---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 08/03/16: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:52 AM - Re: Aux power to learn avionics (rampil) 2. 06:53 AM - Re: Using the "Poor man's 4-wire milliohmmeter" (user9253) 3. 07:58 AM - Re: Re: Using the "Poor man's 4-wire milliohmmeter" (Kent or Jackie Ashton) 4. 10:02 AM - Re: Using the "Poor man's 4-wire milliohmmeter" (user9253) 5. 01:17 PM - Re: Re: Using the "Poor man's 4-wire milliohmmeter" (Robert L. Nuckolls, III) 6. 02:11 PM - Re: Using the "Poor man's 4-wire milliohmmeter" (Robert L. Nuckolls, III) 7. 02:45 PM - Re: Using the "Poor man's 4-wire milliohmmeter" (Robert L. Nuckolls, III) 8. 03:21 PM - ADS-B Antenna (Roger) 9. 03:55 PM - Re: ADS-B Antenna (user9253) 10. 04:33 PM - Re: Re: Using the "Poor man's 4-wire milliohmmeter" (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:52:46 AM PST US Subject: AeroElectric-List: Re: Aux power to learn avionics From: "rampil" BTW, Batteries are made to be drained! No harm, no foul! You just need to recharge your lead acid battery when you are done studying. Discharging your battery to the point where your avionics quits (probably about 10 volts(here I am guessing that the avionics is universal 12-24 compatible)) will not harm the battery. Some avionics (with poor design) may complain more. And yes, The voltage was probably declining due to current draw in excess of charger supply -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=459155#459155 ________________________________ Message 2 _____________________________________ Time: 06:53:00 AM PST US Subject: AeroElectric-List: Re: Using the "Poor man's 4-wire milliohmmeter" From: "user9253" Another option: Disconnect the aircraft battery negative terminal. Assuming that the master contactor has a single coil terminal and the starter contactor has two coil terminals, unbolt the master contactor from the firewall and isolate it from ground. Energize both contactors with an aux battery. The aux battery positive should be connected directly to the battery contactor positive stud, not to the nuts. Now the resistance of the starter circuit can be measured at any location between the aircraft battery positive post and the disconnected negative battery-cable end. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=459156#459156 ________________________________ Message 3 _____________________________________ Time: 07:58:00 AM PST US Subject: Re: AeroElectric-List: Re: Using the "Poor man's 4-wire milliohmmeter" From: Kent or Jackie Ashton > On Aug 3, 2016, at 9:51 AM, user9253 wrote: > > > Another option: Disconnect the aircraft battery negative terminal. Assuming that the master contactor has a single coil terminal and the starter contactor has two coil terminals, unbolt the master contactor from the firewall and isolate it from ground. Energize both contactors with an aux battery. The aux battery positive should be connected directly to the battery contactor positive stud, not to the nuts. > Now the resistance of the starter circuit can be measured at any location between the aircraft battery positive post and the disconnected negative battery-cable end. Yes, I can see that. This is a Long-EZ with battery & master solenoid in the nose on fiberglass structure and a starter solenoid on the aft metal firewall. I dont see the need to dismount the solenoids but your suggestion would allow me to test the whole circuit from the battery area. I dont know the internal resistance of my Skytec starter. I suppose I can measure it separately. However, I think today Ill just measure the resistance of some assembled joints on various large cables I have in the shop and compare that to some of the roughly soldered joints in the airplane cables. If that doesnt reveal a bad joint, Ill try something else. Thanks for the help. -Kent ________________________________ Message 4 _____________________________________ Time: 10:02:16 AM PST US Subject: AeroElectric-List: Re: Using the "Poor man's 4-wire milliohmmeter" From: "user9253" The reason that I suggested isolating the battery contactor from ground is because its coil is connected in parallel with the starter motor when the starter contactor is energized. Your fiberglass airplane might be wired differently than metal aircraft. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=459167#459167 ________________________________ Message 5 _____________________________________ Time: 01:17:05 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Using the "Poor man's 4-wire milliohmmeter" > Yes, I can see that. This is a Long-EZ > with battery & master solenoid in the nose on > fiberglass structure and a starter solenoid on > the aft metal firewall. I don=99t see the need > to dismount the solenoids but your suggestion > would allow me to test the whole circuit from the battery area. What gage wire is used for battery and ground leads that run the length of the aircraft? Bob . . . ________________________________ Message 6 _____________________________________ Time: 02:11:58 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Using the "Poor man's 4-wire milliohmmeter" At 02:01 PM 8/2/2016, you wrote: >Jackie Ashton > >Hi Bob, > > I made one of these to troubleshoot a > sluggish starter on a Long-EZ from your > excellent discussion > here > http://www.aeroelectric.com/articles/grnding.pdf > I suspect I have some bad solder joints in > connectors on copper-clad aluminum cables and > thinking of the best way to test for excessive resistance. I am thinking: > > I could test each connector joint by > isolating the cable & connector and probing > between the clean bare cable and the connector, or > > Alternatively, perhaps I could test the > entire cable run and the solenoids by > disconnecting the cable it at the battery and > the starter, activating the master and starter > solenoids with a portable battery and probing > between the battery-end and the starter-end. > > Or could I disconnect the starter cable > at the starter, active the master and starter > solenoids with the usual switchology and probe > between the battery post and the starter-end of > the cables. Does connection to the battery affect the test? > > What=99s your preferred strategy here? Thanks. > >-Kent > Bob . . . ________________________________ Message 7 _____________________________________ Time: 02:45:12 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Using the "Poor man's 4-wire milliohmmeter" At 02:01 PM 8/2/2016, you wrote: > > >Hi Bob, > > I made one of these to troubleshoot a sluggish starter on a > Long-EZ from your excellent discussion > here http://www.aeroelectric.com/articles/grnding.pdf I suspect > I have some bad solder joints in connectors on copper-clad aluminum > cables and thinking of the best way to test for excessive > resistance. I