---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 10/18/03: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:47 AM - Re: External power receptacle (Eric M. Jones) 2. 06:59 AM - AWG (Jeff Deuchar) 3. 07:04 AM - Re: Bob, external power receptacle (Robert L. Nuckolls, III) 4. 08:00 AM - Re: thermistors for low fuel warning (Bob Kuc) 5. 08:37 AM - Re: AWG (Robert L. Nuckolls, III) 6. 09:10 AM - Re: AWG (Robinson, Chad) 7. 11:24 AM - Re: solar battery charger (Carl Coulter) 8. 11:53 AM - poor etiquette on my part (Carl Coulter) 9. 11:55 AM - Diodes (Steve Sampson) 10. 03:15 PM - Re: Re: RV-List: 4 conductor shielded wire for Dynon (Dan Checkoway) 11. 04:07 PM - (Eric M. Jones) 12. 06:18 PM - Re: thermistors for low fuel warning (Jim Sower) 13. 07:19 PM - Re: thermistors for low fuel warning (Bob Kuc) 14. 09:17 PM - Re: ProCrimper II Dies / Question (flmike) ________________________________ Message 1 _____________________________________ Time: 05:47:32 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: External power receptacle --> AeroElectric-List message posted by: "Eric M. Jones" From Najaco.com CESSNA "GROUND SERVICE PLUG RECEPTACLE A ground service plug receptacle permits the use of an external power source for cold-weather starting and during lengthy maintenance work on the electrical and avionics equipment. External power control circuitry is provided to prevent the external power and battery from being connected together during starting. The external power receptacle is installed on the left side of the engine compartment near the firewall. The ground service circuit incorporates polarity reversal and overvoltage protection. Power from the external power source will flow only if the ground service plug is correctly connected to the airplane. If the plug is accidentally connected backwards or the ground service voltage is too high, no power will flow to the electrical system, thereby preventing any damage to electrical equipment." So the center pin is also positive but with a diode or so to be read by the ground power unit. Eric ________________________________ Message 2 _____________________________________ Time: 06:59:10 AM PST US From: Jeff Deuchar Subject: AeroElectric-List: AWG --> AeroElectric-List message posted by: Jeff Deuchar Hello, I have a question about AWG. If I parallel two 26 AWG wires, what size of wire do I end up with? The reason I ask this strange question, is that I can get my hands on plenty of 26 guage wire, and was thinking I could pair it up? Thanks Jeff ________________________________ Message 3 _____________________________________ Time: 07:04:15 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Bob, external power receptacle --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:56 PM 10/17/2003 -0500, you wrote: >--> AeroElectric-List message posted by: Jerzy Krasinski > > >Bob, >I got a receptacle which is used commonly for connection to an external >battery if internal battery is week. I was told that the receptacle is >from a Cessna. I hoped for an easy installation but there are three >prongs there. Two big ones are described "+" (the central one), and >"-" (the side one). Unfortunately, there is a third one, smaller. No >description there, but there are two ~1A diodes connected to it, able >to conduct "from" the prong. There are two commonly used ground power receptacles in the wild. One is a Cole-Hersey product designed for over the road trucks and adapted to aircraft by Piper about 40 years ago. It's has be popularized as the "Piper style ground power jack." This is a simple, cylinder with outside shell as ground, and a single robust center pin as power. In the years BP (before Piper) the military and air transport communities developed a three terminal plug/socket combination which you have described. It's a military standard part used on many ground and air vehicle applications and is the connector of choice for most aircraft. >I would like to make the receptacle compatible with battery carts at >airports, so Cessna standard seems to be the right one. But how is the >third prong connected? Is it used to drive a relay or something? Consider what happens if you make or break a high current connection while energized. There is bound to be arcing that ultimately damages the contacts of the connector. The third pin is smaller (is sized only for mechanical robustness and carries only a few amps in operation) and shorter (connects AFTER the big guys are hooked up and disconnects BEFORE the big guys do). This pin is used to control a ground power contactor in the in a manner that makes sure that power cannot flow through the big pins while the connector is being mated or de-mated. Originally, this was the ONLY purpose for the small pin. Other features have been added over the years to include some components for ov and reverse polarity protection. I have illustrated wiring for both the Piper style and military style ground power jacks in an article at: http://www.aeroelectric.com/articles/grndpwr.pdf If it were my airplane, I'd go the "Piper" route. The military style is a pain in the arse to install. You need to fabricate your own door or mount it someplace where a door is not needed. The Piper style comes with its own door built in, is much easier to install, and probably lighter than the 3-pin connector installation. Another advantage of the Cole-Hersey connector is that you can have your own ground power jumper cables made up and it two is lighter than one using the fatter military style connector