Today's Message Index:
----------------------
1. 05:42 AM - Re: B&C 40 amp alternator : "F" tab? (Robert L. Nuckolls, III)
2. 05:42 AM - Re: B&C 40 amp alternator : "F" tab? (Robert L. Nuckolls, III)
3. 06:18 AM - Myths and urban ledgends about motors (Eric M. Jones)
4. 07:03 AM - Re: Myths and urban ledgends about motors (Paul Messinger)
5. 07:15 AM - Using LEDs as aircraft beacons (Eric M. Jones)
6. 07:32 AM - SL 30 Intercom (Gerry Holland)
7. 07:58 AM - Re: Myths and urban ledgends about motors (Robert L. Nuckolls, III)
8. 08:37 AM - Re: Myths and urban legends about motors (Robert L. Nuckolls, III)
9. 09:33 AM - Re: Using LEDs as aircraft beacons (Dave Morris)
10. 09:46 AM - Re: Pitot Tube Wire (Brett Ferrell)
11. 11:47 AM - Re: Myths and urban legends about motors (Jerzy Krasinski)
12. 12:44 PM - microair wiring question (RVEIGHTA@aol.com)
13. 01:36 PM - OV Protection Module (Rhett Westerman)
14. 04:14 PM - Re: NiMH batteries (Harold Kovac)
15. 05:07 PM - Fw: B&C 40 amp alternator : "F" tab? (Rick Fogerson)
16. 05:36 PM - Re: Fw: B&C 40 amp alternator : "F" tab? (Robert L. Nuckolls, III)
17. 05:42 PM - Re: microair wiring question (Robert L. Nuckolls, III)
18. 05:53 PM - Re: Myths and urban legends about motors (Robert L. Nuckolls, III)
19. 07:10 PM - Re: Reusing batteries (AI Nut)
20. 07:19 PM - Re: cooling fans, ONE DOLLAR (AI Nut)
21. 08:42 PM - Re: OV Protection Module (Robert L. Nuckolls, III)
22. 08:52 PM - Re: NiMH batteries (Robert L. Nuckolls, III)
23. 08:57 PM - Re: To E-Buss or not To E-buss (Robert L. Nuckolls, III)
24. 08:59 PM - Re: Engine Controls & Grounding (Robert L. Nuckolls, III)
25. 09:02 PM - Re: Pitch Trim Motor Slowdown (Robert L. Nuckolls, III)
26. 10:27 PM - Re: Myths and urban legends about motors (Jerzy Krasinski)
Message 1
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| Subject: | Re: B&C 40 amp alternator : "F" tab? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 04:21 PM 12/6/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
>
>Hi Bob,
>Didn't get any instructions with alt. Which tab do you wire for field,
>horizontal or vertical oriented tab or does it matter?
>Thanks, Rick Fogerson
>Boise, ID
>RV3 wiring
Last time I knew, they were tying ALL tabs together
after removing the built in regulator. You should
be able to use any one.
Bob . . .
Message 2
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| Subject: | Re: B&C 40 amp alternator : "F" tab? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 08:41 PM 12/6/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Dan Checkoway" <dan@rvproject.com>
>
>Rick,
>
>The instructions that came with my B&C 40-amp alternator said simply to jump
>the terminals together at the connector with a little jumper wire.
The jumper is a sort of "redundancy" thing . . . either tab or both
can be wired to your regulator.
Bob . . .
Message 3
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| Subject: | Myths and urban ledgends about motors |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
Here is a great little motor speed control. The drive to the motor is
periodically interrupted and back-EMF sampled. Nice!
http://www.elecdesign.com/Articles/Index.cfm?ArticleID=5763
Regards,
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge MA 01550-2705
Phone (508) 764-2072
Email: emjones@charter.net
When trouble arises and things look bad, there is always one individual
who perceives a solution and is willing to take command.
Very often, that individual is crazy.
--Dave Barry
Message 4
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| Subject: | Re: Myths and urban ledgends about motors |
--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
Thanks for the reference. That is one way of properly reducing motor speed
with out drastically reducing motor power (torque).
The basic problem using series resistance to control speed is loss of torque
in the motor. Resistive speed control is simple and works well where the
motor torque is several times more powerful than needed. However if you need
the same torque at a lower speed the series resistor is NOT the way to go.
The referenced circuit provides the same torque over a wide range of speed.
