Today's Message Index:
----------------------
1. 08:05 AM - Re: Master contactor temp? (Eric M. Jones)
2. 08:23 AM - Re: Re: Master contactor temp? (Roger)
3. 08:35 AM - Re: Re: Master contactor temp? (Charlie England)
4. 09:22 AM - Re: Master contactor temp? (Robert L. Nuckolls, III)
5. 09:38 AM - Re: Master contactor temp? (Robert L. Nuckolls, III)
6. 09:53 AM - Re: Master contactor temp? (Justin Jones)
7. 10:05 AM - Re: Master contactor temp? (Alec Myers)
8. 10:50 AM - Re: Master contactor temp? (Eric M. Jones)
9. 11:40 AM - Re: Re: do I need to change my capacitor (Robert L. Nuckolls, III)
10. 12:54 PM - FW: Re: Master contactor temp? (Roger)
11. 12:54 PM - Re: Re: Master contactor temp? (Robert L. Nuckolls, III)
12. 12:54 PM - Re: Master contactor temp? (donjohnston)
13. 06:52 PM - Re: FW: Re: Master contactor temp? (Robert L. Nuckolls, III)
14. 07:44 PM - Re: Re: Master contactor temp? (Alec Myers)
15. 08:25 PM - Re: Re: Master contactor temp? (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Master contactor temp? |
"Ambient" refers to the contactor temperature. But keep in mind that "ambient"
doesn't refer to the temperature someplace outside, but AT and ON the contactor
can.
The Type 70 would not specified to use at many airports and inside the cowls of
many airplane based on these numbers. 122 deg F is not very hot. It was hatter
than that in Phoenix a couple days ago, and Death Valley that would be a nice
day.
Furthermore the type to is G-position sensitive, vibration sensitive, not liquid
proof and has many undesireable characterists compared to other solutions.
As for my choice? I go with the Flaming River Battery Switch, or any of the several
electronic contactor offerings, unless your mission doesn't take you far
from home.
Factoid: No NASCAR vehicle uses a type-70 contactor.
Factoid: Very old Type-70's were made from far better stuff.
Please, can we do better than "hot to the touch"
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=457449#457449
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| Subject: | Re: Master contactor temp? |
"Ambient" refers to the contactor temperature
This is not true! The Ambient temperature is the temperature of the
air in the general vicinity of the subject device, not the temperature of
the device itself.
Roger
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| Subject: | Re: Master contactor temp? |
ambient
ambnt/
/adjective/
1.
*1*.
of or relating to the immediate surroundings of something.
"the liquid is stored at below ambient temperature"
Please, Eric; we can do better with our definitions.
;-)
On 6/26/2016 10:03 AM, Eric M. Jones wrote:
>
> "Ambient" refers to the contactor temperature. But keep in mind that "ambient"
doesn't refer to the temperature someplace outside, but AT and ON the contactor
can.
>
> The Type 70 would not specified to use at many airports and inside the cowls
of many airplane based on these numbers. 122 deg F is not very hot. It was hatter
than that in Phoenix a couple days ago, and Death Valley that would be a nice
day.
>
> Furthermore the type to is G-position sensitive, vibration sensitive, not liquid
proof and has many undesireable characterists compared to other solutions.
>
> As for my choice? I go with the Flaming River Battery Switch, or any of the several
electronic contactor offerings, unless your mission doesn't take you far
from home.
>
> Factoid: No NASCAR vehicle uses a type-70 contactor.
> Factoid: Very old Type-70's were made from far better stuff.
>
> Please, can we do better than "hot to the touch"
>
> --------
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge, MA 01550
> (508) 764-2072
> emjones(at)charter.net
>
Message 4
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| Subject: | Re: Master contactor temp? |
At 11:04 AM 6/25/2016, you wrote:
>I am not sure if it would work for a starter relay or not. One
>behavior I noticed is when I leave my LED instrument lights on and
>shut the battery off (this solid state relay) the LEDs will dim down
>while shutting off (like dimming them with a pwm). If I shut the
>LEDs off with their switch, they turn off instantly. Odd, but it
>doesn't seem to have any ill effects.