and a LOT less expensive. Bob . . . >I could not find anything on thet topic. I would appreciate your answer. >Thank you, >Jerzy > >Werner Schneider wrote: > > >--> AeroElectric-List message posted by: "Werner Schneider" > > > > >Interesting approach, would wonder what happens if you have a fuel injected > >engine with a return line (of "hot" fuel) back into the tanks. > > > >I'm using a optical device in my Glastar, works great and as it is LED it > >needs nearly no power!! > > > >http://www.ppavionics.com/LFL.htm > > > >Werner > > > >----- Original Message ----- > > > > > > > >>When the thermistor is immersed in fuel, the fuel keeps the thermistor > >>cooled off, the resistance remains high and the indicator light bulb does > >>not light up. > >> > >> > > > > > > > > > > Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 4 _____________________________________ Time: 08:00:52 AM PST US From: "Bob Kuc" Subject: Re: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: "Bob Kuc" > > Most of the 90's model Toyotas have them but you will most likely have to > order the entire fuel sending unit, about $280. > > On the other hand I found that everything mustang sells the thermistor > sensor for $32 > www.everythingmustang.com > I was following this approach one time ago. I went to a U-pull-it yard, and looked for all the import dashes for the low-level fuel light, and a fuel tank still there. With four bolts, and a philips, I dropped the tank and opened up the cover and removed the sensor. I ended pickup up three in one morning. $1 to get into the yard and the cost of the sensors, well, priceless. At one time, there were low level optical that were sold in the us. Can't remember the manufacturer. However, they discontinued them for another approach that would not work. However, I did pick up a few liquid level sensors from Australia via an "exchange" between builders. I am planning on using these refract low level sensors on my sump tanks. Bob --- ________________________________ Message 5 _____________________________________ Time: 08:37:45 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: AWG --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:58 AM 10/18/2003 -0700, you wrote: >--> AeroElectric-List message posted by: Jeff Deuchar > > > >Hello, > >I have a question about AWG. > >If I parallel two 26 AWG wires, what size of wire do I end up with? Wire cross-section doubles/halves for each three steps in AWG size. For example, 22AWG wire is 1/4 the cross section of 16AWG (6 steps away). As far as current carrying ability, there's a tiny advantage for say 3 22AWG wires carrying current as opposed to one 19AWG wire . . . the three wires dump heat better than a single strand of the same cross-section. >The reason I ask this strange question, is that I can get my hands on >plenty of >26 guage wire, and was thinking I could pair it up? Please don't do this. Wire is a trivial part of the expense of building your airplane. You have a lot of new things to learn in the proper use of tools and materials to do a good job. Some years from now, you're going to want to sell your airplane and it's my wish that you'll be proud of what you're offering to the next owner. Bob . . . ________________________________ Message 6 _____________________________________ Time: 09:10:19 AM PST US Subject: RE: AeroElectric-List: AWG From: "Robinson, Chad" --> AeroElectric-List message posted by: "Robinson, Chad" AWG sizes are biased on wire DIAMETER so you don't double that, as you can guess. Assuming a "perfect" wire, you get roughly the same resistance in both wires. The total resistance is 1/Rt = 1/(R1+R2), which for two identically-sized resistors (perfect wire) gives you half the initial resistance. That's gives you double the current capacity - about what you'd expect. My AWG table gives various current capacities depending on insulator type, number of strands, etc., which all affect heat dissipation. But if I take the lowest number I have 4A for one wire, and if I look for an 8A wire I get 22AWG. There are a few problems, of course. Because of the insulation the wires will be larger, so they might be harder to feed through a hole. You have to be careful about fusing because if either wire breaks or is cut somehow (or just not solidly terminated), you're actually protecting a 26AWG wire again, with only 4A of capacity, so it's easier to create situations where the wire gets too hot and starts a fire. Finally, because there's no such thing as a perfect wire (heck, even if you measure carefully the lengths might not be the same) one wire might carry more current than another (lower resistance) so you should probably "derate" their capacity a bit - maybe to 7.5A. (Actually it's nowhere near that much for short runs but...) Unless you have some vested reason to do so (such as if those wires are already run, and you're repurposing two of them to carry the current you need) you'd be better off with a single wire. Not to mention the complexity this creates in your wiring diagram. But there ARE valid reasons to do this and it CAN work if you're careful. Did I mess any of this up, Bob? Regards, Chad > -----Original Message----- > From: Jeff Deuchar [mailto:jdeuchar@telusplanet.net] > Sent: Saturday, October 18, 2003 9:58 AM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: AWG > > I have a question about AWG. > > If I parallel two 26 AWG wires, what size of wire do I end up with? > > The reason I ask this strange question, is that I can get my > hands on plenty of > 26 