Paul
----- Original Message -----
From: "Eric M. Jones" <emjones@charter.net>
Subject: AeroElectric-List: Myths and urban ledgends about motors
> --> AeroElectric-List message posted by: "Eric M. Jones"
<emjones@charter.net>
>
> Here is a great little motor speed control. The drive to the motor is
> periodically interrupted and back-EMF sampled. Nice!
>
> http://www.elecdesign.com/Articles/Index.cfm?ArticleID=5763
>
> Regards,
> Eric M. Jones
> www.PerihelionDesign.com
> 113 Brentwood Drive
> Southbridge MA 01550-2705
> Phone (508) 764-2072
> Email: emjones@charter.net
>
> When trouble arises and things look bad, there is always one individual
> who perceives a solution and is willing to take command.
> Very often, that individual is crazy.
> --Dave Barry
>
>
Message 5
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| Subject: | Using LEDs as aircraft beacons |
--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
I have posted a PDF of this subject on my website for those interested.
Comments please!
http://www.periheliondesign.com/aircraftbeaconsusingleds.pdf
do not archive
Eric
"People don't appreciate how very difficult it is to be a princess."
--Princess Diana
Message 6
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--> AeroElectric-List message posted by: Gerry Holland <gnholland@onetel.com>
Slightly delayed response but here is some information from a friend who
flies with the Apollo SL40 (same intercom)
>I'd like to hear some thoughts about the quality of the built-in intercom
In the SL30. Have any of you utilized it? Is it sufficiently adjustable to
use along with a set of Bose X headsets as the main pilot/passenger
communications setup in a Glasair?
I have the identical intercom in the SL40. I use a pair of Peltor headsets
which I have modified to ANR. The setup works very well. The intercom has
most if not all the advantages of the stand alone intercoms with the benefit
of simpler wiring. I particularly like the ability to listen on the standby
freq (in effect you have two receivers). The only thing to watch out for is
that although the Apollo series minimises the use of panel area their sets
are very deep so make sure you have enough panel depth.
I have no knowledge of the Bose headsets but I doubt if that will be a
problem.
The most common problem is if two different makes of headset are used in the
same installation. Also if you changed from one make of headsets to another
you may find you have to reset the preset settings for things like squelch
or side tone volume but these changes are easily done using the front panel
controls in a setup routine.
As with all radio installations pay particular attention to screening the
mic/tel leads and avoid earth loops. There is more quality lost through poor
installation than the difference between the quality of the individual
products.
Hope this helps.
Regards
Gerry
Gerry Holland
Europa 384 G-FIZY
Trigear with 912 and Arplast CS Prop.
Fuselage being Painted, Wings ready to paint, Flying surfaces painted
Airframe Wiring complete, Full Size Panel 50% done . Includes Dynon EFIS,
KMD 150,
Icom A-200 and SL70 Transponder. AoA Fitted.
Activity on Panel completion, Design and build Heater Unit.
+44 7808 402404
gnholland@onetel.com
Message 7
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| Subject: | Re: Myths and urban ledgends about motors |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:22 AM 12/7/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>Here is a great little motor speed control. The drive to the motor is
>periodically interrupted and back-EMF sampled. Nice!
>
>http://www.elecdesign.com/Articles/Index.cfm?ArticleID=5763
>
>Regards,
>Eric M. Jones
This is an excellent example of speed sampled feedback
servo control of motor speed. D1 is used to sample Kb
of the motor during duty-cycle OFF time of the power
controller. As I pointed out in my missive of yesterday,
Kb is the GENERATOR constant of the PM motor. When you're
not supplying energy to the motor to hold/increase speed,
the power switch is OFF and whatever voltage appears at
the power input lead to the motor is a DIRECT MEASUREMENT
of present motor speed.
Obviously, one cannot use this self-generating tachometer
feedback technique if your design ever calls for 100% duty
cycle of motor power . . . Unless you always have at least
some tiny OFF-time, the feedback circuit goes blind and
can no longer sense motor speed.
This technique can be used only with motors having fixed
field like a permanent magnet or wound-field with a constant
excitation supply. If you DO have a wound field motor and a
tight speed control requirement, then you have to REGULATE
CURRENT to the field rather tightly. Kb = Speed times Field
Flux. In a permanent magnet motor, field flux is constant
so monitoring of OFF-time Kb is a valid representation of
motor speed.
