---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 05/24/03: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:23 AM - However (Fergus Kyle) 2. 07:32 AM - Ground is ground? (Fergus Kyle) 3. 12:26 PM - Re: Electric Bob-Battery Contacter and (Robert L. Nuckolls, III) 4. 12:40 PM - Two questions-- (Eric M. Jones) 5. 01:51 PM - Re: RFI and Grounds... (Robert L. Nuckolls, III) 6. 10:19 PM - Re: Two questions-- (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 07:23:38 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: However --> AeroElectric-List message posted by: "Fergus Kyle" "--> AeroElectric-List message posted by: Charles Brame --> 90 degree BNC Connectors would make my antenna connections easier and more hidden. Do such critters exist? Is there a reasonable source for 90 connectors?Any pros or cons to their use? Charlie RV-6A N11CBSan Antonio" Remember, Charlie, No offence, but if you're not familiar with coaxial cable and its connectors, [a] You are interested in 50 ohm connectors only, to match cable,[b] Your primary cable is RG58, RG 400 or similar (for size), and [c] You may want to study and practice attaching connectors to coax cable because (1) it's not simple, and (2) 95% of antenna trouble is found in the connectors, especially after a while unles properly done. Happy hunting, Ferg Europa A064 ________________________________ Message 2 _____________________________________ Time: 07:32:11 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: Ground is ground? --> AeroElectric-List message posted by: "Fergus Kyle" "> --> AeroElectric-List message posted by: Scott Bilinski > > This brings up a question I have been thinking about for a while now and> that is, Isnt ground, ground?" Scott, The simple answer is "No, it's not". "In the case of a metal airplane the whole> thing is a ground. How does it matter where things are grounded? Isnt it> all the same?" The ideal answer is: "--> AeroElectric-List message posted by: Duncan McBride You are a perfect candidate for the Book. See http://www.aeroelectric.com/ and buy Bob Nuckoll's book. It has answered a hundred questions such as yours, and knowing it's on the shelf makes me feel a little less guilty for the help I get on this list" Happy Landings, Ferg ________________________________ Message 3 _____________________________________ Time: 12:26:24 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Electric Bob-Battery Contacter and Relay Questions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:11 PM 5/23/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "Rick Fogerson" > >Hi Bob, >Re the B&C battery contactor: Your wiring diagrams seem to indicate that a >diode goes between the Battery post and the smaller terminal closest to >it. My contactors actually have a plain wire jumper between the Battery >post and the smaller terminal closest to it and the diode wired between >the two small terminals. Is is this correct? see http://www.aeroelectric.com/Catalog/switch/switch.html#s701-1 and http://www.aeroelectric.com/Catalog/switch/s701-1l.jpg >Re the S704-1 relay (used to switch power for >7A power when batterys are >located in the rear): Does it matter which one of the two solenoid >terminals that power is hooked to? The one closest to the com terminal or >the one below it? no >Also, your wiring diagram for the relays shows the NO terminal jumpered to >a solenoid terminal and the two solenoid terminals connected with a 1N4005 >diode. Are these external jumpers and diodes that I have to add or are >these internal to the relay? they are external See http://www.aeroelectric.com/articles/s704inst.jpg Bob . . . ________________________________ Message 4 _____________________________________ Time: 12:40:35 PM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Two questions-- --> AeroElectric-List message posted by: "Eric M. Jones" 1) Along with keyswitch orientation. How about the little keyway on the toggle switch bushing. I always put them on the OFF/Down side. Is there a standard I don't know about? 2) Is there anyone kind enough to send me a copy of DO-160. I don't have the membership dues right now but I promise to join when I can. Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "Mankind faces a cross-roads. One path leads to despair and utter hopelessness. The other, to total extinction. Let us pray we have the wisdom to choose correctly." --Woody Allen ________________________________ Message 5 _____________________________________ Time: 01:51:23 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RFI and Grounds... --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:47 PM 5/23/2003 -0500, you wrote: >--> AeroElectric-List message posted by: Canyon > >Scott Bilinski wrote: > >This brings up a question I have been thinking about for a while now and > >that is, Isnt ground, ground? In the case of a metal airplane the whole > >thing is a ground. How does it matter where things are grounded? Isnt it > >all the same? >--- >Not trying to play games here -- simply proposing a couple things to >ponder. I have trained many ETs through the years and their training >all started with a couple simple ideas to ponder. > >1. Is there any such thing as a short circuit? This is a common term in the vernacular of many disciplines. In the airplane business, it's more often referred to has a "hard fault" . . . but irrespective of vernacular and venue it's understood to be an unwanted conduction path producing current flows in potentially hazardous ways. They often exceed the path's rated current capability by many times. A hard fault on a bizjet's ni-cad can get you several thousands of amps "short circuit", "hard fault" or any thing else one chooses to call it. The only limitation on potential current flow in a hard fault are path resistances which cannot be (except in a super conduction environment) zero ohms. 2,000A from a 24V battery suggests a path resistance of 12 milliohms which has to include internal resistance of the battery and all other conductors (including ground) that are part of the closed loop. >2. Can two wires occupying the same physical space and carrying equal >currents of opposite polarity radiate energy externally? A theoretical hypothesis at best but assuming you could twist a couple of 80AWG wires together without breaking them and drive them as closed loop, the magnetic field around the pair would be exceedingly low . . . but probably not zero. Bob . . . -------------------------------------------- ( Knowing about a thing is different than ) ( understanding it. One can know a lot ) ( and still understand nothing. ) ( C.F. Kettering ) -------------------------------------------- ________________________________ Message 6 _____________________________________ Time: 10:19:01 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Two questions-- --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 03:43 PM 5/24/2003 -0400, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >1) Along with keyswitch orientation. How about the little keyway on the >toggle switch bushing. I always put them on the OFF/Down side. Is there a >standard I don't know about? Our diagram numbers assume key-way up. Of course, this only affects the progressive transfer switches. All others are mirror image for operation and can mount either way. >2) Is there anyone kind enough to send me a copy of DO-160. I don't have >the membership dues right now but I promise to join when I can. DO-160 is a 3-ring binder of some magnitude . . . it's several hundred pages I think. I'm trying to track down a .pdf version but no luck so far. Bob . . .