guage wire, and was thinking I could pair it up? ________________________________ Message 7 _____________________________________ Time: 11:24:43 AM PST US From: Carl Coulter Subject: AeroElectric-List: RE: solar battery charger --> AeroElectric-List message posted by: Carl Coulter Richard There are problems with just using a blocking diode, mainly over charging. I don't know what Harbor is selling. From your description, it is a kit for keeping bats charged and one would expect there to be a charge controller and blocking diode included. Should be, but then, for $10, maybe not. Could be the Harbor PV cells are small enough they can't overcharge the bat. In that case, the suggestions in the other replies for a diode are good ones. I would highly recommend a charge controller between the pv cells and the battery. The controller watches the battery voltage and shuts off the charge when the bat is full. All of the ones I have seen have a blocking diode in the circuit to prevent discharge when the cells are not putting out sufficient voltage - like every night. Also, some cells have a blocking diode at the cell. The cells I bought 5 years ago did. In my case, I wired around the diode in the cells cause I did not want the additional .6V drop, and the charge controller took care of any backfeed. There are a lot of controllers on the market. Most any outfit that deals with solar cells for remote cabins, RV, or marine applications have this stuff. They come in all sizes, complexity, and price. I bought a couple of pretty inexpensive ones for a cabin about three years ago and as I recall they were $20 or so. These were pretty dumb; three terminal potted device, no bat voltage adjustment. Try a Google search: solar cells charge controllers RV OR marine. I got about 8,000 hits. Most will be way to big for your application. But, there are small (read "inexpensive") units available. This one was $30 at http://www.oksolar.com/charge_controllers/sunsaver.htm Item#: 34931 SG4 Manufacturer: MorningStar 12VDC, 4.5A More Info $29.95 I'm not recommending it, it was just the first one I saw that looked like it would fit. I also don't know what size pv cell Harbor is selling. I would think the minimum you will need is 10 watts - that would be .6 Amps. Most are rated for available sun at noon-in June-in Arizona, so you won't even get that most days, but that would be a minimum. My guess is the cell will be 12" to 14" square to get that output. The guess is based on a statistical sample of one. The ones I bought five years ago are rated at 50W and are about 14" X 48". A lot of these sites will also have battery charging kits (pv cell and controller) available. But for 10+ watts, I think they will be in the $100 - $200 range. Building a system is feasible. You will need a blocking diode, voltage regulator, and bat voltage sensing - oh yeah, and a big enough cell. The trick is to keep the energy budget for the controller low, especially when the cells are off line. Solar cell applications generally don't have any energy to waste and the blocking diode may not stop all of the discharge (the voltage sensing circuit). Of course, one could put the sensing circuit on the controller side of the blocking diode and just compensate for the drop. Also, some of the current production controllers have a pulsed output. This supposedly makes the charger more efficient. These get more complicated. One has to measure the bat voltage between pulses. It takes a couple of bucks worth of silicon (microprocessor). This is out of my area of design expertise. I can probably do an 8.5X11 pencil sketch with a list of RS parts - no pulsed output, and it might even work. But, I'll bet Eric is your man for this. (You're welcome Eric ;-) I think you have a good idea. Happy charging and I hope you don't get gas ;-) (bad electrical engineering joke) Carl (haven't worked on my cabin in three years - airplane kit keeps sucking up the time) ********************** From: Richard May Subject: AeroElectric-List: solar battery charger I keep my plane in a T hanger that lacks electricity, I've purchased a couple of solar cell battery chargers from Harbor freight at $10 a piece andmounted them on the roof of my hanger. They work quite well, except that they give out after a few months of use. I connect one to the battery in my plane, and the other to the battery in my small tug to pull the airplane in and out of the hanger. I just recently read that they will discharge the battery at night or during cloudy days without a blocking diode. Does anyone know what type of diode to use for this purpose, and do I connect it to the positive or negative lead coming from the solar panel? Is there any type of device I could construct to prevent over-charging of batteries from Radio shack parts? ________________________________ Message 11 ____________________________________ Time: 10:51:37 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: solar battery charger --> AeroElectric-List message posted by: "Eric M. Jones" Subject: solar battery charger From: Richard May (ram45@comporium.net) >I've purchased a couple of solar cell battery chargers from Harbor freight at $10 a piece Make sure the cells put out a few volts more than the battery. You can put the cells in series just like batteries. >They work quite well, except that they give out after a few months of use. The Solar cells give out??? They should last forever. If the batteries give out they are probably suffering from never getting charged. >I just recently read that