---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 11/15/23: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 0. 01:47 PM - A List Contribution - It's Your Personal Squelch Button... (Matt Dralle) 1. 09:40 AM - Re: bad fuses (Robert L. Nuckolls, III) 2. 02:10 PM - Re: Re: bad fuses (Matthew S. Whiting) 3. 02:29 PM - Power, signal, and Coax - How should they be bundled? (wsimpso1) 4. 06:17 PM - Re: Power, signal, and Coax - How should they be bundled? (Robert L. Nuckolls, III) ________________________________ Message 0 _____________________________________ Time: 01:47:06 PM PST US From: Matt Dralle Subject: AeroElectric-List: A List Contribution - It's Your Personal Squelch Button... There is an automatic "squelch button" of sorts for the Fund Raiser messages. Here's how it works... 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The system keys on the given email address and since most of these are anonymous public access methods, there is no simple way to filter them. ] ________________________________ Message 1 _____________________________________ Time: 09:40:27 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: re: bad fuses Received my amazon order of 'cheap fuses'. Don't have time to gather fine-grained data right now but just for grins: Connected a 2A fuse directly across a CV/CC power supply set up for 24v @ 5A. Turned on power supply and got tired of waiting for the fuse to blow after a minute or so. Increased to 10A and repeated test. Took video of the results. Fuse blew in ~400 milliseconds. Okay, would we wire a 2A circuit with anything less that 22AWG? I wouldn't. I demonstrated 22AWG ability to carry 20A for an indefinite interval without putting the insulation at risk. http://aeroelectric.com/Pictures/Wire/22AWG_20A.pdf Yeah, this fuse is a bit more robust than a name-brand device . . . but would it put a 22AWG feeder at risk? Need to build some instrumentation support shelves over the workbench before I can set up a really good examination of these devices. Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ In the interest of creative evolution of the-best-we-know-how-to-do based on physics and good practice. ________________________________ Message 2 _____________________________________ Time: 02:10:15 PM PST US From: "Matthew S. Whiting" Subject: Re: AeroElectric-List: re: bad fuses Yes, one wire in room temp air will carry a fair bit of current. However, b undle a few wires at 12,000 feet and the capacity will be a fair bit less. It is good the fuse blew at 10 A. I have seen videos of 2 A Chinese fuses t hat carried 30 A for a fair bit of time. Some Chinese fuses MAY protect wire adequately, but in my airplane I want fu ses that WILL protect my wires adequately. Matt Sent from my iPad > On Nov 15, 2023, at 12:42=AFPM, Robert L. Nuckolls, III wrote: > > =EF=BB Received my amazon order of 'cheap fuses'. Don't have time > to gather fine-grained data right now but just for grins: > > Connected a 2A fuse directly across a CV/CC power supply > set up for 24v @ 5A. Turned on power supply and got tired > of waiting for the fuse to blow after a minute or so. > > Increased to 10A and repeated test. Took video of the > results. Fuse blew in ~400 milliseconds. Okay, > would we wire a 2A circuit with anything less that > 22AWG? I wouldn't. I demonstrated 22AWG ability > to carry 20A for an indefinite interval without > putting the insulation at risk. > > http://aeroelectric.com/Pictures/Wire/22AWG_20A.pdf > > Yeah, this fuse is a bit more robust than a > name-brand device . . . but would it put a 22AWG > feeder at risk? > > Need to build some instrumentation support shelves > over the workbench before I can set up a really > good examination of these devices. > > Bob . . . > > //// > (o o) > ===========o00o=(_)=o00o======= = > < Go ahead, make my day . . . > > < show me where I'm wrong. > > ======================== ======== > > In the interest of creative evolution > of the-best-we-know-how-to-do based > on physics and good practice. ________________________________ Message 3 _____________________________________ Time: 02:29:56 PM PST US Subject: AeroElectric-List: Power, signal, and Coax - How should they be bundled? From: "wsimpso1" Here is my little problem. I am trying to wire my fiberglass airplane with internal antennas properly. I have little insight on electromagnetic compatibility. Please help. I know that I am supposed to keep wiring for DC power to stuff like motors and electronics separated from data, but am struggling with knowing what is what and how much they matter. So first issue is we are supposed to keep DC power separated from signal lines. I know which are power and which are data, and I know which are coax resonating at RF frequencies. What do I with coax? I have three antennas back there with cables going forward and another antenna going a foot or so to the ELT box. Here is what we have in the aft fuselage: Position signal from my trim servos is data. The maker puts the two power wires to an electric motor and three wires for servo position on the same cable with no shielding. Five wires 24AWG, with a max 1 amp for power. Three sets of these; ELT, has power and GPS position data signal, all 22 AWG, 1 amp fuse, plus an RJ11 connector cable to the control box forward. No motors, just electronics; Three