In a wound field motor, as supply voltage goes up, field
flux increases and tells the speed control servo loop that
motor speed has increased while in fact, it has not. This
causes the system to slow down if voltage increased. Further,
copper used to wind the field has a relatively strong
positive temperature coefficient. As the motor warms up,
field resistance goes up causing field current to go down
if the field is supplied from a constant voltage source.
Since field flux is amperes times turns of wire, one can
wash out temperature and supply voltage effects on field
flux by driving the field from a relatively precise
CONSTANT CURRENT supply.
Bob . . .
Message 8
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| Subject: | Re: Myths and urban legends about motors |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 07:03 AM 12/7/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: "Paul Messinger" <paulm@olypen.com>
>
>Thanks for the reference. That is one way of properly reducing motor speed
>with out drastically reducing motor power (torque).
. . . it helps to be more specific as to what increased R
does . . . I believe this has been a source from which
myths and legends are born. The MOTOR'S ability to convert
electrical energy into mechanical energy is a constant
defined by physical characteristics and quantified by
Kt, Kb and internal impedance. The SYSTEM's ability
adds more constraints of total loop resistance, supply
voltage, and character of the load on the motor.
If one puts power to a motor with a locked rotor, then
Kb = 0 and torque is now Eapplied/R. In the hypothetical
motor I defined yesterday, the 12v locked rotor current
would be 12 volts/1 ohm or 12 amps. Torque would be 12 oz-inches
or the most you could ever get out of this motor with
12 Volts applied. Even with this very large (and probably
damaging) torque value, POWER from the motor is zero.
We have lots of force but no motion, no power.
When we add series resistance, max torque (locked rotor
value) obviously goes down because max current is limited.
2 ohms series resistance raises total resistance to 3
ohms making 4A and/or 4 oz-in the max torque that can be
delivered. Under heavy loads, MOST of the system's energy
input is being tossed off as heat in the resistor.
I've designed PM motor controls to operate in a CONSTANT
CURRENT mode. In one case, I needed a vacuum pump that
would run a relatively constant pressure differential
without use of a pressure regulator. The miniature diaphragm
pump would present a rather constant load (torque) to the
motor when the desired pressure differential was achieved.
The easiest thing to do was operate the motor from
a constant current source. It would run fast initially
when volumes of air were being moved (getting a substantial
amount of power from the motor because work was being done)
but when the desired pressure was reached, the motor would
stall and quite rotating. If pressure dropped, the motor
would turn over a few revolutions and stop again when
torque required to increase pressure was higher than
torque available due to purposefully limited supply
current to the motor. In this case, the motor torque
was maxed out but motion was zero . . . I.e. no work
being done and no power being delivered.
>The basic problem using series resistance to control speed is loss of torque
>in the motor. Resistive speed control is simple and works well where the
>motor torque is several times more powerful than needed.
. . . or when torque is relatively constant like the a/c
blower motor on vehicles.
> However if you need
>the same torque at a lower speed the series resistor is NOT the way to go.
>The referenced circuit provides the same torque over a wide range of speed.
correct . . . but the driving simple-idea is that voltage to
the motor is adjusted in response to maintain constant speed
IRRESPECTIVE of the load (torque) taken from the motor. Given
further that there are no fixed limits to max torque other than
99% duty cycle and series motor resistance, one can get full
rated torque out of the motor at any speed. POWER on the other
hand is SPEED x TORQUE. Even with this constant speed controller,
POWER from the motor will be a tiny fraction of rated output
at low speed settings not because torque is limited but because
speed is limited.
I'll suggest it's useful to use the words torque, speed, power and
energy in more precise language so as improve understanding and
quash the myths before the flourish . . . or at least cut off
oxygen from those already loose in the wild.
Bob . . .
Message 9
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| Subject: | Re: Using LEDs as aircraft beacons |
--> AeroElectric-List message posted by: Dave Morris <dave@davemorris.com>
Great article! But you should warn people not to head for the LED store
until they have finished the article! LOL!
Dave Morris
At 09:19 AM 12/7/2003, you wrote:
>--> AeroElectric-List message posted by: "Eric M. Jones" <emjones@charter.net>
>
>I have posted a PDF of this subject on my website for those interested.
>Comments please!
>
>http://www.periheliondesign.com/aircraftbeaconsusingleds.pdf
>
>do not archive
>
>Eric
>
>"People don't appreciate how very difficult it is to be a princess."