they will discharge the battery at night or during cloudy days >without a blocking diode. Does anyone know what type of diode to use for this purpose, and do >I connect it to the positive or negative lead coming from the solar panel? Use a 1N4001 to a 1N4007. Doesn't much matter. Use any "General Purpose" silicon diode. Attach it to the positive lead with the little silver band away from the solar cell. You can put it indoor going into the battery positive too. Little silver band goes towards the battery+. >Is there any type of device I could construct to prevent over-charging of >batteries from Radio shack parts? Yes. First buy a copy of "Forrest Mim's Engineer's Notebook" at Radio Shack . Then build a LM317 voltage regulator and adjust the output to whatever the battery's fully charged voltage should be. This won't do the fastest job but it will work well. You can forget about the diode if you take this route. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "Kitty Hawk Centennial---first heavier-than-air flight that didn't immediately crash" ________________________________ Message 12 ____________________________________ Time: 11:13:31 AM PST US Subject: Re: AeroElectric-List: solar battery charger From: caspainhower@aep.com 10/17/2003 02:13:13 PM --> AeroElectric-List message posted by: caspainhower@aep.com Does anyone know what type of diode to use for this purpose, and do I connect it to the positive or negative lead coming from the solar panel? A schottky diode is most commonly used, they drop ~.2 volts instead of the ~.6 volts of a standard diode. As long as they are properly biased it shouldn't matter which lead they are in. Craig S. ________________________________ Message 13 ____________________________________ Time: 11:56:34 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Transponder Main bus or Essential Bus --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:42 AM 10/17/2003 -0500, you wrote: >--> AeroElectric-List message posted by: John R > >:-) > >Also, I liked your change of name from "Essential" bus to "Endurance" >bus... if something is truly essential to continued flight, it should go >on the battery bus... > >-John It's certainly an advantage to reduce parts count between an "essential" item and its power source to reduce probability that use of that item will not be lost. However, if having but one such "essential" device puts probability of comfortable completion of flight at risk, then one should have a BACKUP for it. If every item capable of ruining your day has a BACKUP, then all of a sudden, it is NOT ESSENTIAL. It changes the way you can look at system design and truly achieve a system that is both essential and emergency free. Bob . . . ________________________________ Message 14 ____________________________________ Time: 11:57:00 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Strobe wire? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > >Check www.strobesnmore.com . He can sell you the Nova power supply and >cable by the foot. If you're using only 2 strobe heads the XPak 604 will do >the job for you. I know a lot of folks are using the 904 but with only 2 >heads that power supply (904) reduces the power output. This is not the >case with the 604. If you're using more than 2 flash tubes it's a mute >point. Just thought I'd pass it along. >Bill >Glasair SIIS-FT Great data point Bill, thanks! Bob . . . ________________________________ Message 15 ____________________________________ Time: 11:59:04 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: 10856 Wandke --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > >Comments/Questions: Wonder if I can use #4 cable to hook up a firewall >mounted battery to a Sky Tec starter on a new )235N2C(lower >compression). Using an Odyssey 680 battery in a Murphy Rebel. Sure . . . #4 is quite adequate to this task when the battery and engine are close together. I will invite you to join us on the AeroElectric List to continue this and similar discussions. It's useful to share the information with as many folks as possible. A further benefit can be realized with membership on the list. There are lots of technically capable folks on the list who can offer suggestions too. You can join at . . . http://www.matronics.com/subscribe/ Well considered and technically elegant answers to all of your questions are waiting for you there. Also, check out the downloadable materials at http://www.aeroelectric.com Thanks! Bob . . . |---------------------------------------------------| | A lie can travel half way around the world while | | the truth is till putting on its shoes . . . | | -Mark Twain- | |---------------------------------------------------| ________________________________ Message 16 ____________________________________ Time: 12:00:36 PM PST US From: jerb Subject: Re: AeroElectric-List: Re: Strobe wire? --> AeroElectric-List message posted by: jerb Rather than Nyloflo - get some of the light weight 1/2" tubing used for Mister or drip irrigation systems. One point does it need to be flame retardant, if so it may not qualify for this application. jerb snip.... > Consider this instead. If you buy a Whelan kit, it will come > with the wire. How about running a conduit of Nyloflo or > similar tubing from root to tip now. When you get your kit > later, it will be easy to run the wires in. > > ================================ ________________________________ Message 17 ____________________________________ Time: 12:14:10 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:23 