The solid state 'contactor' is a array
of field effect transistors controlled
by a variable voltage applied to their
'gates'. When used as a 'switch', on wants
them to be either 'on hard' or 'off hard'
like the behavior of contacts in relays
and switches . . . but depending on the
circuitry that drives the gates, the
transition time between ON and OFF states
may not be quite as fast as for metallic
contacts.
With solid state contactors, there is a much
longer intervale to achieve the same current
flow as an open sent of contacts and it's
most observable when controlling devices that
with activity at every low currents . . . like
an LED. In a dark room, an LED can produce
visible light with tens of micro-amps of current
flow.
Hence, what you've observed is an ordinary
circumstance that does not speak ill of the
contactor's performance. Airplanes with higher
levels of constant-on loads will drag the
bus down faster during contactor shut-down
make the behavior more like metallic contactors
but there's seldom a reason to make this a
design goal.
Bob . . .
Message 5
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| Subject: | Re: Master contactor temp? |
At 10:56 AM 6/25/2016, you wrote:
><jmjones2000@mindspring.com>
>
>They are $160. That's slightly more expensive than a good quality
>continuous duty relay like Skytec, but you only make the purchase
>one time. Cheap when talking about aircraft parts.
What place do the legacy metallic contactors
hold in the hierarchy of cost-of-ownership
issues. Where to they stand on the list of
risk drivers?
At every airplane factory I've worked at, there
were periodic meetings to identify, discuss and
mount mitigation programs for hardware problems
in the field. The vast majority posed little if
any increase in risk . . . only cost of ownership
and loss of company image with the customer.
I have never seen a metallic contactor on the
top-ten list . . . one of them made it to the
'gee, should we do something about this?' list.
http://www.aeroelectric.com/Pictures/Failures/6041_Contactor_Failure.jpg
The answer was, "No, while perhaps spectacular
there was nothing beyond a cost-of-ownership
issue for less than a dozen aircraft in a fleet
of hundreds over ten years. None of the failures were
even in-warranty.
So what's the return on investment? How often do
you anticipate needing to replace el-cheapo whisky-
barrel/automotive contactors? The legacy contactors
of choice have a rich field history . . . yes . . .
they DO wear out or get damaged . . . but they're
easy to replace at little cost of ownership. Further,
if you've crafted a failure tolerant system, failure
of the $low$ contactor poses no increase in risk.
Further, besides the extra acquisition costs,
what's the weight, real-estate and volume
penalties for going all solid state?
Sometimes, the most practical way to drive a nail
is with a hammer.
Bob . . .
Message 6
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| Subject: | Re: Master contactor temp? |
Good to know Bob. Thank you for sharing your knowledge. I am really happy wi
th the choice to go with contactor
Justin.
> On Jun 26, 2016, at 11:21, Robert L. Nuckolls, III <nuckolls.bob@aeroelect
ric.com> wrote:
>
> At 11:04 AM 6/25/2016, you wrote:
>> I am not sure if it would work for a starter relay or not. One behavior I
noticed is when I leave my LED instrument lights on and shut the battery of
f (this solid state relay) the LEDs will dim down while shutting off (like d
imming them with a pwm). If I shut the LEDs off with their switch, they turn
off instantly. Odd, but it doesn't seem to have any ill effects.
>
> The solid state 'contactor' is a array
> of field effect transistors controlled
> by a variable voltage applied to their
> 'gates'. When used as a 'switch', on wants
> them to be either 'on hard' or 'off hard'
> like the behavior of contacts in relays
> and switches . . . but depending on the
> circuitry that drives the gates, the
> transition time between ON and OFF states
> may not be quite as fast as for metallic
> contacts.
>
> With solid state contactors, there is a much
> longer intervale to achieve the same current
> flow as an open sent of contacts and it's
> most observable when controlling devices that
> with activity at every low currents . . . like
> an LED. In a dark room, an LED can produce
> visible light with tens of micro-amps of current
> flow.
>
> Hence, what you've observed is an ordinary
> circumstance that does not speak ill of the
> contactor's performance. Airplanes with higher
> levels of constant-on loads will drag the
> bus down faster during contactor shut-down
> make the behavior more like metallic contactors
> but there's seldom a reason to make this a
> design goal.