coax antenna cables, two TX/RX for COM, One RX for GS; LED continuous and flashing - continuous 1 amp and momentary 6 amp, and recommend shield grounded at airframe ground. So, how do I bundle this stuff to stay quiet on signal and radios? Do we consider antenna coax to be power or signal or a third category? Does it work OK to bundle coax with power wires? Or will electric motors mess up the Voice and GS stuff? The makers of the servos and ELT seem to bundle up power and signal will they be OK if I keep them that way or is it way better to separate power from signals as close to the servos as I can, run power together then bundle signals together and run them separately? Do I run coax cables together but away from a power bundle for ELT and LED and servos and away from signal bundles? I have a dipole on each fuselage wall that tends to use the whole vertical height available. I plan to run my wiring along the fuselage walls and through the center of the dipoles. That gives me a place for two bundles. Putting a third bundle at say top or bottom of the fuselage has been warned against - Jim Weir says it will mess with my COM antennas. I could suspend a run of wiring down the middle of the fuselage, next to the big push-pull tube for the elevators. That only gets me about 4 separation between center and sides with three bundles and would get interesting to work the support. A fiberglass wand supported at bulkheads and a some triads along the length. I do not have any desire to do that It all gets more interesting as we go forward, but the answers to the above questions should help with insight. The only antennas from the baggage bay through the cockpit are transponder and ADS-B on the floor with their own ground planes and two GPS antennas at the top of the roof that need no ground planes. I still only have two paths around the seats, so I suspect I must decide if my signals from the trim servos can be bundled up with the power wires or the coax. My center console is really crowded as we pass over the spar. Maybe I could run the signal bundle outside the console and put a cover over it. Ugh. What say you guys? It sure would help if I can bundle the servo position signals with either the power wires or with the coax cables and still have it behave nicely. Billski Read this topic online here: http://forums.matronics.com/viewtopic.php?p=512304#512304 ________________________________ Message 4 _____________________________________ Time: 06:17:24 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Power, signal, and Coax - How should they be bundled? At 04:29 PM 11/15/2023, you wrote: > >Here is my little problem. I am trying to wire my fiberglass >airplane with internal antennas properly. I have little insight on >electromagnetic compatibility. Please help. > >I know that I am supposed to keep wiring for DC power to stuff like >motors and electronics separated from data, but am struggling with >knowing what is what and how much they matter. Not true. "Data" carried on RS or CAN style serial signals are DESIGNED to live happily with other energy paths in a complex system. That's what good data management is all about . . . if a product is qualified to go into an airplane, it is assumed to be TESTED per some agreed upon protocol for RESISTANCE to EXPECTED antagonists. I worked in general aviation electrical/avionics systems for 40 plus years. Not once did I encounter a situation where the manufacturer warned against routing any of their products wiring separate from any other wires in the airplane. To do so would be a written admission of their failure to design a product INCOMPATIBLE with their target market. Same thing goes for cars, over the road trucks, all manner of heavy machines. High speed data systems are EVERYWHERE. Do installation instructions for any accessories proposed for use in your project include such warnings? Yeah, flux gates are a special case cause they're task is to resolve VERY TINY angular position of earth's magnetic field. But signal paths out to the flux gate should require no special treatment for electro-magnetic compatibility with the rest of ship's systems. Throughout my experience in experimental aviation, I've encountered several instances where a product was adversely affected by radio frequency energy from transmitters. Poorly designed products. On the certified side of the house, I had a case on Hawker-Beech 800 aircraft where a poorly conceived HF antenna caused a gross failure of every starter generator controller in the airplane. Turns out that the 30+ year old controllers were grand-fathered onto current production never having been qualified to ANY reasonable compatibility requirements! Spent a week in Little Rock getting some brand new aircraft sold off before a Dec 31 deadline to meed sales targets! Man . . . that was a can of worms! Bottom line is that much of what's circulated as sage advice for configuring wire bundles in your project is not founded in good engineering or physics. Ignore it. Concentrate on good craftsmanship and don't worry about things that go squeak and bump in the night. Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ In the interest of creative evolution of the-best-we-know-how-to-do based on physics and good practice. ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.