Today's Message Index:
----------------------
1. 03:12 PM - Re: 12 Volt DC Bench Power Supply (Bill Dube)
2. 03:12 PM - Re: Re: AeroElectric-List Digest: 29 Msgs - 02/04/06 (Bill Dube)
3. 03:19 PM - Re: 12 Volt DC Bench Power Supply (Bill Dube)
4. 06:46 PM - Flyable_Brassboards (Robert L. Nuckolls, III)
5. 07:19 PM - Alternator Stator Terminal (Roger & Alice Hoffman)
6. 07:19 PM - Alternator Stator Terminal (Roger & Alice Hoffman)
7. 08:24 PM - Bus Load Analysis (Jerry Grimmonpre)
8. 08:24 PM - Re: Alternator Stator Terminal (Robert L. Nuckolls, III)
9. 08:37 PM - Re: Flyable_Brassboards (Richard E. Tasker)
10. 10:06 PM - Re: Bus Load Analysis (Brian Lloyd)
11. 10:32 PM - Wire sizing. (DEAN PSIROPOULOS)
12. 11:15 PM - Re: 24v lamps in 14v system (Speedy11@aol.com)
Message 1
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Subject: | Re: 12 Volt DC Bench Power Supply |
--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa.gov>
I use a Toshiba laptop power supply. I put clup leads on it. It delivers
15 volts @ 2 amps (good for charging batteries). I put a power doide in
series with it to get 14.3 volts. (Just like the alternator with a full
battery.)
Brian Lloyd wrote:
>--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
>
>
>Wngsfrmhvn@aol.com wrote:
>
>
>>--> AeroElectric-List message posted by: Wngsfrmhvn@aol.com
>>
>>My first post to any list, so hope it works.
>>
>>I picked up a computer power supply a while back on a whim. 550 watt Antec,
>>says it will deliver 24A at 12V, 40A at 5V, and 32A at 3.3V. Don't know if
>>it goes to 13.8 or whether it's even suitable for benchtop use. It was $100
>>on eBay some time ago, prob not the best deal goin but...
>>
>>
>
>You can use computer supplies but many of them have minimum loads for
>all three voltages for them to work properly. That means you have to
>draw some current from the 5V and 3.3V outputs in order for the 12V
>output to work properly.
>
>And, no, there usually isn't an adjustment that will let you crank up
>the voltage to 13.8V.
>
>I have an old Astron 35A linear supply with variable voltage and current
>limit. It works wonderfully for this kind of work. You set the current
>limit just above what you expect to need and any accidental
>short-circuit is protected by the supply's current limit.
>
>
>
Message 2
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Subject: | Re: AeroElectric-List Digest: 29 Msgs - 02/04/06 |
--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa.gov>
The DC-DC converter will be pricey (and heavy.) Why not just run 12 volt
position lights?
<Warning - Blatent self promotion>
If you have an experimental, may I suggest one of the LED position light
kits I sell.
Bill Dube' http://www.killacycle.com/Lights.htm
speedy11@aol.com wrote:
>--> AeroElectric-List message posted by: speedy11@aol.com
>
> Listers,
>I have a question for you.
>I have a 12V electrical system with two batteries and one alternator. I would
like to power 24V position lights. What must I do to accomplish that?
>Is there a 12V to 24V step up device that can be installed to power only those
lights? I don't want to change the entire system to 24V.
>Stan Sutterfield
>www.rv-8a.net
>
>
>
>
>
>
>
>
>
Message 3
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Subject: | Re: 12 Volt DC Bench Power Supply |
--> AeroElectric-List message posted by: Bill Dube <william.p.dube@noaa.gov>
Didn't realise you needed big amps.
Iota is probably the most amps for the buck. You can switch it between
14.2 for charging and 13.8 for "float".