AM 10/17/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "John Slade" > > > I'm using a optical device in my Glastar, works great and as it is LED it > > needs nearly no power!! > > > > http://www.ppavionics.com/LFL.htm > >$405 per tank ??? there has to be a less expensive way. I'd be interested in >learning more about that thermistor arrangement. Consider the Gemssenors p/n 143570 at: http://www.gemssensors.com/SpecTemplateStandard.asp?nProductGroupID=2 which can be had for $80 each and will drive a 40 ma lamp directly (plenty good for LED and you can find some 0.04A incandescent lamps too). Bob . . . ________________________________ Message 18 ____________________________________ Time: 12:23:43 PM PST US From: PTACKABURY@aol.com Subject: AeroElectric-List: Current Limiters --> AeroElectric-List message posted by: PTACKABURY@aol.com Bob: Help!! I am building a Lancair IV and am at the wire stringing stage. I have two 17 amp hour batteries and one 70 amp alternator. I have adopted a version of your Z-13 for the power distribution architecture, but can't figure out how many, where and what size current limiters I should use. Part of the problem is I can't read the diagrams in your book as the small print is fuzzy (and my eyes are on their sixth decade). So please tell me how to configure my current limiters. thanks and regards, paul ________________________________ Message 19 ____________________________________ Time: 01:40:09 PM PST US From: "Werner Schneider" Subject: Re: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: "Werner Schneider" What did you look at, one set is 115$ or 215$ a pair. Sure you can do it cheaper yourself, just you have to get two indicators with push to test (doing circuit test), two optical sensors , a circuit testing when the indicator fails etc. As you can see 4 wires are running between indicator and sensor for this purpose. Switch on current is a bit above 40ma, running on a bit over 20 ma for each sensor. As you've told you can make it cheaper, I found it value worth the money. It's up to everybody to decide by him/herself. And no I'm not in any way involved in PPA, just a happy customer =(;o) Werner ----- Original Message ----- From: "John Slade" Subject: RE: AeroElectric-List: thermistors for low fuel warning > --> AeroElectric-List message posted by: "John Slade" > > > I'm using a optical device in my Glastar, works great and as it is LED it > > needs nearly no power!! > > > > http://www.ppavionics.com/LFL.htm > > $405 per tank ??? there has to be a less expensive way. I'd be interested in > learning more about that thermistor arrangement. > John Slade > > ________________________________ Message 20 ____________________________________ Time: 01:41:30 PM PST US Subject: Re: AeroElectric-List: Current Limiters From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Paul, You can get fresh copies of all of the diagrams in the appendix by downloading the following .pdf file: http://www.aeroelectric.com/articles/Rev10/z10.pdf Regards, Matt- VE N34RD > --> AeroElectric-List message posted by: PTACKABURY@aol.com > > Bob: Help!! I am building a Lancair IV and am at the wire stringing > stage. I have two 17 amp hour batteries and one 70 amp alternator. I > have adopted a version of your Z-13 for the power distribution > architecture, but can't figure out how many, where and what size > current limiters I should use. Part of the problem is I can't read the > diagrams in your book as the small print is fuzzy (and my eyes are on > their sixth decade). So please tell me how to configure my current > limiters. thanks and regards, paul > > ________________________________ Message 21 ____________________________________ Time: 01:47:30 PM PST US From: Joa Harrison Subject: RE: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: Joa Harrison Anybody ran across an auto part number for an auto fuel tank? Joa --------------------------------- ________________________________ Message 22 ____________________________________ Time: 03:25:26 PM PST US From: "Trampas" Subject: RE: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: "Trampas" Most of the 90's model Toyotas have them but you will most likely have to order the entire fuel sending unit, about $280. On the other hand I found that everything mustang sells the thermistor sensor for $32 www.everythingmustang.com Everything Mustang's website is down, I found the price through goggle's cache. http://216.239.51.104/search?q=cache:GvfTUJyGVUEJ:www.everythingmustang.com/ Merchant2/merchant.mv%3FScreen%3DCTGY%26Store_Code%3DEM%26Category_Code%3DTH ERME+low+fuel+light+thermistor&hl=en&ie=UTF-8 Trampas -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Joa Harrison Subject: RE: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: Joa Harrison Anybody ran across an auto part number for an auto fuel tank? Joa --------------------------------- ________________________________ Message 23 ____________________________________ Time: 03:54:01 PM PST US From: Tom Brusehaver Subject: Re: AeroElectric-List: Transponder Main bus or Essential Bus --> AeroElectric-List message posted by: Tom Brusehaver Things could be better, with modern solid state transponders, but this is something that happened to me, with an older KT-76. During instrument training, we took off from FCM, in a Beech Sundowner. It was marginal VFR, and at 3000MSL there was an overcast. We were shooting my first approach for the day, VOR 11 at LVN, when approach called up and said they lost our transponder. Shocked