> --Princess Diana
>
>
Message 10
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| Subject: | Re: Pitot Tube Wire |
--> AeroElectric-List message posted by: "Brett Ferrell" <bferrell@123mail.net>
Sorry, been staring at wiring diagrams too long. It's an AN5812, you can
such a pitot at AS&S:
http://www.aircraftspruce.com/catalog/inpages/heatedptubes.php, though I got
my from Velocity directly.
I have the 22759/16 type wire, but when I checked the /1 it, in fact, very
different wire. Is it generally believed to be acceptable to make this
substitution?
Brett
----- Original Message -----
From: <Richard@riley.net>
Subject: Re: AeroElectric-List: Pitot Tube Wire
> --> AeroElectric-List message posted by: Richard@Riley.net
>
> I can't help with your question, but do you have a source for that
> pitot? I don't find it with Google.
>
> At 06:58 PM 12/6/03 -0500, you wrote:
> >--> AeroElectric-List message posted by: "Brett Ferrell"
> ><bferrell@123mail.net>
> >
> >Bob/folks,
> >
> >My heated pitot (AN315-1 from AeroInstruments) calls for MIL spec 22759/1
> >wire to hook it up with. Where can I get a good source for a short
length
> >of this specialty wire? Also, it claims to only draw 6.4-8 amps, so 18GA
> >would be sufficient correct? I expected to need bigger wire. Thanks.
>
>
Message 11
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| Subject: | Re: Myths and urban legends about motors |
--> AeroElectric-List message posted by: Jerzy Krasinski <krasinski@direcway.com>
There is yet another way to get a motor with constant rpm, not slowing
down under load, and able to produce huge torque if necessary. It is
done by sensing the current through the motor and making a positive
feedback loop to increase voltage driving the motor by the amount equal
to the voltage drop on internal resistance of the motor. This way the
circuit compensates for the voltage drop on the internal resistance,
effectively creating external negative resistance equal to the internal
resistance of the motor. If the voltage driving the whole driving
circuit remains constant, the motor runs at a constant speed no matter
what load, as if its coils were made out of superconductor with zero
resistance. Of course a practical circuit will eventually slow down when
the driving circuit output reaches its maximum available voltage.
Such a circuit is not as universal as say a voltage regulator, and it
must be tuned to match the internal resistance of the particular motor.
Also, perfect compensation of internal resistance is difficult because
pure metals, Cu included, have large thermal coefficient of resistance,
which means that internal resistance of a motor depends on temperature,
and the circuit migh get unstable if the compensation was pushed too far.
A circuit like that is not more complicated than a constant voltage
regulator.
Jerzy
>
>
Message 12
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| Subject: | microair wiring question |
--> AeroElectric-List message posted by: RVEIGHTA@aol.com
Bob, I purchased a microair 760 from you along with a wiring harness a couple
years ago, but I didn't receive your wiring instructions ( I wired it per the
diagram in the small blue manual).
Due to some problems with audio quality I am now in the process of rewiring
my jacks and using fiberglass jack mounts, which brings me to my question; I
pulled up two of your wiring diagrams - one was "Aircraft Microphone Jack
Wiring" and the other was entitled "Microair MA-760 Transceiver Wiring Diagram
Standard Installation" and there seems to be a conflict regarding grounding.
In the first diagram, it shows the PTT ground wire at each mic jack connected
to the sleeve along with the shield of the three conducter cable.
In the second case, you show the PTT ground wires not attached to the mic
sleeves but connected together with the headphones and intercom ground and from
there on to ship's instrument ground.
Which is the correct wiring or are both correct?
Thanks,
Walt Shipley
Message 13
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| Subject: | OV Protection Module |
--> AeroElectric-List message posted by: "Rhett Westerman" <Rhettwesterman@cox.net>
Bob,
I have a Glastar and use your OV Module. The plane has been flying since 98
and has approx 800 hours on it. Last year the OV Module went out and it
appears to have gone out again. About 150 hours on the new one you sent me.
It keeps tripping and blowing the fuse. This occurred three times today. I
have the Vision system which allows me to see the high and low voltages for
the flight. Each time the high voltage was 14.2 volts. I am unsure of the
sampling rate of the vision, but if there are voltage spikes they are faster
then the vision can catch and it had three tries.
From what I have seen, this seems very unusual......any ideas....or am I
just getting bad modules?
best,
Rhett
Message 14
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| Subject: | Re: NiMH batteries |
--> AeroElectric-List message posted by: "Harold Kovac" <kayce@joimail.com>
Try Radio Shack, expensive but they're there.