Here is a listing: http://www.oksolar.com/battery_chargers/
Robert L. Nuckolls, III wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>
>At 09:50 PM 2/3/2006 -0500, you wrote:
>
>
>
>>--> AeroElectric-List message posted by: "J. Mcculley"
>><mcculleyja@starpower.net>
>>
>>Can someone recommend a source/model of bench power supply using 110V AC
>>input with 12V DC output, capable of up to 15 amps DC? Thanks,
>>
>>Jim McCulley
>>
>>
>
> Do you really want 12v . . . or are you interested in
> simulating an operating vehicle? 13.8v is a nominal bench
> supply setting for emulating bus voltage. Here's a supply
> I used to sell until they got so cheap that the margins
> didn't fit my business model any more . . .
>
>
> http://www.radiodan.com/misc/samlex1223.htm
>
> http://www.universal-radio.com/catalog/hamps/3747.html
>
> http://www.aaradio.com/cartfile/misc%20html/samlex.html
>
>
> Bob . . .
>
>
>
>
>
>
>
>
>
Message 4
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Subject: | Flyable_Brassboards |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
Many times over the years, I've had to fabricate little circuits
for some task wherein I needed the flexibility of a brass-board
but with a reasonable degree of hardness suited for flight.
I had occasion to dig out an old tool today for another task
and thought I'd share it with the List. See:
http://www.aeroelectric.com/Pictures/Tools/flyable_brassboard_1.jpg
http://www.aeroelectric.com/Pictures/Tools/flyable_brassboard_2.jpg
I cut down a strip of experimental brass-board stock and with
a tad bit of sculpting on the belt sander, I was able to fit it to
the inside of the lid on this die-cast box. Add a d-sub or other
handy connector and you've got an enclosure with features that
permit quick fabrication but with reasonable robustness for handling
when closed up. If I expect unusual vibration, I'll use hot-glue
to stick the components and wires down to the board. The hot glue
doesn't run into the holes and strips off after the experiment is
done.
The circuit in the pictures is a gain of 100 amplifier I needed
to amplify a strain gage signal up to the range of my poor-man's
data acquisition system. The all-metal enclosure lends itself to
the shielding of relatively sensitive circuits. I keep several such
prepared boxes laying around and they've saved a lot of time when
I needed to get something up and running . . . today.
In this case, I'm setting up the data acquisition system to get
some numbers on the performance of a Schumacher Wonder Charger . . .
lots of push-buttons and indicators. Really cool battery charger.
The goal is to deduce return on investment and real utility of
this tool in the ownership and operation of and airplane (or any
other vehicle fitted with a battery). I need a gain of 60 amplifier
for the battery ammeter shunt.
If any of you are inclined to craft specialty circuits that
are best flight tested before committing to etched circuit
board . . . or you just need a one-time circuit for a test,
I can recommend the technique illustrated here.
Bob . . .
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
Message 5
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Subject: | Alternator Stator Terminal |
--> AeroElectric-List message posted by: "Roger & Alice Hoffman" <rognal@clipper.net>
I'm wiring my experimental per Z-11. I have installed a Continental IO-240-B which
came (new) with their (TCM) 60A Alternator installed. This alternator has
a threaded terminal identified as 'Stator', as well as the terminals marked Battery,
Field, and Ground.
Can anyone tell me if this alternators 'stator' terminal needs a connection of
some kind? Or leave it unconnected?
A search of the archives revealed nothing to me, nor did the Continental Engine
Operator's & Maintenance Manuals.
Thanks in advance for any advice.
R. Hoffman
Message 6
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Subject: | Alternator Stator Terminal |
--> AeroElectric-List message posted by: "Roger & Alice Hoffman" <rognal@clipper.net>
I'm wiring my experimental per Z-11. I have installed a Continental IO-240-B which
came (new) with their (TCM) 60A Alternator installed. This alternator has
a threaded terminal identified as 'Stator', as well as the terminals marked Battery,
Field, and Ground.
Can anyone tell me if this alternators 'stator' terminal needs a connection of
some kind? Or leave it unconnected?