my instructor said he'd look into it. He turned it off, then on, then pressed the CB, then fiddled and fiddled but the response light never came on. I went missed, called approach, and asked 'em anything on the transponder? They said nope. Can't well fly IFR in RADAR environment without a transponder, so we elected to head back to FCM (about 15min). During the trip, when the transponder was off, the ammeter showed almost no charge, with it on, a slight discharge. I cycled the master once, got about a 10AMP charge for about 2 seconds, then discharge. Could be the ammeter never really showed much of a discharge. Com/Nav Radios continued to work, but no-go on the transponder. We wouldn't have noticed the dead alternator, for a while, if approach wouldn't have told us they lost our transponder. Leave it on the essential buss, it could be a warning device if nothing else :-). Charlie Kuss wrote: > --> AeroElectric-List message posted by: Charlie Kuss > > Listers, > Which bus would you wire the Transponder to, and why? > Charlie Kuss > ________________________________ Message 24 ____________________________________ Time: 04:43:59 PM PST US From: jerb Subject: Re: AeroElectric-List: Need for relays? --> AeroElectric-List message posted by: jerb In most cases AC voltage/current rated switches normally will only carry a fraction of their AC rated current when used for DC current applications. The contacts are made of different material plus they use the zero crossing of the AC current to reduce contact burning/arcing when contacts are opened. Example a 5 Amp AC switch may only handle less than 100 mA of DC current. While some have improperly used them and gotten away with it for the time being, you'll never know when they will fail and fail prematurely. While AC rated switches may work fine for say for avionics switching for radios such as mike input or (logical level) feature control signals, any application carrying any amount of DC current more than 100 mA, use DC rated switches. They may cost a little more but lately I noticed there is getting to be less difference between the two. jerb At 04:30 PM 10/15/03 -0500, you wrote: >--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > >At 09:32 AM 10/15/2003 -0400, you wrote: > >--> AeroElectric-List message posted by: "Mark Banus" > > > >Bob, > > Just received plans for an engine install. It shows all switches with > > #22 wire going to relays (22 Relays). My understanding is that certain > > heavy loads (Pitot heat etc) need a relay as the switches can't handle > > the amps. But do I need relays for 3-10 amp circuits? More relays are > > more components to fail. I have looked at 125v 10 and 15 amp rocker > > switches from Digikey that look like they can handle the current. > > Pro/cons? Thanks\ > > Your switches will probably be just fine directly > switching the loads. See > http://www.aeroelectric.com/articles/swtchrat.pdf > > Bob . . . > > ________________________________ Message 25 ____________________________________ Time: 04:57:01 PM PST US From: Jerzy Krasinski Subject: AeroElectric-List: Bob, external power receptacle --> AeroElectric-List message posted by: Jerzy Krasinski Bob, I got a receptacle which is used commonly for connection to an external battery if internal battery is week. I was told that the receptacle is from a Cessna. I hoped for an easy installation but there are three prongs there. Two big ones are described "+" (the central one), and "-" (the side one). Unfortunately, there is a third one, smaller. No description there, but there are two ~1A diodes connected to it, able to conduct "from" the prong. I would like to make the receptacle compatible with battery carts at airports, so Cessna standard seems to be the right one. But how is the third prong connected? Is it used to drive a relay or something? I could not find anything on thet topic. I would appreciate your answer. Thank you, Jerzy Werner Schneider wrote: >--> AeroElectric-List message posted by: "Werner Schneider" > >Interesting approach, would wonder what happens if you have a fuel injected >engine with a return line (of "hot" fuel) back into the tanks. > >I'm using a optical device in my Glastar, works great and as it is LED it >needs nearly no power!! > >http://www.ppavionics.com/LFL.htm > >Werner > >----- Original Message ----- > > >>When the thermistor is immersed in fuel, the fuel keeps the thermistor >>cooled off, the resistance remains high and the indicator light bulb does >>not light up. >> >> > > ________________________________ Message 26 ____________________________________ Time: 10:45:31 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Need for relays? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:48 PM 10/17/2003 -0700, you wrote: >--> AeroElectric-List message posted by: jerb > >In most cases AC voltage/current rated switches normally will only carry a >fraction of their AC rated current when used for DC current >applications. The contacts are made of different material plus they use >the zero crossing of the AC current to reduce contact burning/arcing when >contacts are opened. Example a 5 Amp AC switch may only handle less than >100 mA of DC current. Not so. Relays are only slightly different than toggle switches in that their contact spreading velocities are not enhanced with over-center springs . . . but the ratio is not so great that any 5A relay needs to be de0rated to 100 ma. See > While some have improperly used them and gotten away >with it for the time being, you'll never know when