----- Original Message -----
From: <j1j2h3@juno.com>
Subject: Re: AeroElectric-List: NiMH batteries
> --> AeroElectric-List message posted by: j1j2h3@juno.com
>
> Does anyone know of a source for rechargeable lithium batteries in AA, C
> or D sizes? Are the "non-rechargeable" lithium batteries truly
> non-rechargeable, or is this a CYA statement from the manufacturers?
> What happens if you try?
>
> Jim Hasper - RV-7 just starting empennage (setting up shop in Franklin,
> Tennessee)
>
> Do not archive
>
>
Message 15
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| Subject: | Fw: B&C 40 amp alternator : "F" tab? |
--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
----- Original Message -----
From: Rick Fogerson
Subject: B&C 40 amp alternator : "F" tab?
Hi Bob,
Didn't get any instructions with alt. Which tab do you wire for field, horizontal
or vertical oriented tab or does it matter?
Thanks, Rick Fogerson
Boise, ID
RV3 wiring
Message 16
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| Subject: | Re: Fw: B&C 40 amp alternator : "F" tab? |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 06:09 PM 12/7/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
>
>
>----- Original Message -----
>From: Rick Fogerson
>To: aeroelectric-list@matronics.com
>Subject: B&C 40 amp alternator : "F" tab?
>
>
>Hi Bob,
>Didn't get any instructions with alt. Which tab do you wire for field,
>horizontal or vertical oriented tab or does it matter?
>Thanks, Rick Fogerson
>Boise, ID
>RV3 wiring\]
It doesn't matter.
Bob . . .
Message 17
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| Subject: | Re: microair wiring question |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:44 PM 12/7/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: RVEIGHTA@aol.com
>
>Bob, I purchased a microair 760 from you along with a wiring harness a couple
>years ago, but I didn't receive your wiring instructions ( I wired it per the
>diagram in the small blue manual).
>
>Due to some problems with audio quality I am now in the process of rewiring
>my jacks and using fiberglass jack mounts, which brings me to my question; I
>pulled up two of your wiring diagrams - one was "Aircraft Microphone Jack
>Wiring" and the other was entitled "Microair MA-760 Transceiver Wiring
>Diagram
>Standard Installation" and there seems to be a conflict regarding grounding.
>
>In the first diagram, it shows the PTT ground wire at each mic jack connected
>to the sleeve along with the shield of the three conducter cable.
>
>In the second case, you show the PTT ground wires not attached to the mic
>sleeves but connected together with the headphones and intercom ground and
>from
>there on to ship's instrument ground.
>
>Which is the correct wiring or are both correct?
Download instructions at:
http://www.aeroelectric.com/Catalog/avionics/760imB.pdf
Lets talk from those pages about any questions you have. What are
the links from which you downloaded documents that conflict?
Bob . . .
Message 18
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| Subject: | Re: Myths and urban legends about motors |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:09 PM 12/7/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: Jerzy Krasinski
><krasinski@direcway.com>
>
>There is yet another way to get a motor with constant rpm, not slowing
>down under load, and able to produce huge torque if necessary. It is
>done by sensing the current through the motor and making a positive
>feedback loop to increase voltage driving the motor by the amount equal
>to the voltage drop on internal resistance of the motor. This way the
>circuit compensates for the voltage drop on the internal resistance,
>effectively creating external negative resistance equal to the internal
>resistance of the motor. If the voltage driving the whole driving
>circuit remains constant, the motor runs at a constant speed no matter
>what load, as if its coils were made out of superconductor with zero
>resistance. Of course a practical circuit will eventually slow down when
>the driving circuit output reaches its maximum available voltage.
>
>Such a circuit is not as universal as say a voltage regulator, and it
>must be tuned to match the internal resistance of the particular motor.
>Also, perfect compensation of internal resistance is difficult because
>pure metals, Cu included, have large thermal coefficient of resistance,
>which means that internal resistance of a motor depends on temperature,
>and the circuit migh get unstable if the compensation was pushed too far.
>
>A circuit like that is not more complicated than a constant voltage
>regulator.