A search of the archives revealed nothing to me, nor did the Continental Engine
Operator's & Maintenance Manuals.
Thanks in advance for any advice.
R. Hoffman
Message 7
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Subject: | Bus Load Analysis |
--> AeroElectric-List message posted by: "Jerry Grimmonpre" <jerry@mc.net>
Hi all ...
I humbly ask for input on the following and maybe create new thought ...
Load analysis: Pitot heat load vs. load of AOA (angle of attack) Sport
instrument.
Rob are you here?
When considering the imbalance of the load effects of these two items ... it
seems we squander a lot of amps on pitot heat when the AOA could substitute
while using about .4 amps and include audible warnings, as well, while
landing at any weight.
In my reading of the Lancair list, I've found there has been zero incidents
of moisture problems in the AOA ports in the outer wing D sections. This
included heavy rain with the airplane tied outside. If this port is not
affected by moisture, it seems to follow that icing may be less of a problem
with this delta P port. This applies to the AOA system called AOA Sport,
where the pressure differential is measured at the outboard wing D section.
When considering pitot heat, as a 7.5A continuous load, it would increase
most Continuous Bus loads by near 30-40%. Powering-up an AOA system pales
in comparison at only .4 amps.
Those of you with the AOA Sport ... have you found any moisture or frozen
ports?
How many have found pitot heat cleared up their airspeed indications within
moments of turning on the pitot heat?
What I'm trying to get at here is: do you think pitot heat should be listed
as continuous amps used, considering the availability of AOA and it's low
demand on amps?
Regards ...
Jerry Grimmonpre'
Message 8
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Subject: | Re: Alternator Stator Terminal |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
At 07:18 PM 2/6/2006 -0800, you wrote:
>--> AeroElectric-List message posted by: "Roger & Alice Hoffman"
><rognal@clipper.net>
>
>I'm wiring my experimental per Z-11. I have installed a Continental
>IO-240-B which came (new) with their (TCM) 60A Alternator installed. This
>alternator has a threaded terminal identified as 'Stator', as well as the
>terminals marked Battery, Field, and Ground.
>
>Can anyone tell me if this alternators 'stator' terminal needs a
>connection of some kind? Or leave it unconnected?
>
>A search of the archives revealed nothing to me, nor did the Continental
>Engine Operator's & Maintenance Manuals.
>
>Thanks in advance for any advice.
>
>R. Hoffman
The "Stator" terminal is the center tap on a "Y" connected
stator winding. This terminal has been used in a variety
of ways to sense whether or not the engine was turning
the alternator, as a signal to drive various alternator
failure detectors, ect.
I've not seen a useful application of this signal in years.
It exists only on alternators with "Y" connected windings.
In any case, you can ignore this terminal.
Bob . . .
< What is so wonderful about scientific truth...is that >
< the authority which determines whether there can be >
< debate or not does not reside in some fraternity of >
< scientists; nor is it divine. The authority rests >
< with experiment. >
< --Lawrence M. Krauss >
Message 9
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Subject: | Re: Flyable_Brassboards |
--> AeroElectric-List message posted by: "Richard E. Tasker" <retasker@optonline.net>
I understand what you are doing and know that you understand the
limitations of this type of breadboard and will not use it for long or
in any flight critical application.
However, I am not sure that everyone reading this list does.
This type of breadboard is good for bench testing of relatively low
frequency (<1MHz or so) circuits. It has a relatively large capacitance
between pins/insertion points which limits the high frequency utility
and can provide unwanted feedback in sensitive circuits. It is also not
very secure unless it is new and from a good quality manufacturer. The
insertion points tend to get loose with time, especially if one inserts
a larger lead one time and a smaller lead the next.
I would recommend that one use these boards as they were intended - try
out the circuit on the bench in a nice benign environment. When you are
satisfied that it will do what you want, then purchase one of the PCBs
available that exactly mimic the insertion points and buses and solder
your circuit on that (for instance, Radio Shack Catalog #: 276-170 -
http://www.radioshack.com/search/index.jsp?kwCatId=&kw=breadboard -
fifth one down on the page). They are also available from Digikey.
