Today's Message Index:
----------------------
1. 04:43 AM - Re: Optical Switch? (jhausch)
2. 05:23 AM - hello aeroelectric-list@matronics.com (Rodney Dunham)
3. 08:35 AM - Toyota (denso) alternator (Janet Amtmann)
4. 08:35 AM - Re: Re: Halogen bulbs with wig wag circuitry....failure mode (Robert L. Nuckolls, III)
5. 09:11 AM - Lithium batteries (Robert L. Nuckolls, III)
6. 09:16 AM - Re: hello aeroelectric-list@matronics.com (HIGH RISK) (Robert L. Nuckolls, III)
7. 09:31 AM - Re: Toyota (denso) alternator (Robert L. Nuckolls, III)
8. 09:39 AM - Re: Toyota (denso) alternator (OOPS) (Robert L. Nuckolls, III)
9. 09:43 AM - Re: Optical Switch? (jonlaury)
10. 10:38 AM - Re: Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd)
11. 12:51 PM - Needed Grimes Position Light Parts (Jerald Folkerts)
12. 12:55 PM - Re: Re: Halogen bulbs with wig wag circuitry....failure mode (Robert L. Nuckolls, III)
13. 06:22 PM - Re: Re: Optical Switch? (Bob McCallum)
14. 07:24 PM - Re: Re: Lithium Batteries? (Noel Loveys)
15. 07:50 PM - Re: Electric aircraft issues (Robert L. Nuckolls, III)
16. 07:57 PM - Re: Re: Electric aircraft issues (Robert L. Nuckolls, III)
17. 08:09 PM - Re: Re: Lithium Batteries? (Robert L. Nuckolls, III)
Message 1
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Subject: | Re: Optical Switch? |
jonlaury wrote:
> I need a switch that activates when something moves in front of a sensor. This
is not an aviation application. But I'm sure that someone on the list can save
me having to decipher all the offerings on Digi-key.
>
> I'm envisioning something similar to a garage door opener saftey beam/switch,
but way smaller, to operate on 12 vdc, for detection of material in a machine
process.
>
> Thanks for any help,
> John
John,
Bob is right on the mark. It sounds like he and I both make our living in the
factory automation world. If you just need one photo eye, I may have an old
demo unit I can send you or sell cheaply* Since you said this was for a machine
I am a little surprised you need 12v since most machines use 24v, but most
industrial dc sensors do run on 10-30vdc.
I am in a meeting from 8-12 central time today, but could discuss your application
with you this afternoon. Email either of us and we should be able to get
you sorted out straightaway.
I forget which email address I have tied to this list, so use jimhausch (at symbol)
gmail (dot) com
*cheap is a relative term...simple industrial sensors can sell from 10 to 100 bucks.
Folks with a knowledge of circuitry (like folks who might hang out here
:) ) know the base component costs for a simple photo eye can be had for pennies.
I will never forget a sales call I made where the customer wanted a simple
emitter-receiver pair to run on AC power. I told for single piece quantities,
including the cables he needed and offering the output rating he needed, might
cost $100. He said "what! I can buy a garage door opener that includes
two photo eyes for $100!"..... such is life :)
Jim
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=354980#354980
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hey aeroelectric-list@matronics.com wow this is crazy http://www.todayslocal10.com
Message 3
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Subject: | Toyota (denso) alternator |
I am using an internally regulated Toyota (Denso) alternator on my RV6. It
has the normal B+ charging lead and a plug with 3 spade connectors. One is
for the light, one for sense and one labeled IGN that supplies 12V to
energize the alternator before it starts running. Can anyone tell me what
happens to the output of this alternator if the IGN wire is disconnected
during flight (i.e. while the alternator is running)? I have my alternator
switch in this IGN line to take the alternator Off Line, but something tell
s
me this is not a good idea and that the alternator output may run away.
Regards, J=FCrgen Amtmann
Message 4
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Subject: | Re: Halogen bulbs with wig wag circuitry....failure |
mode
At 12:17 PM 10/12/2011, you wrote:
>
>Since this bulb failure issue was my original message and problem, I
>can add only another piece of mechanical evidence that may or may
>not have anything to do with the H7604 filament failures....
>1. Under magnification, both filaments separated not in the coil
>section, but, on the short straight ends just before their connection post.
>2. I do not know if the filaments (bulbs) were originally installed
>in the vertical or horizontal orientation. Rumor has it, that
>installing with the filaments vertically removes some of the
>mechanical stress from wing vibration and landing stresses.