I've tried that with some success. As you've noted, it has to
be "tuned" to individual system characteristics which makes
it more difficult to offer plug-n-play spares for controllers
and motors. I was having trouble too keeping the system stable
over wide temperature ranges . . . the positive feedback would
be sufficient to cause instability. This was 20+ years ago with
mostly discrete components. Are you aware of any newer choices
for hardware to implement this control philosophy?
Bob . . .
Message 19
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| Subject: | Re: Reusing batteries |
--> AeroElectric-List message posted by: "AI Nut" <ainut@earthlink.net>
Um, that made my head hurt.
8-)
AI Nut
----- Original Message -----
From: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Reusing batteries
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 11:31 PM 12/5/2003 -0500, you wrote:
> >--> AeroElectric-List message posted by: "Fergus Kyle" <VE3LVO@rac.ca>
> >
> >" The most life any one battery would see would be three years (one in
the
> >plane and two in the car)."
> >
> >I don't think so.
>
> It's helpful to explain your deduction. If the airplane has
> one battery changed out every year with used battery rotate to
> car, then next year, one would be rotating a two year battery
> out of the car in exchange for a one-year battery out of the
> airplane. If the airplane has two batteries then a one year
> battery rotates from main battery to aux battery and two year
> old aux battery goes to car. At next annual, a three year old
> battery in car gets replaced with another two year old battery
> from the airplane. I'll suggest that in later scenario, total
> battery service would be three years with two of those years
> in the airplane.
>
> Bob . . .
>
>
Message 20
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| Subject: | Re: cooling fans, ONE DOLLAR |
--> AeroElectric-List message posted by: "AI Nut" <ainut@earthlink.net>
How about the computer case fans? About $5, 12vdc, sturdy frame, and
(usually) quiet.
AI Nut
----- Original Message -----
From: "Dan Checkoway" <dan@rvproject.com>
Subject: AeroElectric-List: cooling fans, ONE DOLLAR
> --> AeroElectric-List message posted by: "Dan Checkoway"
<dan@rvproject.com>
>
> There's been some talk about cooling fans, and people have mentioned 8-12
> bucks (I think). No need to spend that much:
>
> $1 each: http://store.yahoo.com/nexfan03/evcafan80bl.html
>
> Or, for quieter, ball bearing, $4.99 each:
> http://store.yahoo.com/directron/uc001btc.html
> http://store.yahoo.com/directron/80l1a.html
>
> )_( Dan
> RV-7 N714D
> http://www.rvproject.com
>
>
Message 21
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| Subject: | Re: OV Protection Module |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:36 PM 12/7/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Rhett Westerman"
><Rhettwesterman@cox.net>
>
>Bob,
>
> I have a Glastar and use your OV Module. The plane has been flying since 98
>and has approx 800 hours on it. Last year the OV Module went out and it
>appears to have gone out again. About 150 hours on the new one you sent me.
>
> It keeps tripping and blowing the fuse. This occurred three times today. I
>have the Vision system which allows me to see the high and low voltages for
>the flight. Each time the high voltage was 14.2 volts. I am unsure of the
>sampling rate of the vision, but if there are voltage spikes they are faster
>then the vision can catch and it had three tries.
>
> From what I have seen, this seems very unusual......any ideas....or am I
>just getting bad modules?
Refresh my memory. When it "went out" the first time, did you send it
to me for modification or did I send you a new one. When you say "fuse"
do you mean circuit breaker? The Vision Micro will not "see" the kind
of transient usually common to nuisance tipping an crowbar ov module.
If the first one was "bad" and sent back to me for mod, I would have
brought it up to date with current production. What equipment was
ON while the OV module was tripping? Was this configuration much
different than previous flight activity? Would you be willing to try
an experiment to see if we can isolate any potential antagonist
systems?
Bob . . .
Message 22
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| Subject: | Re: NiMH batteries |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:51 PM 12/6/2003 -0800, you wrote:
>--> AeroElectric-List message posted by: j1j2h3@juno.com
>
>Does anyone know of a source for rechargeable lithium batteries in AA, C
>or D sizes? Are the "non-rechargeable" lithium batteries truly
>non-rechargeable, or is this a CYA statement from the manufacturers?
>What happens if you try?
See http://www.greenbatteries.com/documents/Li-ion_Battery_FAQ.htm
and in particular:
http://www.greenbatteries.com/documents/Li-ion_Battery_FAQ.htm#Li-ion%20in%20AA
Bob . . .