This will give a circuit that is stable and robust and could be used as
a permanent installation if so desired.
The rest of your suggestion (using the aluminum box) is a great idea!
Dick Tasker
Robert L. Nuckolls, III wrote:
>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
>
>Many times over the years, I've had to fabricate little circuits
>for some task wherein I needed the flexibility of a brass-board
>but with a reasonable degree of hardness suited for flight.
>
>I had occasion to dig out an old tool today for another task
>and thought I'd share it with the List. See:
>
>http://www.aeroelectric.com/Pictures/Tools/flyable_brassboard_1.jpg
>
>http://www.aeroelectric.com/Pictures/Tools/flyable_brassboard_2.jpg
>
>I cut down a strip of experimental brass-board stock and with
>a tad bit of sculpting on the belt sander, I was able to fit it to
>the inside of the lid on this die-cast box. Add a d-sub or other
>handy connector and you've got an enclosure with features that
>permit quick fabrication but with reasonable robustness for handling
>when closed up. If I expect unusual vibration, I'll use hot-glue
>to stick the components and wires down to the board. The hot glue
>doesn't run into the holes and strips off after the experiment is
>done.
>
>The circuit in the pictures is a gain of 100 amplifier I needed
>to amplify a strain gage signal up to the range of my poor-man's
>data acquisition system. The all-metal enclosure lends itself to
>the shielding of relatively sensitive circuits. I keep several such
>prepared boxes laying around and they've saved a lot of time when
>I needed to get something up and running . . . today.
>
>In this case, I'm setting up the data acquisition system to get
>some numbers on the performance of a Schumacher Wonder Charger . . .
>lots of push-buttons and indicators. Really cool battery charger.
>The goal is to deduce return on investment and real utility of
>this tool in the ownership and operation of and airplane (or any
>other vehicle fitted with a battery). I need a gain of 60 amplifier
>for the battery ammeter shunt.
>
>If any of you are inclined to craft specialty circuits that
>are best flight tested before committing to etched circuit
>board . . . or you just need a one-time circuit for a test,
>I can recommend the technique illustrated here.
>
> Bob . . .
>
--
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that a significant number of electrons may have been temporarily inconvenienced.
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Message 10
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Subject: | Re: Bus Load Analysis |
--> AeroElectric-List message posted by: Brian Lloyd <brian-yak@lloyd.com>
Jerry Grimmonpre wrote:
> I humbly ask for input on the following and maybe create new thought ...
> Load analysis: Pitot heat load vs. load of AOA (angle of attack) Sport
> instrument.
> Rob are you here?
I like AoA. It is one of the most useful instruments in an airplane. I
also know that neither AoA nor ASI are going to be much use when the
wing is iced up. Ice changes the airfoil shape and possibly the
effective angle of incidence. The wing will stall at a different
airspeed and probably a different angle of attack as separation of
airflow is likely to occur sooner.
So it doesn't much matter.
Well, there is one thing: if your ASI is working and you experience
stall buffet at some airspeed, at least the ASI will give you some idea
when you are in the ballpark again. In that it might be of some use if
the wing is iced up. And your AoA pressure ports will probably be
covered with the ice anyway.
But I still like that AoA instrument. I had one on my previous CJ6A and
verified its calibration from 1/4G all the way up to 5Gs. It made flying
acro a lot more comfortable because I could always just take the wing to
zero alpha and wait until I had more airspeed to recover. I never had to
deal with the airplane departing if I didn't want to.
