.
In the datasheet, you will see a schematic for the circuit and some
application notes. If you can't determine what's what, let me know
on-list and I'll put together some simpler information. Based on this,
you can wire up your circuit, or you can get an IL-4A that will do it
all for you.
The IL-4A senses ground-switched, +12V switched and reversing inputs
(flap motors, gear motors etc), provides push-to-test capability and
dimming capability for night operations.
Vern Little
RV-9A
Neil K Clayton wrote:
>--> AeroElectric-List message posted by: Neil K Clayton <harvey4@earthlink.net>
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
Message 24
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|
| Subject: | Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: "Tim Dawson-Townsend" <Tdawson@Avidyne.com>
Given the reliability of LEDs, you could probably get away without a press-to-test
. . .
TDT
________________________________
From: owner-aeroelectric-list-server@matronics.com on behalf of Neil K Clayton
Subject: AeroElectric-List: Warning light press-to-test circuitry
--> AeroElectric-List message posted by: Neil K Clayton <harvey4@earthlink.net>
I'm struggling with a wiring issue involving panel warning lights;
Each warning light is part of a circuit between it's associated sensor and
ground. The warning lamps always have 12v applied to them. When the sensor
triggers, it connects the lamp to ground and the bulb illuminates. Easy!
I want to be able to touch a press-to-test button to test if the warning
lamps (or diodes in my case) are in fact working.
This involves a 2nd circuit between the press-to-test button and the lamp.
The button clamps the lamp to ground and the lamp lights. Right?
But...are here are my questions;
1) To only use one press-to-test button, I need all the lamps connected to
it, and by inference, to each other. But this same connection will
illuminate ALL the lamps when one is triggered for real by it's sensor. How
do I isolate the lamp for it's "everyday" purpose, but connect it to the
others for testing?
2) Connecting a lamp to ground for test purposes might have all sorts of
secondary effects on the sensors down the line. How do I disconnect the
sensor while grounding the lamp for test, then re-connect everything again
for everyday running?
Am I complicating this? I suspect I am but I can't see the wood for the trees!
Thanks
Neil
Message 25
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| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: rv-9a-online <rv-9a-online@telus.net>
Two other functions of press-to-test:
Test the dimmer level for night time operation. It's very important
that the warning lights be visible at night (dimmer not too low).
Test the circuit breaker/fuse that drives the warning lamp circuits.
By the way... LED's fail mostly due to mechanical reasons (lead stress),
but they do fail.
Vern Little
Tim Dawson-Townsend wrote:
>--> AeroElectric-List message posted by: "Tim Dawson-Townsend" <Tdawson@Avidyne.com>
>
>
>Given the reliability of LEDs, you could probably get away without a press-to-test
. . .
>
>TDT
>
>
>________________________________
>
>From: owner-aeroelectric-list-server@matronics.com on behalf of Neil K Clayton
>To: canard-aviators@yahoogroups.com; Cozy_Builders@mailman.qth.net; aeroelectric-list@matronics.com
>Subject: AeroElectric-List: Warning light press-to-test circuitry
>
>
>--> AeroElectric-List message posted by: Neil K Clayton <harvey4@earthlink.net>
>
>I'm struggling with a wiring issue involving panel warning lights;
>
>Each warning light is part of a circuit between it's associated sensor and
>ground. The warning lamps always have 12v applied to them. When the sensor
>triggers, it connects the lamp to ground and the bulb illuminates. Easy!
>
>I want to be able to touch a press-to-test button to test if the warning
>lamps (or diodes in my case) are in fact working.
>
>This involves a 2nd circuit between the press-to-test button and the lamp.
>The button clamps the lamp to ground and the lamp lights. Right?
>
>But...are here are my questions;
>
>1) To only use one press-to-test button, I need all the lamps connected to
>it, and by inference, to each other. But this same connection will
>illuminate ALL the lamps when one is triggered for real by it's sensor. How
>do I isolate the lamp for it's "everyday" purpose, but connect it to the
>others for testing?
>
>2) Connecting a lamp to ground for test purposes might have all sorts of
>secondary effects on the sensors down the line. How do I disconnect the
>sensor while grounding the lamp for test, then re-connect everything again
>for everyday running?
>
>Am I complicating this? I suspect I am but I can't see the wood for the trees!