Message 23
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| Subject: | Re: To E-Buss or not To E-buss |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
>
>
> > Yup. The e-bus alternate feed path has two purposes. (1) Second path
> > to most reliable power source in event battery contactor is lost
>
>Good point.
>Bob, is it possible to keep the alternate feed switch, eliminate the E-bus
>connecting the feed to the main bus? If possible would you need to use the
>diode turned to feed the main bus or eliminate the diode all together?
>
> >(2) means by which battery only operations loads may be reduced
> > to minimum en route values for endurance. The fact that you've added
> > and SD-8 only means that e-bus loads can now be as great as 8-10 amps
> > so that the battery can be held in reserve for approach to landing
> > by turning the battery master back on. If the battery master has
> > failed, difference in outcome of flight is insignificant.
>
>If it is possible to feed the main bus using the alternate feed and loads
>are controlled by turning off items so that the battery is still up on
>arrival then the loss of the contactor would be a non issue as the items on
>the main bus would still be available at the airport.
It is possible to wire the airplane any way you wish. It's
an OBAM aircraft and subject only to your desires. I am
not clear as to what your concerns are for the existing design
but it doesn't matter. Please do whatever makes you the most
comfortable.
Bob . . .
Message 24
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| Subject: | Re: Engine Controls & Grounding |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 01:53 AM 12/6/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: Don Boardman <dboardm3@twcny.rr.com>
>
>Hi Bob and list.
>
>Bob in your book under note 5 you write: "make sure that jackets for engine
>controls do not ELECTRICALLY ground both a metal panel and the engine ...
>they can easily become a SECOND ground path on the wrong side of the
>airplane and create the same problems we're striving to eliminate.
>
>This was for airplanes with battery and engine on opposite ends of the
>airplane. I have the conventional engine on front, firewall, panel, battery
>under the passenger seat. Do I need to worry about insulating my throttle
>and prop controls from the metal panel?
Generally no. I can recall only once case where currents
circulating in controls jackets caused a problem and it was
with the compass. This is exceedingly rare.
>I will also have several other (8 ) push pulls on the panel operating in the
>engine compartment. Though none will be connected directly to the engine.
>(9 cyl radial M-14). Any concerns?
>
>Another point. In the engine compartment we are using all stainless steel
>braided hoses. Several of which run from the metal firewall bulkhead fitting
>to the engine. Any concerns?
>
>I am planning on having all electrical equipment grounds run to a instrument
>panel ground bus located on the firewall as per your book.
This will do fine.
Bob . . .
Message 25
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| Subject: | Re: Pitch Trim Motor Slowdown |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:34 PM 12/5/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "J. Oberst"
><joberst@cox-internet.com>
>
>I previously posted a question on how to cut down the speed of my 12V DC
>pitch trim motor. I got one response, which suggested I use the the
>Matronics Mark III adjustable speed governor. I have two issues with
>this... first, it is unclear to me what the current capacity of this unit is
>(does anyone know that? - I am not using MAC servos)... second, it looks
>like a bit of overkill, as I don't want adjustable speed, ground-actuation,
>multiple switches - just a permanent slowdown to one speed.
>
>Can anyone explain to me what the design goal is for a DC motor slowdown
>circuit? I've been told that a simple dropping resistor could cause the
>motor to overheat. Also, I don't want to do something to reduce the torque.
>Will a fixed voltage regulator do it, or does it need to be pulsed, or??
>
>Thanks.
>
>Jim Oberst
You got the long answer, let's look at your specific application.
What motor do you want to control and what system does it drive?
How have you deduced that you'll need to control the speed of this
motor? Have you put a power supply on the motor to see what
new voltage and current are required?
Bob . . .
Message 26
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| Subject: | Re: Myths and urban legends about motors |
--> AeroElectric-List message posted by: Jerzy Krasinski <krasinski@direcway.com>
>
> I've tried that with some success. As you've noted, it has to
> be "tuned" to individual system characteristics which makes
> it more difficult to offer plug-n-play spares for controllers
> and motors. I was having trouble too keeping the system stable
> over wide temperature ranges . . . the positive feedback would
> be sufficient to cause instability. This was 20+ years ago with
> mostly discrete components. Are you aware of any newer choices
> for hardware to implement this control philosophy?
>
> Bob . . .
>
>
>
>
This circuit was quite popular at some time, most of battery driven tape recorders
used it. Today, everything goes digital.
No, I did not see any integrated circuits for that application.
Jerzy
>
>
>
>
>
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