Today's Message Index:
----------------------
1. 08:00 AM - Re: Question about panel light dimmers (Eric M. Jones)
2. 05:48 PM - Re: Re: Low voltage indicator for LR3 (Robert L. Nuckolls, III)
3. 11:10 PM - New toy in the AEC shop . . . (Robert L. Nuckolls, III)
4. 11:50 PM - Re: New toy in the AEC shop . . . (n801bh@netzero.com)
Message 1
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| Subject: | Re: Question about panel light dimmers |
A very good explanation of how voltage regulators, both switching and linear, work
is contained in:
http://www.national.com/appinfo/power/files/f4.pdf
But it should be said that 1.5A does not mean there is any margin above than at
all--NONE. Otherwise it would be called a 1.6 Amp (or whatever)regulator. There
are protection circuits onboard, but they DO DEPEND on some operating conditions
being met. This is not always clear to the designer.
I sell tons of 1.5A LM317-based voltage regulators (EGPAVR) on my website. I have
also made these in slightly larger 2A and 3A versions.
Above a few amps the game goes to switching regulators. BUT!!, in my humble opinion,
there is a large zone where a larger, heavier, linear regulator is still
preferable, since it is more reliable AND is electrically quiet. I have abandoned
the use of switching regulators in some of my applications for this reason.
Yes, squelching the RFI/EMI is possible, but why bother?
I have seen some LED dimmers that are just horrendous. They use switching regulators
with variable frequencies. They are guaranteed to induce wild hallucinatory
visions in high-vibration environments.... Like chewing on hard candy while
looking at a computer monitor.
--------
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=166909#166909
Message 2
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| Subject: | Re: Low voltage indicator for LR3 |
>
>I am wiring per Z-13/8.
>
>If I have a main alternator failure, the LR-3 indicator will tell me.
>I switch on the Endurance bus and switch off the main bus, the
>indicator will go out, since there is no power there at all.
Yes, but this is a plan-B activity that is only expected to
be implemented in case of a rare event . . . failure of the
main alternator.
>At this point, I need to switch on the aux alternator. As drawn,
>there is no low voltage indicator to show if this alternator is
>working. In an emergency, I might forget to do this.
Failure of the main alternator is not an emergency. It's
an emergency only if you have no alternatives i.e, you
have no back up engine driven power source and you haven't
the foggiest notion of how long your battery will run goodies
in the endurance mode.
> I usually good
>with checklists, but an indicator would be helpful.
How about a voltmeter. Does one of your relatively low
power digital panel-wiggets have a voltmeter function?
>This also means there are 3 switches I could accidentally leave on
>after a flight or maintenance that would ensure a depleted battery
>before the next flight.
Are there no electro-whizzies on the panel that stay
lit up when the endurance bus is hot? . . . and three
switches? What's going to stay on un-annunciated besides
the e-bus alternate feed switch? Oh, yeah, the aux alternator
switch being left on would leave a hundred+ millamps of draw
on the battery.
>I could have 3 indicators for the switches and 2 low voltage
>indicators. However, I really only need 1 indicator that indicates
>low voltage in flight while running on either alternator, acting as an
>idiot light after shutdown.
>By adding another pole to the endurance bus and aux alternator
>switches (main bus already has a usable switched to ground pole on its
>switch), I can easily sense the switch positions. However, to avoid
>an indicator continuously lit in flight, these contacts need to
>activate a low voltage detector with a threshold abow the normal
>battery voltage, but below the charging voltage.
>
>So depending on the value of the internal resistor driving the gate of
>the FET, it could turn on my LED, which is essentially pulled to
>ground from battery voltage through a 680 ohm resistor.
I think you're making this more complicated than
it needs to be. If the scenario that creates the situation
you're guarding against happens every fifth flight, there's
a significant human factors consideration for adding the
extra indication/warning features. But your adding "stuff"
to a system to remind you that you've just experienced
a main alternator failure. Therefore, in addition a need for
getting out the toolbox after you land, you need additional
reminding to shut off the aux alternator and e-bus alternate
feed switches?
I considered low voltage warning lights for the e-bus architecture
some years ago but decided against it. Flying on the e-bus only
whether supported by the SD-8 or not is an extra-ordinary happening.
