---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 07/02/20: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:11 AM - Bus Bar Equivalent AWG (Drum) 2. 05:35 AM - Re: Bus Bar Equivalent AWG (Art Zemon) 3. 06:25 AM - Re: Bus Bar Equivalent AWG (Charlie England) 4. 07:07 AM - Re: Bus Bar Equivalent AWG (Art Zemon) 5. 07:39 AM - Re: Bus Bar Equivalent AWG (Robert L. Nuckolls, III) 6. 08:12 AM - Re: Bus Bar Equivalent AWG (Charlie England) 7. 11:28 AM - Hall Effect current sensor and Rotax Alternator (Chris) 8. 11:58 AM - Re: Hall Effect current sensor and Rotax Alternator (Robert L. Nuckolls, III) 9. 06:05 PM - Re: Hall Effect current sensor and Rotax Alternator (Robert L. Nuckolls, III) 10. 06:49 PM - Re: Bus Bar Equivalent AWG (Dick Tasker) 11. 07:24 PM - Re: Hall Effect current sensor and Rotax Alternator (user9253) ________________________________ Message 1 _____________________________________ Time: 05:11:47 AM PST US Subject: AeroElectric-List: Bus Bar Equivalent AWG From: "Drum" Hi - I'm putting together a ground pwr jack for my RV-8. It's easier for me to connect two contactors using bus bar stock instead of AWG 4 wire. Would 0.5"x.025 brass bus bar stock on a 6' run be acceptable? Can't find a table of brass bus bar loading data. Thanks in advance. Warm regards, Drum -------- Drum RV8 - Working on Fuselage/Canopy Southport, CT Read this topic online here: http://forums.matronics.com/viewtopic.php?p=497139#497139 ________________________________ Message 2 _____________________________________ Time: 05:35:24 AM PST US From: Art Zemon Subject: Re: AeroElectric-List: Bus Bar Equivalent AWG Drum, This would be a good time to think about how you are going to use your ground power jack, because that will inform how much current needs to flow through the jack, for how long, and will let you calculate the heat which would be generated. For instance, if you intend to use the jack to power the EFIS while you program it, update the database, etc, then the current is negligible. If you are going to hook up a battery maintainer, again, the current is negligible. If you are going to use it to jump start the airplane with a dead battery then you need to shove a lot of current, which warrants a fat wire or bus bar, but maybe removing the battery and charging it and then reinstalling it would be preferable. Even in this case, you have a lot of current but (hopefully) for a short time so not much heat. -- Art Z. On Thu, Jul 2, 2020 at 7:23 AM Drum wrote: > > Hi - I'm putting together a ground pwr jack for my RV-8. It's easier for > me to connect two contactors using bus bar stock instead of AWG 4 wire. > Would 0.5"x.025 brass bus bar stock on a 6' run be acceptable? Can't find > a table of brass bus bar loading data. > -- https://CheerfulCurmudgeon.com/ *If I am not for myself, who will be for me? If I am only for myself, what am I? If not now, when?* ________________________________ Message 3 _____________________________________ Time: 06:25:43 AM PST US From: Charlie England Subject: Re: AeroElectric-List: Bus Bar Equivalent AWG Art makes a good point. But directly to your question, #4 wire area is 0.03268...sq in. .5 x .025 0.0125 sq in. Brass conductivity is quite a bit worse than copper. So you'd have roughly 1/3 the area, and brass has 28% of the conductivity of copper, if the area was the same. https://www.bluesea.com/resources/108/Electrical_Conductivity_of_Materials#:~:text=Brass%20is%20only%2028%25%20as,7%25%20as%20conductive%20as%20copper!&text=The%20higher%20the%20%25%20IACS%2C%20the,C%20(68%C2%B0F). Offsetting that is the very short distance for a bus bar (minimal total resistance). However, a thickness of 0.065" would give you the same area, and a piece of 3/8" copper tubing (available at your local hardware store), when flattened, would give you a 0.54" x 0.095" bar. Charlie On Thu, Jul 2, 2020 at 7:40 AM Art Zemon wrote: > Drum, > > This would be a good time to think about how you are going to use your > ground power jack, because that will inform how much current needs to flow > through the jack, for how long, and will let you calculate the heat which > would be generated. For instance, if you intend to use the jack to power > the EFIS while you program it, update the database, etc, then the current > is negligible. If you are going to hook up a battery maintainer, again, the > current is negligible. If you are going to use it to jump start the > airplane with a dead battery then you need to shove a lot of current, which > warrants a fat wire or bus bar, but maybe removing the battery and charging > it and then reinstalling it would be preferable. Even in this case, you > have a lot of current but (hopefully) for a short time so not much heat. > > -- Art Z. > > On Thu, Jul 2, 2020 at 7:23 AM Drum wrote: > >> >> Hi - I'm putting together a ground pwr jack for my RV-8. It's easier for >> me to connect two contactors using bus bar stock instead of AWG 4 wire. >> Would 0.5"x.025 brass bus bar stock on a 6' run be acceptable? Can't find >> a table of brass bus bar loading data. >> > > -- > https://CheerfulCurmudgeon.com/ > *If I am not for myself, who will be for me? If I am only for myself, what > am I? If not now, when?