>3. I have installed the new H7604's with the filaments in the
>vertical orientation and will report in the future if this seems to
>extend the bulb life.
Hmmmm . . . I'm suspicious of any 'benefit' for
orientation of filaments to increase resistance
to vibration stresses. Most materials exhibit a
thing called a stress-to-events-ratio (S/N ratio)
where a number of events at a particular stress
level are required to structurally fail the
material. Further, the S/N curve is generally
not linear. In other words, raising the stress
level by a factor of 3 does not necessarily
result in failure at 1/3rd the number of cycles.
It might drop to 1/4th the number of cycles.
Stress transients on landing are short duration
but very few in number compared hours of in-flight
stimulus.
Tungsten has a unique metallurgical property where
the metal transforms from a brittle to a ductile
state at a rather low temperature. I think it was
on the order 500F. In any case, it was below the
dull-red-glow temperature. In the chapter on
lighting in the 'Connection, I described two
techniques for keeping a filament warm when the
light was OFF. Maintaining the brittle filament
at or above it's brittle-to-ductile transition
temperature has a marked effect on the S/N ratio.
It would be a very interesting experiment to
try some form of keep-warm system on an airplane
that exhibits a high failure rate for tungsten
filament lamps.
Bob . . .
Message 5
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Subject: | Lithium batteries |
In the days since this topic was last discussed
here on the list, I've done a little research
into the number and nature of 'battery induced
fires' aboard aircraft.
This was one of several interesting documents
I ran across during the search . . .
http://safetravel.dot.gov/Action_Plan.pdf
I have yet to discover a description of a battery
fire involving a SYSTEM battery on the 'net. If
anyone runs across such a narrative, I'd be pleased
to have the link. The ramp fire on the Cessna is
the first incident I'm aware of and that information
was 'through the grapevine'. Industry focus has been
on the vast majority of battery fires where the
devices were either packaged for shipment as
cargo/baggage or in relatively light duty service
as a component of a personal electronic device in
passenger spaces.
The document I cited states that only 27%
of incidents studied involved lithium batteries.
The remainder were other technologies, lead-acid
being the most probable. The consensus for
root cause of battery fires trends toward
short circuits . . . which is not a technology
issue but a process issue.
This short study suggests that our deliberations
will not benefit from a study of battery fire
incidents in the wild. The study confirms what
we already knew. Batteries offer very high
concentrations of energy in small volumes.
Unintentional and uncontrolled release of that
energy poses risks. Lithium elevates those risks
by ADDING combustible materials to the potential
release of energy.
So as the experiments and discussion of our SYSTEM
batteries goes forward, let's keep those differences
in mind. Further, it is probable that a citation of most
battery fire incidents in the wild will add little or
no useful information to the conversation.
Bob . . .
Message 6
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At 12:19 AM 10/14/2011, you wrote:
>
>hey aeroelectric-list@matronics.com wow this is crazy
>http://www.todayslocal10.com
Rodney,
Has your email address been hijacked?
List-Members. Hitting on this link is HIGH RISK
not unlike the incident that visited the list
a few weeks ago.
Bob . . .
Message 7
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Subject: | Re: Toyota (denso) alternator |
At 10:30 AM 10/14/2011, you wrote:
I am using an internally regulated Toyota (Denso)
alternator on my RV6. It has the normal B+
charging lead and a plug with 3 spade
connectors. One is for the light, one for sense
and one labeled IGN that supplies 12V to energize
the alternator before it starts running. Can
anyone tell me what happens to the output of this
alternator if the IGN wire is disconnected during
flight (i.e. while the alternator is running)? I
have my alternator switch in this IGN line to
take the alternator Off Line, but something tells
me this is not a good idea and that the alternator output may run away.
Regards, Jrgen Amtmann
The risks of uncontrollable runaway for internally
regulated alternators is very low but not zero.
Commercial offerings of automotive conversions for
aircraft either modify the alternator for EXTERNAL
regulation and OV protection (a la B&C) or get
modified to accept external OV protection (a la
Plane-Power).
No doubt there are thousands of internally regulated
alternators flying without ov protection that have
never experienced a runaway failure . . . but there
have been a few . . . with predictable results.
The choice is yours.
Bob . . .
Message 8
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Subject: | Re: Toyota (denso) alternator (OOPS) |
At 10:30 AM 10/14/2011, you wrote:
I am using an internally regulated Toyota (Denso)
alternator on my RV6. It has the normal B+
charging lead and a plug with 3 spade
connectors. One is for the light, one for sense
and one labeled IGN that supplies 12V to energize
the alternator before it starts running. Can
anyone tell me what happens to the output of this
alternator if the IGN wire is disconnected during
flight (i.e. while the alternator is running)?