--
Brian Lloyd 361 Catterline Way
brian-yak at lloyd dot com Folsom, CA 95630
+1.916.367.2131 (voice) +1.270.912.0788 (fax)
I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery
Message 11
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--> AeroElectric-List message posted by: "DEAN PSIROPOULOS" <dean.psiropoulos@verizon.net>
Lectric Bob:
I've been doing the wiring diagrams for my all electric RV-6 and using some
of your autocad stuff on the AEC CD as examples and starting points. Since
I'm just hacking at Autocad these help get me going faster than if I had to
start from scratch, thanks for sharing your hard work with us. Couple
questions on wire sizing. I originally bought the Whelen strobe kit (A600)
that has both the side and aft position lights with strobe in each wingtip
mounted assembly (no tail position required). I later decided to buy the
combination tail position light/strobe combo as an addition in order to help
people see me better from the rear.
I now have 5 position lights at 2.2 amps each for a total of 11 amps of load
on the circuit. I would like to run them all from one switch and have ONE
wire running from the switch down through the center console of the airplane
through the spar to a distribution block under the floor. I've been
scratching my head a little and reading and re-reading the section in your
book about "Wire Selection and Installation". Using the chart for temp rise
vs wire ga vs current capacity, it looks like a 16 GA wire would have appx a
30 deg C temp rise with 11 amps flowing through it. If I convert that to an
appx Farenheit equivalent it becomes something like an 86 deg temp rise. If
ambient is a Florida summer with the OAT at 90 deg (F) and I add these two
temps together I get 176 degrees (F) temp in free air with 11 amps in the 16
GA wire, correct?
Running this wire down through the tight confines of my center console means
that it will be near several other wires and without lots of cooling air so
I would assume that one would see the full 176 degrees around that wire in
that confined space. This is not beyond the capabilities of the Tefzel
wire I'm using but still very hot to the touch and warmer than I feel
comfortable with. So if I drop down to a 14 GA wire it looks like the temp
rise would be appx 13 deg C or 55 F which gives about a 145 deg wire temp in
free air. The is still going to be pretty warm to the touch and I'm
thinking maybe it should be derated a bit more but don't really want to run
a 12 GA wire and am not 100% sure it's needed (although on a night flight
that wire will see the full 11 amps for the entire period of time).
Are my assumptions here correct and am I really going to experience 176 deg
wire temp with 11 amps in a 16 GA wire on a 90 deg day? If so do you think
dropping to 14 GA would be sufficient or should I make it larger? Since I
don't really want to run a 12 GA wire through the tight space would two 16
or 14 GA wires work equally as well or would the current shared by each be
unequal with the resultant heating of each wire also unequal (assuming they
are tied together at both ends)? Is there a good "rule of thumb" for wire
sizing with respect to temp rise (ie. Equipment that runs continuously
should not have wire temps higher that would be uncomfortable to touch or
some such thing). Since this wire is only about 6 feet long the voltage drop
through it shouldn't be a significant factor that I see (4/1000 ohms per
foot*6 feet*14 volts = .33 volts) so that leaves temperature.
Also, I see on your diagrams for landing and recognition lights you show a
resistor of unknown value between the ground connection and the light. I
assume this is simply there to remind us that there is some loss in lines
that long and also some loss in the return line (aircraft structure). Is
this assumption correct or is there a reason for the resistors there? Any
other word of wisdom would be most welcome. Thanks.
Dean Psiropoulos
RV-6A N197DM
Knee deep in Autocad and wire
Message 12
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Subject: | Re: 24v lamps in 14v system |
--> AeroElectric-List message posted by: Speedy11@aol.com
In a message dated 02/06/06 3:08:26 AM Eastern Standard Time,
aeroelectric-list-digest@matronics.com writes:
> Listers,
>I have a question for you.
>I have a 12V electrical system with two batteries and one alternator. I
>would like to power 24V position lights. What must I do to accomplish that?
>Is there a 12V to 24V step up device that can be installed to power only
>those lights? I don't want to change the entire system to 24V.
>Stan Sutterfield
Have you considered changing the light bulbs in
the position light fixtures? They're generally
available in both 12 and 24 volt versions.
Bob . . .
The LED position lights are not available in 12V - only 24V.
Is there a way to convert 12V to 24V so as to power the lights?
Stan Sutterfield
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