* > ________________________________ Message 4 _____________________________________ Time: 07:07:17 AM PST US From: Art Zemon Subject: Re: AeroElectric-List: Bus Bar Equivalent AWG There are a couple more offsetting features of the bus bar. First, it is mounted away from everything else, so that air can circulate freely around it, helping dissipate heat. Second, it is an uninsulated piece of metal. It can get hot without damaging anything, in particular, it can get hot without melting insulation. This is kind of a fun thought experiment but, unless you are going to crank and crank and crank your engine through that ground power jack and a set of jumper cables, I kind of doubt that the choice of a bus bar vs a #4 cable or even vs a piece of AWG 18 wire will make any practical difference. -- Art Z. On Thu, Jul 2, 2020 at 8:42 AM Charlie England wrote: > Art makes a good point. > But directly to your question, #4 wire area is 0.03268...sq in. .5 x .025 > 0.0125 sq in. Brass conductivity is quite a bit worse than copper. So you'd > have roughly 1/3 the area, and brass has 28% of the conductivity of copper, > if the area was the same. > > https://www.bluesea.com/resources/108/Electrical_Conductivity_of_Materials#:~:text=Brass%20is%20only%2028%25%20as,7%25%20as%20conductive%20as%20copper!&text=The%20higher%20the%20%25%20IACS%2C%20the,C%20(68%C2%B0F). > > Offsetting that is the very short distance for a bus bar (minimal total > resistance). > > However, a thickness of 0.065" would give you the same area, and a piece > of 3/8" copper tubing (available at your local hardware store), when > flattened, would give you a 0.54" x 0.095" bar. > > Charlie > > On Thu, Jul 2, 2020 at 7:40 AM Art Zemon wrote: > >> Drum, >> >> This would be a good time to think about how you are going to use your >> ground power jack, because that will inform how much current needs to flow >> through the jack, for how long, and will let you calculate the heat which >> would be generated. For instance, if you intend to use the jack to power >> the EFIS while you program it, update the database, etc, then the current >> is negligible. If you are going to hook up a battery maintainer, again, the >> current is negligible. If you are going to use it to jump start the >> airplane with a dead battery then you need to shove a lot of current, which >> warrants a fat wire or bus bar, but maybe removing the battery and charging >> it and then reinstalling it would be preferable. Even in this case, you >> have a lot of current but (hopefully) for a short time so not much heat. >> >> -- Art Z. >> >> On Thu, Jul 2, 2020 at 7:23 AM Drum wrote: >> >>> >>> Hi - I'm putting together a ground pwr jack for my RV-8. It's easier >>> for me to connect two contactors using bus bar stock instead of AWG 4 >>> wire. Would 0.5"x.025 brass bus bar stock on a 6' run be acceptable? >>> Can't find a table of brass bus bar loading data. >>> >> >> -- >> https://CheerfulCurmudgeon.com/ >> *If I am not for myself, who will be for me? If I am only for myself, >> what am I? If not now, when?* >> > -- https://CheerfulCurmudgeon.com/ *If I am not for myself, who will be for me? If I am only for myself, what am I? If not now, when?* ________________________________ Message 5 _____________________________________ Time: 07:39:08 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Bus Bar Equivalent AWG >However, a thickness of 0.065" would give you the same area, and a >piece of 3/8" copper tubing (available at your local hardware >store), when flattened, would give you a 0.54" x 0.095" bar. Art and Charlie make excellent points. Another possibility is to fabricate a 4AWG welding cable jumper that's a 'bit too long' so that it simply makes a graceful curve between the studs. The copper tube idea has been floated and incorporated in projects here on the list for decades. Copper is the bus bar material of choice and you only need to flatten the ends to facilitate joining at the studs. This technique calls for attention to keeping the two flats planar to each other. My personal choice would be the welding cable jumper. Easy to build, soft and easy to work with. Does not conduct mechanical forces between the studs. I'm recalling an invitation I received from an RV builder in Wichita to visit his project in process on local airport. We had some good discussion about various chapters of his planning. While looking over stuff fire-wall- forward, I noticed that he had grounded battery(-) to the fire-wall sheet with a little chunk of aluminum angle. I brought this to his attention and suggested that the thin stainless was a poor conductor and that forcing it to carry battery recharge and starter cranking currents offer potential for serious ground-loop effects. But more important, the battery mass was getting tied to airframe by non-structural battery terminal by way of a non-ferrous hunk of metal that was almost guaranteed to be his first electrical system failure. I think he was rather fond of his short-n- simple grounding idea . . . he got a bit incensed but it was about time for me to depart anyhow. Never did hear any follow-up on the project. But it's an experience that reminds me to ponder system rigidity between significant chunks of hardware when making hard connection to studs designed for terminating relatively soft wires. Bob . . . ________________________________ Message 6 _____________________________________ Time: 08:12:03 AM PST US Subject: Re: AeroElectric-List: Bus Bar Equivalent AWG From: Charlie England On 7/2/2020 9:37 AM, Robert L. Nuckolls, III wrote: >> However, a thickness of 0.065" would give you the same area, and a >> piece of 3/8" copper tubing (available at your local hardware store), >> when flattened, would give you a 0.54" x 0.095" bar. > > Art and Charlie make excellent points. Another > possibility is to fabricate a 4AWG welding > cable jumper that's a 'bit too long' so that > it simply makes a graceful curve between the > studs. > > The copper tube idea has been floated and > incorporated in projects here on the list > for decades. Copper is the bus bar material > of choice and you only need to flatten the ends > to facilitate joining at the studs. This > technique calls for attention to keeping > the two flats planar to each other. > > My personal choice would be the welding > cable jumper. Easy to build, soft and > easy to work with. Does not conduct > mechanical forces between the studs. > > I'm recalling an invitation I received from > an RV builder in Wichita to visit his project > in process on local airport. We had some > good discussion about various chapters of > his planning. While looking over stuff fire-wall- > forward, I noticed that he had grounded battery(-) > to the fire-wall sheet with a little chunk of aluminum > angle. > > I brought this to his attention and suggested > that the thin stainless was a poor conductor > and that forcing it to carry battery recharge > and starter cranking currents offer potential > for serious ground-loop effects. But more important, > the battery mass was getting tied to airframe > by non-structural battery terminal by way > of a non-ferrous hunk of metal that was almost > guaranteed to be his first electrical system > failure. > > I think he was rather fond of his short-n- > simple grounding idea . . . he got a bit incensed > but it was about time for me to depart anyhow. > Never did hear any follow-up on the project. > But it's an experience that reminds me to > ponder system rigidity between significant > chunks of hardware when making hard connection > to studs designed for terminating relatively > soft wires. > > Bob . . . > I do try to put some variation of an 'S' curve in the flattened copper tubing, when I use that trick. Helps relieve flex stress in one direction, anyway... Charlie -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 7 _____________________________________ Time: 11:28:03 AM PST US From: "Chris" Subject: AeroElectric-List: Hall Effect current sensor and Rotax Alternator I was wondering what locations might be possible for installing a hall effect current sensor on a Z-16 system. Will one or both yellow wires work?? Or, am I limited to the battery lead? Thanks Chris Just Highlander ________________________________ Message 8 _____________________________________ Time: 11:58:18 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Hall Effect current sensor and Rotax Alternator At 01:22 PM 7/2/2020, you wrote: >I was wondering what locations might be possible for installing a >hall effect current sensor on a Z-16 system. Will one or both yellow >wires work?? Or, am I limited to the battery lead? >Thanks >Chris >Just Highlander the yellow wires carry AC current at values related to but different from the DC output of the rectifier regulator. If you're wishing to incorporate the legacy DC hall sensor common to virtually all EFIS systems, the sensor goes in the BAT leads of the rectifier regulator. Bob . . . ________________________________ Message 9 _____________________________________ Time: 06:05:17 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Hall Effect current sensor and Rotax Alternator At 01:22 PM 7/2/2020, you wrote: >I was wondering what locations might be possible for installing a >hall effect current sensor on a Z-16 system. Will one or both yellow >wires work?? Or, am I limited to the battery lead? >Thanks >Chris >Just Highlander See attached Bob . . . ________________________________ Message 10 ____________________________________ Time: 06:49:16 PM PST US Subject: Re: AeroElectric-List: Bus Bar Equivalent AWG From: Dick Tasker Do you really mean 6 ft.? Or is it a typo (6') and should have been 6"? Dick Tasker Drum wrote: > > Hi - I'm putting together a ground pwr jack for my RV-8. It's easier for me to connect two contactors using bus bar stock instead of AWG 4 wire. Would 0.5"x.025 brass bus bar stock on a 6' run be acceptable? Can't find a table of brass bus bar loading data. > > Thanks in advance. > > Warm regards, > > Drum > > -------- > Drum > RV8 - Working on Fuselage/Canopy > Southport, CT > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=497139#497139 > > ________________________________ Message 11 ____________________________________ Time: 07:24:11 PM PST US Subject: AeroElectric-List: Re: Hall Effect current sensor and Rotax Alternator From: "user9253" The yellow wires carry AC current from the Rotax dynamo Run the B & R direct current wires from the Ducati regulator through the hall effect sensor. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=497153#497153 ------------------------------------------------------------------------------------- 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.