OOPS! I hit the 'send' button too soon.
Controlling power to the IGN lead will place the alternator
off/on-line while the engine is running. It's not
an unsafe or risky thing to do. However, there
are failures internal to the regulator that
cannot be controlled by the switched IGN lead.
Suggest you review the articles on ov protection
here:
http://tinyurl.com/3hj8gm2
I have my alternator switch in this IGN line to
take the alternator Off Line, but something tells
me this is not a good idea and that the alternator output may run away.
Regards, J=FCrgen Amtmann
The risks of uncontrollable runaway for internally
regulated alternators is very low but not zero.
Commercial offerings of automotive conversions for
aircraft either modify the alternator for EXTERNAL
regulation and OV protection (a la B&C) or get
modified to accept external OV protection (a la
Plane-Power).
No doubt there are thousands of internally regulated
alternators flying without ov protection that have
never experienced a runaway failure . . . but there
have been a few . . . with predictable results.
The choice is yours.
Bob . . .
Message 9
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Subject: | Re: Optical Switch? |
To All,
Thanks for your input/suggestions.
Here's more information to help narrow the choices.
The gap to be sensed is
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=355010#355010
Message 10
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Subject: | Re: Halogen bulbs with wig wag circuitry....failure |
mode
Bob,
You are always surprising me with your knowledge background. My grey matter
stores a lot and I have a degree in electronics, however, I learn constantly
from your inputs to all these problems and questions.
Funny, I did not know that the halogen environment still included tungsten
filaments. I was assuming, some other mixture of metal was the basis for
these brighter lamps.
You bring up an interesting option...to keep the lamp filaments in their
flexible or ductile stage while in any none use state. I wonder what level
of current would be needed for that in a 12 - 14 v. system. And, an option
would have to be planned in the case of an alternator failure to cut the
background lamp current. Thanks, David
______________________________________________________________
----- Original Message -----
From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
Subject: Re: AeroElectric-List: Re: Halogen bulbs with wig wag
circuitry....failure mode
>
> At 12:17 PM 10/12/2011, you wrote:
>>
>>Since this bulb failure issue was my original message and problem, I can
>>add only another piece of mechanical evidence that may or may not have
>>anything to do with the H7604 filament failures....
>>1. Under magnification, both filaments separated not in the coil section,
>>but, on the short straight ends just before their connection post.
>>2. I do not know if the filaments (bulbs) were originally installed in
>>the vertical or horizontal orientation. Rumor has it, that installing
>>with the filaments vertically removes some of the mechanical stress from
>>wing vibration and landing stresses.
>>3. I have installed the new H7604's with the filaments in the vertical
>>orientation and will report in the future if this seems to extend the bulb
>>life.
>
> Hmmmm . . . I'm suspicious of any 'benefit' for
> orientation of filaments to increase resistance
> to vibration stresses. Most materials exhibit a
> thing called a stress-to-events-ratio (S/N ratio)
> where a number of events at a particular stress
> level are required to structurally fail the
> material. Further, the S/N curve is generally
> not linear. In other words, raising the stress
> level by a factor of 3 does not necessarily
> result in failure at 1/3rd the number of cycles.
> It might drop to 1/4th the number of cycles.
> Stress transients on landing are short duration
> but very few in number compared hours of in-flight
> stimulus.
>
> Tungsten has a unique metallurgical property where
> the metal transforms from a brittle to a ductile
> state at a rather low temperature. I think it was
> on the order 500F. In any case, it was below the
> dull-red-glow temperature. In the chapter on
> lighting in the 'Connection, I described two
> techniques for keeping a filament warm when the
> light was OFF. Maintaining the brittle filament
> at or above it's brittle-to-ductile transition
> temperature has a marked effect on the S/N ratio.
>
> It would be a very interesting experiment to
> try some form of keep-warm system on an airplane
> that exhibits a high failure rate for tungsten
> filament lamps.
>
>
> Bob . . .
>
>
>
Message 11
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Subject: | Needed Grimes Position Light Parts |
At Sun-N-Fun this year, I purchased a used set of position/tail lights in
the tent. My plan was to use the PSA Enterprises LED replacement lenses for
a simple LED lighting system on my Murphy Super Rebel. When I got home, one
of the lights had no guts, i.e. the spring, phenolic washer, plastic washer,
wood spacer, and metal center pin. Before I hit the salvage yards, does
anyone have a single light or light parts laying around? I just need the
guts - WTB. I suppose I could machine the parts as well - probably not to
difficult other than time. Lesson learned, beware of parts in sealed bags.
