---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 02/17/10: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:36 AM - Re: Re: Are home grown temperature probes feasable? (rparigor@suffolk.lib.ny.us) 2. 10:06 AM - Re: Z-12 SD-20 wire size / fusible link size (Robert L. Nuckolls, III) 3. 03:20 PM - Re: Basic Electricity....Grrrrr......... (XeVision) 4. 05:23 PM - Re: Are home grown temperature probes feasable? (rampil) 5. 06:03 PM - S701 Contactor Failure Analysis (Robert L. Nuckolls, III) 6. 06:20 PM - Re: S701 Contactor Failure Analysis (Robert L. Nuckolls, III) 7. 06:48 PM - Re: S701 Contactor Failure Analysis (Ron Quillin) 8. 07:13 PM - Re: S701 Contactor Failure Analysis (Bret Smith) 9. 08:13 PM - Re: S701 Contactor Failure Analysis (Richard E. Tasker) 10. 08:22 PM - Re: S701 Contactor Failure Analysis (Bill Watson) 11. 09:33 PM - Re: S701 Contactor Failure Analysis (Robert L. Nuckolls, III) 12. 09:36 PM - Re: S701 Contactor Failure Analysis (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 12:36:10 AM PST US Subject: Re: AeroElectric-List: Re: Are home grown temperature probes feasable? From: rparigor@suffolk.lib.ny.us Hi Ira Thx for the info on your 15 probes. Curious, you mention you have 4 CHT ring probes that I think are the type that get sandwiched between spark plug and cylinder head. Why did you go that route as compared to purchasing two extra CHT probes from Rotax which would allow reading all 4 cylinders? Perhaps it gives you a more desirable reading? Or?? Thx. Ron Parigoris ________________________________ Message 2 _____________________________________ Time: 10:06:30 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-12 SD-20 wire size / fusible link size At 12:44 AM 2/17/2010, you wrote: > >Bob, > >(Rev 12A) Z-12 suggests using a 10 gauge wire for the B-lead from >the SD-20 with a 16 gauge fusible link. I believe you recommend >sizing fusible links with wire that is 4 sizes smaller than the wire >being protected. I'm guessing the B-lead wire size was changed >during a cut-&-paste from 12 gauge to 10 gauge without re-sizing the >fusible link? Do you recommend 10 gauge wire for an SD-20 B-lead and >if so do you recommend 14 gauge wire for a fusible link if a fusible >link is used to protect the B-lead? 16AWG would be fine . . . so would 14AWG . . . it just needs to serve the function of "electrically weak link" while not overheating beyond that which the insulation will stand . . . 16AWG isn't even close to getting too hot at 20A. See: http://aeroelectric.com/Pictures/Wire/22AWG_20A.pdf I'm working on tooling to build a base for the minature ANL style current limiters. We'll be offering these "robust fuses" on the website in the not too distant future. That "4AWG downsize" rule is a minimum step size, it COULD be 6 or even 8AWG smaller in some cases. For a 20A alternator, 12AWG b-lead with a 16AWG fusible link would be centered on contemporary design goals. Bob . . . ________________________________ Message 3 _____________________________________ Time: 03:20:53 PM PST US Subject: AeroElectric-List: Re: Basic Electricity....Grrrrr......... From: "XeVision" We encounter an even more basic issue on occasion regarding 12 or 24Volts availability at the ballast. Once in a while, we get the call "I have 12 volts at the ballast input connector but the light does not come on when I hook power to it". My response is typically, try measuring the voltage at that location with a load on it. Either our system, a light bulb (incandescent) or other load. Do you still have about 12V or 24V with the load or does the voltage plummet as soon as a load is applied. If so, look for corroded connections in the wiring, a bad switch, a bad ground, etc. Sometimes they are using the airframe for ground (not our preference) and sometimes the airframe at that location is not well grounded back to the neg bus/ neg bat terminal. People building airplanes, if they do any of the electrical work, should learn some basics of how electrical circuits work. When they don't understand these basics they automatically blame the non operational component(s). -------- LED still has a long way to go to compete with HID as a landing light. This is true in terms of total lumens and reach (distance). Read this topic online here: http://forums.matronics.com/viewtopic.php?p=286865#286865 ________________________________ Message 4 _____________________________________ Time: 05:23:43 PM PST US Subject: AeroElectric-List: Re: Are home grown temperature probes feasable? From: "rampil" nope, the reason