>
>
> Bob . . .
Message 7
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| Subject: | Re: Master contactor temp? |
There could also be something else on the bus that has a smoothing capacitor
at its front end which is providing enough charge back to the bus to hold t
he LEDs up briefly when the master is shut off.
On Jun 26, 2016, at 12:52, Justin Jones <jmjones2000@mindspring.com> wrote:
Good to know Bob. Thank you for sharing your knowledge. I am really happy wi
th the choice to go with contactor
Justin.
> On Jun 26, 2016, at 11:21, Robert L. Nuckolls, III <nuckolls.bob@aeroelect
ric.com> wrote:
>
> At 11:04 AM 6/25/2016, you wrote:
>> I am not sure if it would work for a starter relay or not. One behavior I
noticed is when I leave my LED instrument lights on and shut the battery of
f (this solid state relay) the LEDs will dim down while shutting off (like d
imming them with a pwm). If I shut the LEDs off with their switch, they turn
off instantly. Odd, but it doesn't seem to have any ill effects.
>
> The solid state 'contactor' is a array
> of field effect transistors controlled
> by a variable voltage applied to their
> 'gates'. When used as a 'switch', on wants
> them to be either 'on hard' or 'off hard'
> like the behavior of contacts in relays
> and switches . . . but depending on the
> circuitry that drives the gates, the
> transition time between ON and OFF states
> may not be quite as fast as for metallic
> contacts.
>
> With solid state contactors, there is a much
> longer intervale to achieve the same current
> flow as an open sent of contacts and it's
> most observable when controlling devices that
> with activity at every low currents . . . like
> an LED. In a dark room, an LED can produce
> visible light with tens of micro-amps of current
> flow.
>
> Hence, what you've observed is an ordinary
> circumstance that does not speak ill of the
> contactor's performance. Airplanes with higher
> levels of constant-on loads will drag the
> bus down faster during contactor shut-down
> make the behavior more like metallic contactors
> but there's seldom a reason to make this a
> design goal.
>
>
> Bob . . .
Message 8
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| Subject: | Re: Master contactor temp? |
Some object to my use of the term "ambient" as representative of the device temperature.
You would be right for solid devices, but the type 70 is a part in a
hollow housing.
To make this more clear. If the "surrounding temperature" (perhaps under the cowl)
is 130 deg F. What is the temperature of the can when the power is off? 130
deg F.
If the can is 120 deg F and the surrounding temperature is 0 degrees. What is the
temperature inside the can? It depends on the rate of heat removal, but it's
more than 120 deg F for sure, and a device rated for 122 deg F would be in trouble.
I know this is a more complicated issue. See my attachment on this subject that
was slated to have been published in ECN but can't be sure it ever was.
But don't get sidetracked. The type 70 isn't a reasonable device for GA aircraft.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=457458#457458
Attachments:
http://forums.matronics.com//files/hot_potato_121.pdf
Message 9
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| Subject: | Re: do I need to change my capacitor |
At 09:26 AM 6/25/2016, you wrote:
>
>The MGL provides for the low voltage readings, but I did not catch
>it. I was flying around with the battery voltage being shown.
>With the new voltage regulator I'm showing 13.8v to 14.4v volts
>during flight. If I turn on landing lights it will drop to about 13.4v.
>Yes, I pattern the diode to the Jabiru figure, but did not install
>the over protection. I'm now planning on doing that when I return from KOSH.
>Trio Avionics only told me that the mother boards were burnt. The
>same for MGL.
>I'll see if I can find a architecture drawings. Most of mine are
>hand drawn as I could never find a computer drawing program that I
>could use effectively.
Unless you're already proficient in CAD
drawing systems, the FAST and very effective
way to document your airplane goes something
like this.
Build a page-per-system wire book in a 3-ring
binder using #2 pencil and 'pink pearl' eraser.
Neat doesn't count at this stage. Just get all
the data down on paper so you don't have to
'go back an look' to refresh your memory of things
you did perhaps years ago.
Every time you make a change, record it. But keep
EACH page simple. Bus, breaker/fuse, wire, switch,
wire, connector, gizmo, wire, ground. This litany
might describe a landing light. Obviously, some
will be more complex but in terms of the WHOLE
airplane, each page is simple.