Thanks,
Jerry Folkerts
SR2500 #093
www.mykitlog.com/jfolkerts
Message 12
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Subject: | Re: Halogen bulbs with wig wag circuitry....failure |
mode
>
>Funny, I did not know that the halogen environment still included
>tungsten filaments. I was assuming, some other mixture of metal was
>the basis for these brighter lamps.
It's my assumption that they're still tungsten.
A quick look at Wikipeda
http://en.wikipedia.org/wiki/Halogen_lamps
didn't suggest any 'new' materials.
You bring up an interesting option...to keep the lamp filaments
in their flexible or ductile stage while in any none use state. I
wonder what level of current would be needed for that in a 12 - 14 v. system.
The POWER needed is quite low but the current
is substantial due to the large positive temperature
coefficient of lamp resistance. I just took a couple
14v halogen lamps to the bench and was able to get
the first signs of visible light (tiny red glow) at
about 1.5 volts. However, the current draw was a
substantial portion of rated current at full voltage.
One example: A lamp I tested gave me first visible
light at 1.5V and 1.7A for a total of about 2.6W.
This lamp was rated at 55W at 14V or 3.9A.
This says that the resistor-diode technique described
in the 'Connection would be terribly inefficient. But
if you've got a fat alternator and some place to
let the heat dump out . . . the technique may be
practical . . . and low cost.
The obvious solution is to use a 2 t0 2.5v DC-DC
converter. There are a number of commercial off the
shelf products. Many such devices can be purchased
through the industrial surplus houses for a reasonable
price. Alternatively, you can do your own DC-DC buck
converter. There are a number of design tools
on the 'net that will assist in component selection.
The nice thing about it is that output ripple
voltage can be pretty high. Light bulbs don't care.
You WILL want to consider EMC filtering as these
devices operate in the 0.1 to 1.0 MHz range and
would be pretty noisy.
The fast-turn solution might be to use an LED
driver like the Buck Puck 2100 mA device
http://www.ledsupply.com/0a009-d-v-2100.php
throttled down through the dimming input to
get you a barely visible light output in a dark
hangar. EMC questions apply here too. The neat
thing about DC to DC conversion is efficiency.
Something like the Buck-Puck should be 85% efficient
or better. A 2.5 watt keep warm system for a 55w
lamp would only need 3W or so from the bus.
Another plus of the Buck Pucks is that they're
rated for up to 32 volts operating voltage.
PLENTY of headroom for observing DO-160 surge
requirements in a 14v system.
And, an option would have to be planned in the case of an alternator
failure to cut the background lamp current. Thanks,
You bet. Of course, things light landing lights
might drive from the main bus which would be down
during battery only ops anyhow. If you've got
battery left over on short final, then bring the
main bus back up and use the landing light.
The keepwarm circuit is a great mitigation
of inrush current too.
Bob . . .
Message 13
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Subject: | Re: Optical Switch? |
John;
Based on the new information you've supplied an Omron E3Z-T61 0.5M or
E3Z-T61A 0.5M should do the trick or you could go to a fiber optic series
such as the E3X-A11 or E3X-A41 which use a 2mm plastic fiber optic cable to
transmit the light beam allowing the actual sensor to be remotely mounted.
The T61 is an infrared sensor; the T61A is visible red light. These sensors
are NPN switching, if you need or desire PNP switching substitute an 8 for
the 6 in the part #
The E3X series are red visible light the A11 model is NPN the A41 model is
PNP
All of these sensors are through beam as you've requested. For the E3X
series you can use unterminated fiber as a substitute for the rather
expensive accessory fibers sold by Omron. I can send you several feet in the
mail free should you decide to go that route. Just PM me your address if you
wish some fiber.
Bob McC
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-
> server@matronics.com] On Behalf Of jonlaury
> Sent: Friday, October 14, 2011 12:40 PM
> To: aeroelectric-list@matronics.com
> Subject: AeroElectric-List: Re: Optical Switch?
>
>
> To All,
>
> Thanks for your input/suggestions.
> Here's more information to help narrow the choices.
>
> The gap to be sensed is
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=355010#355010
>
>
>
>
>
>
>
> _-
> ====================================================
> ======
> _-
> ====================================================
> ======
> _-
> ====================================================
> ======
> _-
> ====================================================
> ======
>
>
Message 14
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Subject: | Re: Lithium Batteries? |
I've heard of much worse than this with a NiCad aircraft battery which
almost resulted in a Sikorsky S-92 being unceremoniously dumped off an oil
platform. Batteries are not always our friends.