they will fail and fail >prematurely. While AC rated switches may work fine for say for avionics >switching for radios such as mike input or (logical level) feature control >signals, any application carrying any amount of DC current more than 100 >mA, use DC rated switches. They may cost a little more but lately I >noticed there is getting to be less difference between the two. . . . simply not supported by engineering data from switch and relay manufacturers. See http://www.aeroelectric.com/articles/swtchrat.pdf for an exploration of switches . . . relays are not terribly different. If any one can cite manufacturer's data sheets for any control product be it switch or relay that suggests an AC/DC de-rating ratio this severe, I'd like to get a copy of it. Much of what's being circulated as valid common knowledge has roots in the RVator article I cited in my piece on switch ratings. The author badly mis-interpreted the Microswitch data sheets. These seeds have grown into forests of electro-whizzy folklore. The question that started this thread was posted by a reader who was pondering an airframe wiring diagram suggested by an engine supplier wherein the panel was sprinkled with something on the order of 20 switches all driving relays used to actually control loads. There is simply no justification for doing this. It drives parts count up, cost up, reliability down, and offers little if any useful improvement in performance. This system was crafted with little or no practical knowledge of designing for the elegant solution. So far, I've only seen photos of installed equipment. I'm waiting to see the remainder of the documentation before we attempt to comb the rats and tangles out of this badly over-built system. Bob . . . ________________________________ Message 27 ____________________________________ Time: 10:47:08 PM PST US From: kempthornes Subject: Re: AeroElectric-List: Need for relays? --> AeroElectric-List message posted by: kempthornes At 06:48 PM 10/17/2003 -0700, you wrote: >--> AeroElectric-List message posted by: jerb > >In most cases AC voltage/current rated switches normally will only carry a >fraction of their AC rated current when used for DC current >applications. I've been turning my electric fuel pump on and off with a micro toggle switch rated for AC with no explosions yet. Any day now tho, eh? >The contacts are made of different material plus they use >the zero crossing of the AC current to reduce contact burning/arcing My wife has so much trouble catching that brief little zero crossing that she just leaves lights on all over the house. K. H. (Hal) Kempthorne RV6-a N7HK - Three trips to OSH now. PRB (El Paso de Robles, CA) ________________________________ Message 8 _____________________________________ Time: 11:53:55 AM PST US From: Carl Coulter Subject: AeroElectric-List: poor etiquette on my part --> AeroElectric-List message posted by: Carl Coulter Whoops, I just replied to a message and did not deleted the digest test after the original message. Sorry, I promise I won't do it again. carl DO NOT ARCHIVE ________________________________ Message 9 _____________________________________ Time: 11:55:12 AM PST US From: "Steve Sampson" Subject: AeroElectric-List: Diodes --> AeroElectric-List message posted by: "Steve Sampson" Bob - I have looked back through the archives to see what diodes you reccomend and where to source them for the master / starter solenoids etc.. The IN4005 series at Radio Shack appears. Unfortunately, in the UK, Radio Shack is considerably less useful than ice skates in the Sahara. I have looked through the Farnell catalogue to see something that seems appropriate. Would the ST part BZW06-31 fit the bill? Sorry to ask such mundane questions. Steve. RV9a UK ________________________________ Message 10 ____________________________________ Time: 03:15:14 PM PST US From: "Dan Checkoway" Subject: Re: AeroElectric-List: Re: RV-List: 4 conductor shielded wire for Dynon --> AeroElectric-List message posted by: "Dan Checkoway" I never saw a response to this, and I'm just getting caught up on email... Dynon told me that the wires to the remote compass do NOT need to be shielded. In fact, they said it would be fine to use the shield of a shielded 3 conductor wire as the 4th conductor. That's from the horse's mouth. )_( Dan RV-7 N714D http://www.rvproject.com ----- Original Message ----- From: "Jeff Point" Subject: Re: AeroElectric-List: Re: RV-List: 4 conductor shielded wire for Dynon > --> AeroElectric-List message posted by: Jeff Point > > I just re-read the recently released, updated version of the > installation manual. It makes no reference to using shielded wire in > any part of the installation. I used 4 wire, 22ga shielded because I > was lucky enough to have some laying around. I would also like to know > if shielded wire is neccesary or even useful in this installation. > > Jeff Point > RV-6 panel, wiring > Milwaukee, WI > > Larry Bowen wrote: > > >--> AeroElectric-List message posted by: "Larry Bowen" > > > >So should it be assumed that the harness to the compass MUST be > >shielded? My harness was completed a couple months ago, but the compass > >(and radios) are not installed yet. Can I test if this is needed using > >the handheld? What would the procedure be? > > > >- > >Larry Bowen > >Larry@BowenAero.com > >http://BowenAero.com > > > > > > > > > >>-----Original Message----- > >>From: Sam Buchanan [mailto:sbuc@hiwaay.net] > >>Sent: Friday, October 03, 2003 3:55 PM > >>To: rv-list@matronics.com > >>Subject: