---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 12/07/03: 26 ---------------------------------------------------------- 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 _____________________________________ Time: 05:42:02 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: B&C 40 amp alternator : "F" tab? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 04:21 PM 12/6/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "Rick Fogerson" > >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 _____________________________________ Time: 05:42:28 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: B&C 40 amp alternator : "F" tab? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:41 PM 12/6/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Dan Checkoway" > >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 _____________________________________ Time: 06:18:21 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Myths and urban ledgends about motors --> AeroElectric-List message posted by: "Eric M. Jones" 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 _____________________________________ Time: 07:03:38 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Myths and urban ledgends about motors --> AeroElectric-List message posted by: "Paul Messinger" 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" Subject: AeroElectric-List: Myths and urban ledgends about motors > --> AeroElectric-List message posted by: "Eric M. Jones" > > 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 _____________________________________ Time: 07:15:21 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Using LEDs as aircraft beacons --> AeroElectric-List message posted by: "Eric M. Jones" 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 _____________________________________ Time: 07:32:45 AM PST US Subject: AeroElectric-List: SL 30 Intercom From: Gerry Holland --> AeroElectric-List message posted by: Gerry Holland 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 _____________________________________ Time: 07:58:52 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Myths and urban ledgends about motors --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:22 AM 12/7/2003 -0500, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >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 _____________________________________ Time: 08:37:17 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Myths and urban legends about motors --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:03 AM 12/7/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >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 _____________________________________ Time: 09:33:50 AM PST US From: Dave Morris Subject: Re: AeroElectric-List: Using LEDs as aircraft beacons --> AeroElectric-List message posted by: Dave Morris 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" > >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 ____________________________________ Time: 09:46:46 AM PST US From: "Brett Ferrell" Subject: Re: AeroElectric-List: Pitot Tube Wire --> AeroElectric-List message posted by: "Brett Ferrell" 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: 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" > > > > > >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 ____________________________________ Time: 11:47:57 AM PST US From: Jerzy Krasinski Subject: Re: AeroElectric-List: Myths and urban legends about motors --> AeroElectric-List message posted by: Jerzy Krasinski 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 ____________________________________ Time: 12:44:47 PM PST US From: RVEIGHTA@aol.com Subject: AeroElectric-List: 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 ____________________________________ Time: 01:36:17 PM PST US From: "Rhett Westerman" Subject: AeroElectric-List: OV Protection Module --> AeroElectric-List message posted by: "Rhett Westerman" 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 ____________________________________ Time: 04:14:01 PM PST US From: "Harold Kovac" Subject: Re: AeroElectric-List: NiMH batteries --> AeroElectric-List message posted by: "Harold Kovac" Try Radio Shack, expensive but they're there. ----- Original Message ----- From: 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 ____________________________________ Time: 05:07:00 PM PST US From: "Rick Fogerson" Subject: AeroElectric-List: Fw: B&C 40 amp alternator : "F" tab? --> AeroElectric-List message posted by: "Rick Fogerson" ----- 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 ____________________________________ Time: 05:36:59 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Fw: B&C 40 amp alternator : "F" tab? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:09 PM 12/7/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "Rick Fogerson" > > >----- 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 ____________________________________ Time: 05:42:09 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: microair wiring question --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" 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 ____________________________________ Time: 05:53:18 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Myths and urban legends about motors --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:09 PM 12/7/2003 -0600, you wrote: >--> AeroElectric-List message posted by: Jerzy Krasinski > > >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 ____________________________________ Time: 07:10:42 PM PST US From: "AI Nut" Subject: Re: AeroElectric-List: Reusing batteries --> AeroElectric-List message posted by: "AI Nut" Um, that made my head hurt. 8-) AI Nut ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Reusing batteries > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 11:31 PM 12/5/2003 -0500, you wrote: > >--> AeroElectric-List message posted by: "Fergus Kyle" > > > >" 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 ____________________________________ Time: 07:19:48 PM PST US From: "AI Nut" Subject: Re: AeroElectric-List: cooling fans, ONE DOLLAR --> AeroElectric-List message posted by: "AI Nut" How about the computer case fans? About $5, 12vdc, sturdy frame, and (usually) quiet. AI Nut ----- Original Message ----- From: "Dan Checkoway" Subject: AeroElectric-List: cooling fans, ONE DOLLAR > --> AeroElectric-List message posted by: "Dan Checkoway" > > 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 ____________________________________ Time: 08:42:27 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: OV Protection Module --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 03:36 PM 12/7/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "Rhett Westerman" > > >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 ____________________________________ Time: 08:52:39 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: NiMH batteries --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" 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 ____________________________________ Time: 08:57:16 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: To E-Buss or not To E-buss --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > > 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 ____________________________________ Time: 08:59:56 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Engine Controls & Grounding --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:53 AM 12/6/2003 -0500, you wrote: >--> AeroElectric-List message posted by: Don Boardman > >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 ____________________________________ Time: 09:02:39 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Pitch Trim Motor Slowdown --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:34 PM 12/5/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "J. Oberst" > > >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 ____________________________________ Time: 10:27:30 PM PST US From: Jerzy Krasinski Subject: Re: AeroElectric-List: Myths and urban legends about motors --> AeroElectric-List message posted by: Jerzy Krasinski > > 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 > > > > >