Noel
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Eric M.
Jones
Sent: October 11, 2011 9:45 PM
Subject: AeroElectric-List: Re: Lithium Batteries?
<emjones@charter.net>
A few years ago I related to Bob N. my experience with a a couple 12V
carbon-zinc Eveready lantern battery that I used to power a Telex intercom
(which usually plugged into the rarely-connected cigar lighter). The first
battery was found dead under mysterious circumstances (I was probably
lucky). The replacement battery, upon shutting down the aircraft was too hot
to touch and I grabbed it by the wires and tossed it out onto the asphalt.
It melted a dent in the ramp. It was smoking.
I surmised that the batteries had some internal crushing damage from rapid
descent, but perhaps they were damaged from voltage fed back from the
intercom. But I can't see how. The intercom was undamaged.
This whole thing remains a mystery, but I offer it as a clue regarding
batteries.
Batteries might need to have mechanics that withstand deformation by rapid
pressure changes.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones@charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=354739#354739
Message 15
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Subject: | Re: Electric aircraft issues |
Posted: Mon Oct 10, 2011 4:02 am
Bob:
I recall working a MU2 accident down in TX that
involved a ni-cad battery fire . . .
Glen: was that the one involving a runaway battery that severed the
pitch control system?
No . . . at least I don't think so. This airplane
used two sets of 24 volt ni-cads that were hooked
in series to get 48 volts to start the engines; then
reconnected in parallel for normal ops. My mentor, Ken
Razak asked me to look at the series-parallel switching
system as a potential root cause of the battery fire.
The pilot got the airplane down on the ground from about
10K onto the grass adjacent to a runway. All souls got
out and the fire crews were able to quickly put out
the fire.
Since the system was behaving normally for a departure
and climb to 10K there was little reason to suspect that
the series-parallel switching system was 'stuck' in an
abnormal condition. But given the paralleled generators
capable of putting many amps into those nice little light
weight batteries, it was far more likely that the battery
array suffered thermal runaway and went into self destruction.
This was the era of before-battery-overheat-monitors.
Some years later, a technician I hired to work with me
in the video business mentioned a burned airplane he helped
restore in Tx. Turns out it was the same MU-2,
Bob . . .
Message 16
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Subject: | Re: Electric aircraft issues |
Sun Oct 09, 2011 12:36 pm
Hi Bob
You mentioned: "The Shorai folks caution against an energetic
recharge of a deeply depleted battery."
This is not only true of a Lithium battery, but charging a discharged
lead acid battery with a high powered alternator that's trying to
maintain a constant voltage (just got aeroplane or car running from a
jump start) is not very easy on the battery.
How could one limit the charging amps going into the battery yet
still allow the alternator to carry any loads?
Ron P.
It's not terribly difficult. We've had generator
regulators that could not only limit the generator's
output current . . . but the can current-balance to
paralleled generators.
It would not be difficult to design a regulator that
would limit re-charge current to the battery. This would
call for a scheduled reduction of bus voltage while the
really beat battery catches it's breath. The voltage
would not be so depressed that it hampered normal system
operations . . . but such a regulator would have prevented
ni-cad fires and eliminated the need to add the battery overheat
monitor to ni-cad fitted airplanes.
Bob . . .
Message 17
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Subject: | Re: Lithium Batteries? |
At 09:20 PM 10/14/2011, you wrote:
>
>I've heard of much worse than this with a NiCad aircraft battery which
>almost resulted in a Sikorsky S-92 being unceremoniously dumped off an oil
>platform. Batteries are not always our friends.
One could say the same thing about barrels
of gasoline, 400 h.p. engines in street machines,
or BD-5J airplanes.
When operated within their respective limits compatible
with the environment, they can seem quite benign
and spectacularly useful.
But in the wrong hands short of skill or knowledge,
they can prove quite hazardous. I was out on a field trip
with K. Razak many moons ago and had to slap out an
escalating source of smoke and bad smells from a pants
pocket. I'd tossed a handful of AA alkaline cells
into the pocket with a bunch of coins and a key-ring.
If those had been synthetic as opposed to good ol'
denim Dickies, I might still bear the "mark of Duracell"
on my thigh!
I did it in good company. Had lots of lawyers standing
around hoping we were going to do some good things
for them. I told them that hat-dance entertainment
was no extra charge. Now, if that had been a
lithium cell . . .
Bob . . .
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