am thinking: Hmmmm . . . that tool is useful for evaluating the quality of any one joint and it assumes that you have some notion of the resistance value representing a quality joint . . . > I could test each connector joint by isolating the cable & > connector and probing between the clean bare cable and the connector, or > > Alternatively, perhaps I could test the entire cable run > and the solenoids by disconnecting the cable it at the battery and > the starter, activating the master and starter solenoids with a > portable battery and probing between the battery-end and the starter-end. > > Or could I disconnect the starter cable at the starter, > active the master and starter solenoids with the usual switchology > and probe between the battery post and the starter-end of the > cables. Does connection to the battery affect the test? One of my favorite tools for chasing this dragon (and similar issues) is this modified battery tester from Harbor Freight. Emacs! In this instance, the device is also used as a high current load for my test bench . . . you may not want to cut the leads so short. In any case, this mod allows you to bolt the load into the system with good mechanical/electrical integrity. When you strip the wires to attach fat-wire lugs, be sure to find ANOTHER wire buried in with the strands of the fat-wire. This is the SENSE wire for the voltmeter. To troubleshoot integrity of your cranking circuit, connect (-) lead to crankcase. (+) lead to the BATTERY side of your starter contactor. With the master switch ON, you should read battery voltage. Then crank the puppy up to some handy value . . . say 150 amps. The voltage should NOT be less than 9v. If less, the next handy-tool for one-man diagnostics is a very long set of leads for your multimeter that will let you clip to the (-) side of the battery and then take successive measurements of VOLTAGE at battery(+), battery side of battery contactor and crankcase while generating the same, test load as before. These readings will let you evaluate ground and supply segments of the cranking circuit INDEPENDENT of starter controls. The next test may be a two person test . . . disconnect the (+) lead from your starter motor and connect (+) lead of your HarborFreight tool to the starter motor power lead. While someone presses the start switch in the cockpit, repeat the votlage measurement under the 150A load. You need to do this with some dispatch . . . starter contactors should not be energized for more than 10 second or so without a cooling period of a minute or so. Once you have the numbers observed in these experiments, the combination of conditions that add up to your perceived performance issue will be easily deduced. Bob . . . ________________________________ Message 8 _____________________________________ Time: 03:21:59 PM PST US From: Roger Subject: AeroElectric-List: ADS-B Antenna I am in the process of gathering information for the installation of an ADS -B in my all wood airplane. The Transponder that I am considering uses 2 a ntennas for the UAT 978 MHz portion. I am considering using the small rod antenna which is similar to that used for the transponder. Since it is a d ifferent frequency than the xponder I will purchase the one specifically fo r the UAT. I am assuming that it is OK to mount this antenna inside the wo od fuselage. Is this correct? Also I believe that it will need a ground p lane. Is there a recommended configuration for the ground of this antenna? Would the 2 antennas be set up identically? Roger Sent from Mail for Windows 10 ________________________________ Message 9 _____________________________________ Time: 03:55:26 PM PST US Subject: AeroElectric-List: Re: ADS-B Antenna From: "user9253" There was a recent thread about transponder antennas that might help: http://forums.matronics.com/viewtopic.php?t=16762861&sid=0fdc43cf144daf15623736558e046890 I have read that a transponder antenna may also be used for 978 MHZ. At the iFly booth in OSH, I was impressed by the pinBuddy dual band ADS-B receiver that is a fraction of the size and uses a fraction of the power of the Stratux. http://www.uavionix.com/ -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=459185#459185 ________________________________ Message 10 ____________________________________ Time: 04:33:55 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Using the "Poor man's 4-wire milliohmmeter" At 04:11 PM 8/2/2016, you wrote: > >Disconnect the starter and replace it with a high wattage >load. Connect the negative side of the high wattage load to the >starter housing. Turn on the battery contactor and the starter >contactor. Connect the RED voltmeter lead to the POSITIVE battery >post. Then using the black voltmeter probe, measure the voltage >drop at various points between the positive battery post and the >high wattage load. Harbor Freight sells a 100 amp battery load tester for $22. >http://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html Agreed. This is a useful tool for chasing this dragon (and similar issues). I've modified this one for improved electrical/mechanical integrity. Emacs! In this instance, the device is also used as a high current load for my test bench . . . you may not want to cut the leads so short. When you strip the wires to attach fat-wire lugs, be sure to find ANOTHER wire buried in with the strands of the fat-wire. This is the SENSE wire for the voltmeter. To troubleshoot integrity of your cranking circuit, connect (-) lead to crankcase. (+) lead to the BATTERY side of your starter contactor. With the master switch ON, you should read battery voltage. Then crank the puppy up to some handy value . . . say 150 amps. The voltage should NOT be less than 9v. If less, the next handy-tool for one-man diagnostics is a very long set of leads for your multimeter that will let you clip to the (-) side of the battery and then take successive measurements of VOLTAGE at battery(+), battery side of battery contactor and crankcase while generating the same, test load as before. These readings will let you evaluate ground and supply segments of the cranking circuit INDEPENDENT of starter controls. The next test may be a two person test . . . disconnect the (+) lead from your starter motor and connect (+) lead of your HarborFreight tool to the starter motor power lead. While someone presses the start switch in the cockpit, repeat the votlage measurement under the 150A load. You need to do this with some dispatch . . . starter contactors should not be energized for more than 10 second or so without a cooling period of a minute or so. Once you have the numbers observed in these experiments, the combination of conditions that add up to your perceived performance issue will be easily deduced. 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.