Download this document and check out the wirebook
pages in the back . . .
http://tinyurl.com/zlco6ke
These are examples of page-per-system drawings
that illustrate the technique for illustrating
wire segments, how and where they are terminated
and how to list all of the components and materials
that go into crafting that one system.
Make the same kinds of drawings for your airplane
filling in details as you go along. The 3-ring
binder on the shop-bench is all the tooling you
need.
When the airplane is all done and depending on
how legible your first-pass work is, you may
choose to redraw the work . . . use a straight
edge and gel pen. You can even draw your final
document on top of your draft document using
the draft data as a guide. When the final document
is complete and totally dry, use the pink pearl to
remove the pencil lines and smudges.
It takes less practice to go this route than to
search out, install and learn to use any kind
of CAD program. If you're going to do this stuff
for a living, having a CAD program may be useful.
If this but one of a very few numbers of airplanes
you're going to build, paper, pencil, eraser and
pen are excellent, time proven alternatives to
RECORD your work. The NEXT person to own your
airplane will thank you for it.
Bob . . .
Message 10
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| Subject: | Re: Master contactor temp? |
Sent from Mail for Windows 10
From: Roger
Message 11
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| Subject: | Re: Master contactor temp? |
At 10:03 AM 6/26/2016, you wrote:
>
>"Ambient" refers to the contactor temperature. But keep in mind that
>"ambient" doesn't refer to the temperature someplace outside, but AT
>and ON the contactor can.
No . . . ambient means SURROUNDING conditions . . .
>Furthermore the type to is G-position sensitive
Yes . . . more G's than it takes to pull
the wings off your airplane . . . as is
every other metallic contactor.
> vibration sensitive
Non-quantified . . . how many g's at what
frequency? Levels SMALLER than those found anywhere
on a light aircraft? I've never analyzed a
Type 70 failure that I could attribute to a
vibration stress . . . LOTS of failures attributable
to dripping water . . . a few failures due
to manufacturing defect . . . and none that
posed high-risk scenario.
> not liquid proof
Show me ONE contactor used on any TC light aircraft
that is liquid proof . . .
> and has many undesireable characterists
Many implies more than one . . . I'd settle for
just two . . .
> . . . compared to other solutions.
>
>As for my choice? I go with the Flaming River Battery Switch, or any
>of the several electronic contactor offerings, unless your mission
>doesn't take you far from home.
Can you cite any instance in the literature
where a contactor failure "far from home"
figured in elevation of risk to airframe
or people in it? If so, what were the circumstances
that promoted that failure?
>Factoid: No NASCAR vehicle uses a type-70 contactor.
For what reason(s) . . . can you cite conditions
on these vehicles that are analogous to conditions
on our airplanes?
>Factoid: Very old Type-70's were made from far better stuff.
Really? I've done some teardowns several
variations of 70 series contactors. See pictures
of inspected articles here:
http://tinyurl.com/kcc26jt
. . . they may be useful in explaining how the
materials illustrated in picture A of a failure
are 'better' than those in picture B. How
did they contribute to the failure?
One failure in a 'modern' 70 series contactor
had nothing to do with selection of materials
and lots to do with failure to solder a joint
on the production line . . .
http://tinyurl.com/zs42jpj
>Please, can we do better than "hot to the touch"
I will suggest that 'hot to touch' is more
definitive to stress boundaries than several
of your assertions above. "Too hot to touch" at
least says somewhere more than ~130 degrees.
I like "sizzle-spit" as being greater than
212 degrees. "Sticking your tongue to the flag
pole" says a whole lot colder than 32 degrees.
But 'sensitive to vibration' offers no bounded
image.
Bob . . .
Message 12
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| Subject: | Re: Master contactor temp? |
Eric M. Jones wrote:
> Please, can we do better than "hot to the touch"
We can, and I did.
If you will read my post you will see that I checked it with a thermometer and
was seeing ~120F. Or do you require an exact temperature? Or do you need some
digits to the right of the decimal point?
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=457462#457462
Message 13
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| Subject: | Re: Master contactor temp? |
>
>If the can is 120 deg F and the surrounding temperature is 0
>degrees. What is the temperature inside the can? It depends on the
>rate of heat removal, but it's more than 120 deg F for sure, and a
>device rated for 122 deg F would be in trouble.
