---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 08/09/14: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:18 AM - Shunt Questions (Valovich, Paul) 2. 09:45 AM - Re: Shunt Questions (Daniel Hooper) 3. 10:11 AM - Re: Shunt Questions (Jeff Luckey) 4. 12:33 PM - Re: Shunt Questions (Robert L. Nuckolls, III) 5. 04:08 PM - Re: Shunt Questions (Vern Little) ________________________________ Message 1 _____________________________________ Time: 09:18:02 AM PST US From: "Valovich, Paul" Subject: AeroElectric-List: Shunt Questions RV-8A, 420 total hours. Electrical design based on Z13/8 architecture. AFS 4500 EFIS taking ammeter current readings from 50 MV / 60 amp shunt. Ammeter reading suddenly became very intermittent - mostly inop. Replaced w ires, D-sub pins, connectors. Extensive troubleshooting with Advanced Fligh t Systems has led to questions about whether shunt is working properly. How does one troubleshoot a shunt? No moving parts; no visible damage; All other electrical systems operating normally. Paul Valovich Ridgecrest, CA N192NM ________________________________ Message 2 _____________________________________ Time: 09:45:14 AM PST US Subject: Re: AeroElectric-List: Shunt Questions From: Daniel Hooper Could you hook it up temporarily to a good quality volt meter (at the remote end)? That could help eliminate some things. Daniel Hooper > On Aug 9, 2014, at 11:16 AM, "Valovich, Paul" wrot e: > > RV-8A, 420 total hours. Electrical design based on Z13/8 architecture. AFS 4500 EFIS taking ammeter current readings from 50 MV / 60 amp shunt. > > Ammeter reading suddenly became very intermittent =93 mostly inop. R eplaced wires, D-sub pins, connectors. Extensive troubleshooting with Advanc ed Flight Systems has led to questions about whether shunt is working proper ly. > > How does one troubleshoot a shunt? No moving parts; no visible damage; All other electrical systems operating normally. > Paul Valovich > Ridgecrest, CA > N192NM > > > 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > ________________________________ Message 3 _____________________________________ Time: 10:11:38 AM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: Shunt Questions =0AHow does one troubleshoot a shunt? =0A=0A=0AGreat question - shunts are about as "solid-state" as they come.=0A=0ABased on you conversations w/ Adv anced, we assume that it's not =0Asomething in their system.=C2- Have you tried swapping-in a known-good =0Ashunt?=0A=0AAs you may already know, a s hunt is really just a highly-calibrated, very low-resistance resistor.=C2 - On many shunts the main element is soldered between the connection post s.=C2- I'm wondering if there is some kind of mechanical problem in there somewhere.=C2- I assume there are no visible cracks or other damage.=0A =0A=0ATo test a shunt you could:=0A=0A1.=C2- hook-up a test circuit (on t he bench) with a battery and some small load - maybe a couple of automotive brake lights (or equivalent).=C2- You want a load of around 5 amps for t his test.=0A=0A2. Hook-up a DVM to the shunt on the mili-volt scale.=C2- Your shunt you should be reading just about 1 mV per Amp of current in the circuit. (technically that's 5/6 mV per Amp, but that's really splitting ha irs)=0A=0A3. While the circuit is on, agitate the shunt: bang in on the ben ch top or hit it w/ a plastic mallet and see if the reading remains steady. =C2- Perhaps some part of the shunt is damaged/cracked and it is having i ntermittent connection problems. (you will want to have good solid connecti ons on the shunt terminals for this test - alligator clips probably won't d o it)=0A=0A4. It would be fun to test w/ high load, something like 40-50 am ps, but I can't think of an easy way to create a load like that - maybe oth er Listers have some ideas...=0A=0A=0AGood Luck & keep us posted,=0A=0A-Jef f=0A=0A=0A=0A=0A=0A=0AOn Saturday, August 9, 2014 9:28 AM, "Valovich, Paul" wrote:=0A =0A=0A=0A =0ARV-8A, 420 total hours. Ele ctrical design based on Z13/8 architecture. AFS 4500 EFIS taking ammeter cu rrent readings from 50 MV / 60 amp shunt.=0A=C2-=0AAmmeter reading sudden ly became very intermittent =93 mostly inop. Replaced wires, D-sub pi ns, connectors. Extensive troubleshooting with Advanced Flight Systems has led to questions about whether shunt is working properly.=0A=C2-=0AHow do es one troubleshoot a shunt? No moving parts; no visible damage; All other electrical systems operating normally. =0APaul Valovich=0ARidgecrest, CA=0A ====================== ________________________________ Message 4 _____________________________________ Time: 12:33:20 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Shunt Questions At 12:10 PM 8/9/2014, you wrote: >How does one troubleshoot a shunt? > >Great question - shunts are about as "solid-state" as they come. > >Based on you conversations w/ Advanced, we assume that it's not >something in their system. Have you tried swapping-in a known-good shunt? > >As you may already know, a shunt is really just a highly-calibrated, >very low-resistance resistor. On many shunts the main element is >soldered between the connection posts. I'm wondering if there is >some kind of mechanical problem in there somewhere. I assume there >are no visible cracks or other damage. The only shunts I've seen 'fail' were destroyed by gross over-current. If the thing is not discolored and the screws are tight, it's good. Bob . . . ________________________________ Message 5 _____________________________________ Time: 04:08:56 PM PST US From: Vern Little Subject: Re: AeroElectric-List: Shunt Questions I destroyed a Dynon supplied shunt because the plastic base melted. It was located FWF. The fix was to fabricate a new base out of Bakelite. I remember the day when they were all made that way... Vern =================================================== Sent from my iThing. It is responsible for all gramma and typo terrors. > On Aug 9, 2014, at 12:32 PM, "Robert L. Nuckolls, III" wrote: > > > At 12:10 PM 8/9/2014, you wrote: > >> How does one troubleshoot a shunt? >> >> Great question - shunts are about as "solid-state" as they come. >> >> Based on you conversations w/ Advanced, we assume that it's not something in their system. Have you tried swapping-in a known-good shunt? >> >> As you may already know, a shunt is really just a highly-calibrated, very low-resistance resistor. On many shunts the main element is soldered between the connection posts. I'm wondering if there is some kind of mechanical problem in there somewhere. I assume there are no visible cracks or other damage. > > The only shunts I've seen 'fail' were > destroyed by gross over-current. If the thing > is not discolored and the screws are tight, > it's good. > > > > 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.