---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 02/05/23: 3 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:36 AM - Re: Primary Power Diagram RV-14 (Mudfly) 2. 12:48 PM - Re: Master Relay Typical Resistance (long Story) (Robert L. Nuckolls, III) 3. 12:55 PM - Re: Replacing copper bar with tefzel wire (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:36:47 AM PST US Subject: AeroElectric-List: Re: Primary Power Diagram RV-14 From: "Mudfly" Small changes to the Primary Power System diagram. Also added interconnect drawing for STBY Batteries. Upated drawings attached. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=510122#510122 Attachments: http://forums.matronics.com//files/stby_batts_interconnect_drawing_824.pdf http://forums.matronics.com//files/primary_power_system_948.pdf ________________________________ Message 2 _____________________________________ Time: 12:48:30 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Master Relay Typical Resistance (long Story) At 09:48 AM 2/2/2023, you wrote: >Is the master contactor physically hot after extended use? Might hold a clue? A typical battery master contactor (Metal, 'whisky' barrel') will start out cold with a current draw on the order of 0.8A and drop to somewhere around 0.6A after it warms up . . . and warm up it will. 0.6A at 14.5V is right at 9 Watts. In time, this will raise the device temperature to something on the order of 170F in still, room-temperature air. It will probably not be nearly that warm in your airplane. Hence, continuous operation current will be a bit HIGHER than 0.6A. Nonetheless, a NORMALLY operating contactor will be too hot to touch. This is a GOOD thing. Your contactor IS mounted cap-down and has an itty- bitty drain hole in the cap? Warm ops go to drying out the contactor's innards thus extending its service life. If voltage drop across the contactor's power path is over 100 mV or so . . . and especially if it VARIES with vibrational stimulus (rap it with the handle of a screwdriver), the contacts are AGED and the device should be replaced. This basket carries a LOT of the systems 'eggs' but they're cheap. You'll spend more $time$ fussing over its diagnosis than the thing costs. When in doubt, replace it. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 3 _____________________________________ Time: 12:55:49 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Replacing copper bar with tefzel wire At 09:47 PM 2/3/2023, you wrote: > >I am building a Vans RV7 , IO360, Z101, using >B&C master and starter contactors, and an EarthX >ETX 900 battery. I can=99t easily use the Vans >design solution of 0.125=9D thick copper bar, >about 3=9D long x 0.5=9D wide, to connect the >master solenoid to the starter solenoid, due to >physical placement on my firewall and the stud >orientation on the B&C starter contactor. So I >want to use an insulated wire instead of the bar, maybe only 4=9D or so. > > >From old posts on vansAirforce.net forum, the > current here is estimated to be up to 320 amps > for short periods while cranking the starter. > Is that correct? What gauge tefzel wire should > I use to maintain the functionality and safety of the copper bar? I'm skeptical of that current number . . . nonetheless, a 4AWG piece of wire would be just fine. If you don't yet have the wire, get a chunk of welding cable from a local welding supplies shop. MUCH more flexible and installer friendly. Be gentle on yourself too . . . don't make the jumper run a tight, straight line between studs. Make it a leisurely hop between mounting locations so that you can exploit that flexibility; i.e. a 6" piece of wire is about right for connecting studs 4" apart. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ------------------------------------------------------------------------------------- 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.