Exactly . . .
If you take any 70 series device apart you
will find a collection of materials.
Threaded, copper terminal studs upon which
stationary contacts are formed.
A washer-like movable contact mounted to the
end of an iron armature that moves freely
within the cylindrical 'bore' of a coil
core.
The core has evolved a lot over the years.
But suffice it to say, that whether the
solenoid wires are (1) simply wound on a tube
and captured between disks of phenolic, (2)
embedded in a solidly potted assembly or (3)
wound on a complex molding that forms the
tube, end confines, terminals and mates with
contours of the shell . . . ALL materials used
must first hold components in their intended
positions while withstand expected internal
operating temperatures.
I used to work in a facility that specialized in
the design and manufacture of numerous electronic
and motor driven components . . . including the
actual motors.
I can tell you that ALL materials used in the
manufacture of a brushed DC motor including insulated
magnet wire, insulating varnishes, paper and molded
plastic insulators and components were RATED to
perform as advertised while enduring "Class H"
thermal conditions.
http://www.marathonelectric.com/generators/docs/manuals/thermal-life.pdf
Of course, these are INTERNAL conditions which
are expected to be hotter than external conditions.
122F is 50C . . . a rather benign condition for
many qualification levels in aircraft. 70C ambients
for black boxes are not uncommon. At the same time,
I can tell you that 100C ambients for most electronic
assemblies not dissipating a lot of power is no big
deal. An engineer I've worked with for years will often
throw his brass-board assemblies into the lab oven at
100C just to make sure he didn't overlook an unusually
vulnerable part in the design.
I trust this little dissertation goes to an understanding
that 'proper' temperatures for operation with limits
of design goals can be all over the map. Certainly
your cylinder heads will 'sizzle spit' under perfectly
normal conditions.
The contactor illustrated in
http://www.marathonelectric.com/generators/docs/manuals/thermal-life.pdf
demonstrates a temperature rise of ~50C with no air
flow over the device. Were we to operate this contactor
in its RATED 122F environment (70C) then we might expect the
contactor surface to go up to 120C . . . which will
sizzle-spit.
I can tell you that we didn't build a single motor
that could not be operated with surface temperatures in
sizzle-spit range . . . VERY much too hot to touch.
Hence I can assert confidently that while the observed
surface temperature for an operating 70 series contactor
is unfriendly the touch, the device is NOT being
unduly stressed internally. The 122F limit to operating
environment suggests something less than class-H ratings
for stuff inside . . . at the same time, it
poses no practical operating limits on how we use
the contactor.
Bob . . .
Message 14
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| Subject: | Re: Master contactor temp? |
Is there any evidence it's actually a limiting temperature?
>>and the only reference I can find for temperature is "Temperature Range
=93=93 -40=C2=B0F to 122=C2=B0F"
The normal operating temperature for a device is given as the temperature ra
nge within which the given electrical specification is met. There's no expec
tation the the device can't or won't work, or shouldn't be used outside that
temperature range, merely that you are somewhat on your own with respect to
its characteristics.
> On Jun 26, 2016, at 21:37, Robert L. Nuckolls, III <nuckolls.bob@aeroelect
ric.com> wrote:
>
>
> If the can is 120 deg F and the surrounding temperature is 0 degrees. What
is the temperature inside the can? It depends on the rate of heat removal, b
ut it's more than 120 deg F for sure, and a device rated for 122 deg F would
be in trouble.
Exactly . . .
If you take any 70 series device apart you
will find a collection of materials.
Threaded, copper terminal studs upon which
stationary contacts are formed.
A washer-like movable contact mounted to the
end of an iron armature that moves freely
within the cylindrical 'bore' of a coil
core.
The core has evolved a lot over the years.
But suffice it to say, that whether the
solenoid wires are (1) simply wound on a tube
and captured between disks of phenolic, (2)
embedded in a solidly potted assembly or (3)
wound on a complex molding that forms the
tube, end confines, terminals and mates with
contours of the shell . . . ALL materials used
must first hold components in their intended
positions while withstand expected internal
operating temperatures.
