---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 04/10/11: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:15 AM - Brock Carburetor Heat Valve (Harley) 2. 10:34 AM - avionics ground question (B Tomm) 3. 10:46 AM - heavy wire question (B Tomm) 4. 11:32 AM - Re: avionics ground question (Robert L. Nuckolls, III) 5. 11:37 AM - Re: heavy wire question (Charlie England) 6. 11:45 AM - Re: heavy wire question (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:15:26 AM PST US From: Harley Subject: AeroElectric-List: Brock Carburetor Heat Valve All... Since I now have a ram air box with a built in carburetor heat valve, I won't be installing the Ken Brock carb heat valve that I had previously purchased for my Long EZ. So, I have it on eBay right now for the next ten days. Never used or installed, like new, no reserve, with the 3 page installation plans. The same unit (Brock/Rutan part number VECHVA) is currently being sold on Aircraft Spruce for $115 (Aircraft Spruce number 01-00845). Since it mounts on the firewall, with air hoses to the carburetor, it is not specific to any engine or plane and is currently being used with many four cylinder engines, both tractor and pusher, on hundreds of Long-EZs, Variezes, Cozy's and so forth. Also included are plans to construct a cabin heat valve. You can see it here: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=350454427697 In case the above link wraps, here's it's tinyurl: http://tinyurl.com/3qwpp2h Harley ________________________________ Message 2 _____________________________________ Time: 10:34:57 AM PST US From: "B Tomm" Subject: AeroElectric-List: avionics ground question Basically I'm using a single point pass-through ground on the firewall. However, I also have a forest of tabs for an avionics ground (for convenience) located nearby which will be connected to the main ground with either 5 awg20 ala Bob's drawings or a single 12awg wire. The aircraft is an RV7 so the avionics ground will be bolted to a metal structure. This mounting method will naturally provide a secondary ground path back to the single point ground. My question is should this avionics ground be insulated from the metal structure that it's bolted to, to eliminate a possible ground loop or at least to ensure that the electrons find their way back to the single point ground via the intended wire rather than some willy nilly path through the structure? or does it matter? Bevan ________________________________ Message 3 _____________________________________ Time: 10:46:54 AM PST US From: "B Tomm" Subject: AeroElectric-List: heavy wire question Think Z-13 here but other architectures probably apply. The battery is connected to the contactor in this case with a 2awg wire. The battery is also connected directly to the battery buss with a much smaller wire, say 14awg. What is the best practical way to connect two wires to the same terminal of the contactor? Two crimp connectors (ring terminal) do not seem to fit well together on the terminal ( I want the terminals covered with those silicone boots too). I would like to crimp the two wires inside the same crimp terminal but they won't both fit. Should I cut some of the strands off the larger wire to make room for the smaller wire? The next size crimp connector looks a little bit too large to accommodate both wires but I could "over-crimp" until they are very snug but the connector looks a little mashed. Which is the best way to connect two dissimilar sized wires to the same terminal? I have a similar application on the "out" side of the contactor where a 6awg wire is to connect with a 2awg wire on the same terminal. Looking for a reliable, simple and elegant solution. Thanks. Bevan ________________________________ Message 4 _____________________________________ Time: 11:32:03 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: avionics ground question At 01:30 PM 4/10/2011, you wrote: >Basically I'm using a single point pass-through ground on the >firewall. However, I also have a forest of tabs for an avionics >ground (for convenience) located nearby which will be connected to >the main ground with either 5 awg20 ala Bob's drawings or a single >12awg wire. The aircraft is an RV7 so the avionics ground will be >bolted to a metal structure. This mounting method will naturally >provide a secondary ground path back to the single point ground. > >My question is should this avionics ground be insulated from the >metal structure that it's bolted to, to eliminate a possible ground >loop or at least to ensure that the electrons find their way back to >the single point ground via the intended wire rather than some willy >nilly path through the structure? or does it matter? This isn't so much a matter of 'wiring' as it is a matter of locations. A panel ground bus is located on the panel with the closest practical proximity to the potential victims of ground induced noises. Have all potential victims share a single ground point with other non-antagonists on the panel is a prophylactic against ground loops. When all roads lead straight to Rome, there are no shortcuts for unwelcome noise coupling events to form up. It doesn't matter how THAT ground point gets grounded, its a matter of WHO USES that ground point. The 37-pin panel ground bus we offer is insulated from local ground . . . but it's not necessary that it BE isolated. Bob . . . ________________________________ Message 5 _____________________________________ Time: 11:37:43 AM PST US From: Charlie England Subject: Re: AeroElectric-List: heavy wire question On 4/10/2011 12:43 PM, B Tomm wrote: > Think Z-13 here but other architectures probably apply. > The battery is connected to the contactor in this case with a 2awg > wire. The battery is also connected directly to the battery buss with > a much smaller wire, say 14awg. > What is the best practical way to connect two wires to the same > terminal of the contactor? Two crimp connectors (ring terminal) do > not seem to fit well together on the terminal ( I want the terminals > covered with those silicone boots too). I would like to crimp the two > wires inside the same crimp terminal but they won't both fit. Should > I cut some of the strands off the larger wire to make room for the > smaller wire? The next size crimp connector looks a little bit too > large to accommodate both wires but I could "over-crimp" until they > are very snug but the connector looks a little mashed. Which is the > best way to connect two dissimilar sized wires to the same terminal? > I have a similar application on the "out" side of the contactor where > a 6awg wire is to connect with a 2awg wire on the same terminal. > Looking for a reliable, simple and elegant solution. > Thanks. > Bevan If you crimp both in the next larger connector, you can fill the next-larger connector with scrap wire(s) before crimping, then clip off the excess scrap. Avoids reducing the current capacity of the larger wire, & enables a 'normal' crimp. Charlie ________________________________ Message 6 _____________________________________ Time: 11:45:24 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: heavy wire question At 01:43 PM 4/10/2011, you wrote: >Think Z-13 here but other architectures probably apply. > >The battery is connected to the contactor in this case with a 2awg >wire. The battery is also connected directly to the battery buss >with a much smaller wire, say 14awg. > >What is the best practical way to connect two wires to the same >terminal of the contactor? Two crimp connectors (ring terminal) do >not seem to fit well together on the terminal ( I want the terminals >covered with those silicone boots too). I would like to crimp the >two wires inside the same crimp terminal but they won't both >fit. Should I cut some of the strands off the larger wire to make >room for the smaller wire? The next size crimp connector looks a >little bit too large to accommodate both wires but I could >"over-crimp" until they are very snug but the connector looks a >little mashed. Which is the best way to connect two dissimilar sized >wires to the same terminal? > >I have a similar application on the "out" side of the contactor >where a 6awg wire is to connect with a 2awg wire on the same >terminal. Looking for a reliable, simple and elegant solution. Using contactors with longer studs is the general fix. When I was selling the S701-1 Emacs! I shipped it with thin, brass top-nuts but even with the standard nut, the RBM/Stancor part had a longer stud than the Cole-Hersey parts . . . and would generally take up to 3 terminals. Contactor posts are indeed preferred fan out points for distribution of power but dealing with the short studs on some contactors is problematic. If push comes to shove, you can replace the bottom nut with a thin "jam nut" and get some more exposed stud. This is less risky with modern versions of these parts. Emacs! The internal contact surface is held in better alignment by bosses on the molded insulator. I may have a quantity of these nuts left over from those times. I'll dig around in the moving boxes as yet unpacked. Bob . . . ------------------------------------------------------------------------------------- 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.