AeroElectric-List: Re: RV-List: 4 conductor shielded > >>wire for Dynon > >> > >> > >>--> AeroElectric-List message posted by: Sam Buchanan > >> > >> > >> > >>DJB6A@cs.com wrote: > >> > >> > >>>--> RV-List message posted by: DJB6A@cs.com > >>> > >>>To all, > >>> > >>>For those of you (like me) who have been searching for 4 > >>> > >>> > >>conductor 22 > >> > >> > >>>gauge shielded wire for your remote mounted Dynon > >>> > >>> > >>Magnetometer, Wicks > >> > >> > >>>aircraft has special ordered 500 ft. You will need to let > >>> > >>> > >>them know it > >> > >> > >>>is not in the catalogue. They expect it in next week. They > >>> > >>> > >>will add it > >> > >> > >>>as a permanent item if there is a demand for it. > >>> > >>>Regards, > >>>Dave Burnham > >>>RV6A (N64FN) > >>> > >>> > >>Be sure you check your local electrical cable suppliers. I > >>found a nearby outlet that had the four conductor 22g > >>shielded cable for $0.45/ft. > >> > >>Sam Buchanan > >> > >> > > > > > > > > > > ________________________________ Message 11 ____________________________________ Time: 04:07:39 PM PST US From: "Eric M. Jones" Subject: AeroElectric-List: --> AeroElectric-List message posted by: "Eric M. Jones" I hope Bob doesn't mind my butting in. Steve: Remarkably, the ST BZW06-31 won't do. Farnell in the UK (Newark in the US) has billions and billions of 1N4005. If they are sold out use a 1N4004, or 5, or 6, or 7. Easy to get. By the Way that's ONE-N4004! The brief specs you need are: Diode, Rectifier, General Purpose, Case DO-41 (or just anything with leads), Current 1A (minimum), Reverse voltage, 50V (minimum...get the 100V). Don't let the choices baffle you. We live in a world of bewildering abundance. Eric ________________________________ Message 12 ____________________________________ Time: 06:18:26 PM PST US From: Jim Sower Subject: Re: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: Jim Sower Bob, How do you connect them, say, to light a little Radio Shack LED on the panel? Is it easy, or do you have to know something and do something besides connect them all in series? Inquiring minds need to know .... Jim S. Bob Kuc wrote: > With four bolts, and a philips, I dropped the tank and > opened up the cover and removed the sensor. I ended pickup up three in one > morning. $1 to get into the yard and the cost of the sensors, well, > priceless. ________________________________ Message 13 ____________________________________ Time: 07:19:11 PM PST US From: "Bob Kuc" Subject: Re: AeroElectric-List: thermistors for low fuel warning --> AeroElectric-List message posted by: "Bob Kuc" Jim, I bench tested these sensors. You feed them 12 volts. When they are in fuel the resistance is so high that the LED will not light. When it is out of fuel the led lights up. It has been a while, I do not remember if I had a resister in line or not. I do not believe so. It should be easy to test. Just get a jar of fuel and with a volt meter, you can see how much you get out. As a side note. IF one of those sensors are in the bottom of the fuel tank or in the sump, and the sensor is in water, there is some voltage, but not as mush as fuel, that goes through the sensor and dimly lights the led, so one could be used as a water detector. Again, just filling a jar up with fuel and then adding water, you could check the voltage. As I write this, it could be that at the time I was testing this, I was using the lights that were on the dashboard of the cars. So they could be 12v lamps instead of LEDS. If that would be the case, then a resistor would be needed. You could also probably feed them 5 volts though those sensors also. Bob The liquid sensors that I plan on using on the sumps were made by Honeywell, but again they are not made in the US. For my fuel tank, I am planning on putting a T in the hose from the main to my sumps. This T would act like a standpipe that I can attach a variable voltage fuel sensor. All this will be attached to a PIC that would interpret the voltages or the on/off of the optical fuel level sensor and light up the appropriate level bar graph. > How do you connect them, say, to light a little Radio Shack LED on the panel? > Is it easy, or do you have to know something and do something besides connect > them all in series? > > > With four bolts, and a philips, I dropped the tank and > > opened up the cover and removed the sensor. I ended pickup up three in one > > morning. $1 to get into the yard and the cost of the sensors, well, > > priceless. --- ________________________________ Message 14 ____________________________________ Time: 09:17:50 PM PST US From: flmike Subject: AeroElectric-List: Re: ProCrimper II Dies / Question --> AeroElectric-List message posted by: flmike Dwight, For the BNC's, I believe you want die set, p/n 58436-1. That should give you a nice hex crimp for RG-58 or RG-142 coax. Think it's $42 at Digikey. If you want an "O" style crimp, the p/n is 58435-1. The 82074 number you mentioned is the coax connector catalog. For the machined D-sub pins, I'd go with the four-way crimp tool that B & C or one of the other suppliers sells rather than a die set for the Pro-Crimper. Or a Daniels AFM8 with the right positioner if you can find one cheap. The other die set you might want for the Pro-Crimper is one for the Amp / Tyco Mate-n-loc pins used on the strobe connectors. That would be die set p/n 90575-2. But, this die set is NOT cheap, like $100. Hard to justify for one project, but it does make a beautiful crimp. Mike __________________________________