I used to work in a facility that specialized in
the design and manufacture of numerous electronic
and motor driven components . . . including the
actual motors.
I can tell you that ALL materials used in the
manufacture of a brushed DC motor including insulated
magnet wire, insulating varnishes, paper and molded
plastic insulators and components were RATED to
perform as advertised while enduring "Class H"
thermal conditions.
http://www.marathonelectric.com/generators/docs/manuals/thermal-life.pdf
Of course, these are INTERNAL conditions which
are expected to be hotter than external conditions.
122F is 50C . . . a rather benign condition for
many qualification levels in aircraft. 70C ambients
for black boxes are not uncommon. At the same time,
I can tell you that 100C ambients for most electronic
assemblies not dissipating a lot of power is no big
deal. An engineer I've worked with for years will often
throw his brass-board assemblies into the lab oven at
100C just to make sure he didn't overlook an unusually
vulnerable part in the design.
I trust this little dissertation goes to an understanding
that 'proper' temperatures for operation with limits
of design goals can be all over the map. Certainly
your cylinder heads will 'sizzle spit' under perfectly
normal conditions.
The contactor illustrated in
http://www.marathonelectric.com/generators/docs/manuals/thermal-life.pdf
demonstrates a temperature rise of ~50C with no air
flow over the device. Were we to operate this contactor
in its RATED 122F environment (70C) then we might expect the
contactor surface to go up to 120C . . . which will
sizzle-spit.
I can tell you that we didn't build a single motor
that could not be operated with surface temperatures in
sizzle-spit range . . . VERY much too hot to touch.
Hence I can assert confidently that while the observed
surface temperature for an operating 70 series contactor
is unfriendly the touch, the device is NOT being
unduly stressed internally. The 122F limit to operating
environment suggests something less than class-H ratings
for stuff inside . . . at the same time, it
poses no practical operating limits on how we use
the contactor.
Bob . . .
Message 15
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| Subject: | Re: Master contactor temp? |
At 09:42 PM 6/26/2016, you wrote:
>Is there any evidence it's actually a limiting temperature?
>
> >>and the only reference I can find for
> temperature is "Temperature Range '' -40=C2=B0F to 1o 122=C2=B0F"
>
>The normal operating temperature for a device is
>given as the temperature range within which the
>given electrical specification is met. There's
>no expectation the the device can't or won't
>work, or shouldn't be used outside that
>temperature range, merely that you are somewhat
>on your own with respect to its characteristics.
Temperature ratings are a bit 'squishy' . . .
like contact ratings for current and voltage.
Most ratings are bounded by calculated or
laboratory demonstrations of service life.
The 70 series contactor isn't going to burst
into flames if operated in a 150F environment.
At the same time, it would probably not demonstrate
rated life limits either. Then again, we don't
even begin to stress the service life of any
switch or contactor in a GA single engine
airplane!
The 122F/50C recommended limit probably
assumes still air . . . sitting out on a
bench. Add a little moving air and internal
temperatures will fall like a stone . . .
which translates to a boost in recommended
limit to ambient air temperature.
I may have the data in my archives somewhere
that describes temperature conditions under
the cowl on a single engine airplane. We
were setting up a cooling test on a new alternator
installation and had 8 thermocouple channels
open on the DAS.
We scattered some extra thermocouples around and
discovered that in-flight temperatures are really
rather benign . . . the hottest spikes occurred
during cool-down after engine shutdown when
air flow dropped and heat stored on the engine
mass warmed things up under the cowl.
Of course, the thermocouples only gave us
total temperature of the air at various
locations. To assess cooling effects of air
movement, we would have to repeat the experiment
by mounting the thermocouples onto power resistors
and then plotting differences between static
air and in-flight conditions with stirred air
over components that were dissipating heat.
The constellation of variables can be all over
the map when it comes to in-situ thermal management
of components in the airplane . . . hence, making
a decision to buy brand X contactor rated at 50F
versus brand Y rated at 70C could very well be
a poor cost of ownership decision.
As our ol' buddy Lord Kelvin used to say, "Until you've
measured the thing . . . your knowledge of the
science is of a meager and unsatisfactory kind."
Bob . . .
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