An event that should cause give the pilot a heightened awareness
of protocols for a sweat-free termination of the flight.
Bob . . .
Message 3
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| Subject: | New toy in the AEC shop . . . |
Since I no longer enjoy access to the labs at H-B,
I've been gathering some useful tools up to enhance
our development in the 'Connection's shops. I picked
this temperature chamber up off Ebay a few weeks ago for
$150 and paid another $150 to have it shipped!
It's a little bigger brother to the very first
chamber I bought at Electro-Mech about 30 years
ago! Had to do a some work with door seals,
CO2 plumbing and much scrubbing with 409 and
acetone but it cleaned up pretty well. Just
got it operational and tested. Gets down
to -60C in about 20 minutes, back up to 80C
in under 15 minutes and controls to within
2 degrees C.
http://www.aeroelectric.com/Pictures/Tools/Temperature_Chamber_2.jpg
I think it will do for the moment to get some
work out for a customer this weekend. I've found
a modern digital device to replace the analog
heating/cooling controller. I'll replace the Fluke
portable thermocouple readout with a permanent digital
display and selector switch for about 5 channels of
thermocouple. I need to build a CO2 valve-open
timer so that I tell when a bottle is about to
go empty. This thing uses the liquid CO2 from bottles
with dip tubes. They're essentially constant pressure
until the liquid runs out whereupon you loose cooling
very quickly. But by monitoring total valve-open time
I can get a pretty good calibration on pounds of
CO2 consumed.
Hmmmm . . . wonder if I need to hit up Mr. Gore
for some carbon-credits. I'm going to dump about
100# of CO2 this weekend. Maybe I'd better get
him to plant some trees for me or something.
I'd forgotten how heavy those bottles are! I
think I'll run a hard line from the garage down
to the basement shop so I don't have to lug them
on the stairs! I'm getting too old for that kind
of work!
You can even warm TV dinners in it!
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
Message 4
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| Subject: | Re: New toy in the AEC shop . . . |
That rig should be very benificial in testing componants. Great buy Bob.
.. Now for some comedy... If you do heat up TV dinners in it and you get
the runs from bad beef does one need to purchase a new rectumfier or ju
st recaliberate the old one ?? :< ))..........
do not archive
Ben Haas
N801BH
www.haaspowerair.com
-- "Robert L. Nuckolls, III" <nuckolls.bob@cox.net> wrote:
olls.bob@cox.net>
Since I no longer enjoy access to the labs at H-B,
I've been gathering some useful tools up to enhance
our development in the 'Connection's shops. I picked
this temperature chamber up off Ebay a few weeks ago for
$150 and paid another $150 to have it shipped!
It's a little bigger brother to the very first
chamber I bought at Electro-Mech about 30 years
ago! Had to do a some work with door seals,
CO2 plumbing and much scrubbing with 409 and
acetone but it cleaned up pretty well. Just
got it operational and tested. Gets down
to -60C in about 20 minutes, back up to 80C
in under 15 minutes and controls to within
2 degrees C.
http://www.aeroelectric.com/Pictures/Tools/Temperature_Chamber_2.jpg
I think it will do for the moment to get some
work out for a customer this weekend. I've found
a modern digital device to replace the analog
heating/cooling controller. I'll replace the Fluke
portable thermocouple readout with a permanent digital
display and selector switch for about 5 channels of
thermocouple. I need to build a CO2 valve-open
timer so that I tell when a bottle is about to
go empty. This thing uses the liquid CO2 from bottles
with dip tubes. They're essentially constant pressure
until the liquid runs out whereupon you loose cooling
very quickly. But by monitoring total valve-open time
I can get a pretty good calibration on pounds of
CO2 consumed.
Hmmmm . . . wonder if I need to hit up Mr. Gore
for some carbon-credits. I'm going to dump about
100# of CO2 this weekend. Maybe I'd better get
him to plant some trees for me or something.
I'd forgotten how heavy those bottles are! I
think I'll run a hard line from the garage down
to the basement shop so I don't have to lug them
on the stairs! I'm getting too old for that kind
of work!
You can even warm TV dinners in it!
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
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