>
>Thanks
>Neil
>
>
>
>
Message 26
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| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: "tonybabb" <tonybabb@alejandra.net>
I'm electrically challenged so sorry if this is a dumb question but ....why
two diodes? I can see why you'd want a diode between the Push-to-test switch
and the lamp (because all the lamps would be connected together and you
don't want one turning on the others) but why another diode between the lamp
and whatever normally grounds it.
Thanks,
Tony Velocity SEFG
62% done, 78% to go.
----- Original Message -----
From: "Richard E. Tasker" <retasker@optonline.net>
Subject: Re: AeroElectric-List: Warning light press-to-test circuitry
> --> AeroElectric-List message posted by: "Richard E. Tasker"
<retasker@optonline.net>
>
> Use diodes. A set of two diodes for each lamp, anodes connected to the
> ground end of the lamps (leave the 12V connected as is to the lamps).
> Cathodes (typically indicated by a line on the cathode end of the diode)
> of one of the diodes from each set connected to the switch and the other
> side of the switch connected to ground. Cathode end of the other diode
> of each set connected to the line that normally turns on the lamp.
>
> Press the button and all lamps come on but the ground on the lamp is
> isolated by the other diodes from the normal lamp actuator. Release the
> button and all lamps work normally .
>
> Dick Tasker
>
> Neil K Clayton wrote:
>
> >--> AeroElectric-List message posted by: Neil K Clayton
<harvey4@earthlink.net>
> >
> >I'm struggling with a wiring issue involving panel warning lights;
> >
> >Each warning light is part of a circuit between it's associated sensor
and
> >ground. The warning lamps always have 12v applied to them. When the
sensor
> >triggers, it connects the lamp to ground and the bulb illuminates. Easy!
> >
> >I want to be able to touch a press-to-test button to test if the warning
> >lamps (or diodes in my case) are in fact working.
> >
> >This involves a 2nd circuit between the press-to-test button and the
lamp.
> >The button clamps the lamp to ground and the lamp lights. Right?
> >
> >But...are here are my questions;
> >
> >1) To only use one press-to-test button, I need all the lamps connected
to
> >it, and by inference, to each other. But this same connection will
> >illuminate ALL the lamps when one is triggered for real by it's sensor.
How
> >do I isolate the lamp for it's "everyday" purpose, but connect it to the
> >others for testing?
> >
> >2) Connecting a lamp to ground for test purposes might have all sorts of
> >secondary effects on the sensors down the line. How do I disconnect the
> >sensor while grounding the lamp for test, then re-connect everything
again
> >for everyday running?
> >
> >Am I complicating this? I suspect I am but I can't see the wood for the
trees!
> >
> >Thanks
> >Neil
> >
> >
> >
> >
>
> --
> ----
> Please Note:
> No trees were destroyed in the sending of this message. We do concede,
however,
> that a significant number of electrons may have been temporarily
inconvenienced.
> ----
>
>
Message 27
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|
| Subject: | Re: Warning light press-to-test circuitry |
--> AeroElectric-List message posted by: hebeard@comcast.net
Neil,
There is downside to having a test switch which illuminates all the warning lights.
This happened to me.
When Boeing first introduced the 727, one of the gee-whiz features was such a test
switch which illuminated every warning light on the Flight Engineers panel.
On a customer demonstration flight my Flight Engineer proudly pushed this test
switch in flight and the entire panel was ablaze in warning lights. The fun
began when he released the switch and all the lights remained on. We had to abhort
the sales pitch and return for an uneventful landing.
I know it's impossible, but it happened. If you are worried about an LED failure,
then perhaps another diode could also fail.
Harley E.
Do not archive
<SCRIPT language=javascript>postamble();</SCRIPT>
Neil,
There is downside to having a test switch which illuminates all the warning lights.
This happened to me.
When Boeing first introduced the 727, one of the gee-whiz features was such a test
switch which illuminated every warning light on the Flight Engineers panel.
On a customer demonstration flight my Flight Engineer proudly pushed this test
switch in flight and the entire panel was ablaze in warning lights. The fun
began when he released the switch and all the lights remained on.We had to abhort
the sales pitch and return for an uneventful landing.
I know it's impossible, but it happened. If you are worried about an LED failure,
then perhaps another diode could also fail.
Harley E.
Do not archive
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