was BMA compatibility -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=286870#286870 ________________________________ Message 5 _____________________________________ Time: 06:03:45 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: S701 Contactor Failure Analysis Last year, Marty Emrath told us about the failure of a new contactor he had purchased from B&C. B&C replaced the contactor but Marty was justifiably curious as to root cause of the failure. I offered to document a tear-down analysis and Marty sent me the carcass. I was looking for something fun to do this afternoon so I took the dead puppy apart. The pictures at . . . http://www.aeroelectric.com/Pictures/Contactors/S701_Failure_Teardown/ Are pretty much self explanatory. One thing is for certain. This product is much more sophisticated than its ancestors that first took to the air in a C-140. The last picture tells the tale . . . http://www.aeroelectric.com/Pictures/Contactors/S701_Failure_Teardown/TearDown_10.jpg Seems the assembler wasn't really awake yet when this device went across their work station. One coil wire was poorly soldered to its terminal . . . the other had no solder at all. Thanks for sharing your experience with us Martin! Bob . . . ________________________________ Message 6 _____________________________________ Time: 06:20:02 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: S701 Contactor Failure Analysis > >The last picture tells the tale . . . > >http://www.aeroelectric.com/Pictures/Contactors/S701_Failure_Teardown/TearDown_10.jpg > >Seems the assembler wasn't really awake yet when this >device went across their work station. One coil wire >was poorly soldered to its terminal . . . the other had >no solder at all. Already had a comment on the analysis . . . someone noted that the terminals around which the coil wires are wrapped are square and may indeed have sharp corners. He reminded me of an arcane point-to-point wiring process for complex digital circuits called "wire wrap". This process used special wire, tools, sharp edged square terminal posts and no solder. The tools were designed to tightly wrap the wire around the post with enough turns, and stretching force to create multiple gas-tight joints on the corners at each connection. As I recall this technology called for about 6 tightly spaced turns around the post (24+ points of contact). Since this coil-form is plastic . . . and soldering these joints would call for considerable heat and time, it may well be that the original design calls for no solder at all. In this case, the assembler of the failed item was perhaps not in possession of the right tool. The turns about both posts are not those produced by a "wire wrap" tool. The curious thing is that there is SOME solder on one of the terminals . . . perhaps didn't pass a continuity test and the solder dab "fixed it" only to have the other joint fail later. Guess we'll have to tear down another contactor to see. I don't think I have one in the shop. I'll go buy one. Bob . . . ________________________________ Message 7 _____________________________________ Time: 06:48:32 PM PST US From: Ron Quillin Subject: Re: AeroElectric-List: S701 Contactor Failure Analysis You have a good recollection. I just did some wire-wrap late last year. However, the wire used has Kynar or other insulation that is removed to expose a bare, generally tin coated, conductor. The wire used to wind the coil, from your pictures, appears to be 'magnet' wire which has an insulating coating. The wire-wrap process, as I have always seen it implemented, is not designed for this type of insulated wire and is not expected to breech the insulation to form a contact. I believe your original diagnosis of no solder was spot-on. Ron Q. At 18:18 2/17/2010, you wrote: >He reminded me of an arcane point-to-point wiring process > for complex digital circuits called "wire wrap". This > process used special wire, tools, sharp edged square terminal > posts and no solder. The tools were designed to tightly > wrap the wire around the post with enough turns, and > stretching force to create multiple gas-tight joints > on the corners at each connection. > > As I recall this technology called for about 6 tightly > spaced turns around the post (24+ points of contact). > Since this coil-form is plastic . . . and soldering these > joints would call for considerable heat and time, > it may well be that the original design calls for > no solder at all. ________________________________ Message 8 _____________________________________ Time: 07:13:14 PM PST US From: "Bret Smith" Subject: RE: AeroElectric-List: S701 Contactor Failure Analysis Thank you Bob, It is always interesting to learn more about the art of aircraft electronics. Bret Smith RV-9A N16BL Blue Ridge, GA www.FlightInnovations.com -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, February 17, 2010 9:18 PM Subject: Re: AeroElectric-List: S701 Contactor Failure Analysis > >The last picture tells the tale . . . > >http://www.aeroelectric.com/Pictures/Contactors/S701_Failure_Teardown/TearD own_10.jpg > >Seems the assembler wasn't really awake yet when this >device went across their work station. One coil wire >was poorly soldered to its terminal . . . the other had >no solder at all. Already had a comment on the analysis . . . someone noted that the terminals around which the coil wires are wrapped are square and may indeed have sharp corners. He reminded me of an arcane point-to-point wiring process for complex digital circuits called "wire wrap". This process used special wire, tools, sharp edged square terminal posts and no solder. The tools were designed to tightly wrap the wire around the post with enough turns, and stretching force to create multiple gas-tight joints on the corners at each connection. As I recall this technology called for about 6 tightly spaced turns around the post (24+ points of contact). Since this coil-form is plastic . . . and soldering these joints would call for considerable heat and time, it may well be that the original design calls for no solder at all. In this case, the assembler of the failed item was perhaps not in possession of the right tool. The turns about both posts are not those produced by a "wire wrap" tool. The curious thing is that there is SOME solder on one of the terminals . . . perhaps didn't pass a continuity test and the solder dab "fixed it" only to have the other joint fail later. Guess we'll have to tear down another contactor to see. I don't think I have one in the shop. I'll go buy one. Bob . . . ________________________________ Message 9 _____________________________________ Time: 08:13:14 PM PST US From: "Richard E. Tasker" Subject: Re: AeroElectric-List: S701 Contactor Failure Analysis Your recollection is generally true and the same as the wire I have used for all the wire wrapping I have done. However, once upon a time there was wire sold for wrapping that did not require stripping. Unfortunately, I don't remember who sold it nor do I have any. Further, I seem to recall that it was not too successful as it eventually tended to short anywhere it overlapped under tension. The wire on the teardown certainly looks like common magnet wire. And in any case, three or four turns would certainly not be sufficient to make long term reliable contact in something like this which is likely to be exposed to rather harsh environmental conditions. I agree with Bob that they just forgot to solder the wires - the operator probably got interrupted during assembly. Dick Tasker Ron Quillin wrote: > You have a good recollection. > > I just did some wire-wrap late last year. > However, the wire used has Kynar or other insulation that is removed > to expose a bare, generally tin coated, conductor. > > The wire used to wind the coil, from your pictures, appears to be > 'magnet' wire which has an insulating coating. The wire-wrap process, > as I have always seen it implemented, is not designed for this type of > insulated wire and is not expected to breech the insulation to form a > contact. > > I believe your original diagnosis of no solder was spot-on. > > Ron Q. > > At 18:18 2/17/2010, you wrote: >> He reminded me of an arcane point-to-point wiring process >> for complex digital circuits called "wire wrap". This >> process used special wire, tools, sharp edged square terminal >> posts and no solder. The tools were designed to tightly >> wrap the wire around the post with enough turns, and >> stretching force to create multiple gas-tight joints >> on the corners at each connection. >> >> As I recall this technology called for about 6 tightly >> spaced turns around the post (24+ points of contact). >> Since this coil-form is plastic . . . and soldering these >> joints would call for considerable heat and time, >> it may well be that the original design calls for >> no solder at all. > * > > > * -- Please Note: No trees were destroyed in the sending of this message. We do concede, however, that a significant number of electrons may have been temporarily inconvenienced. -- ________________________________ Message 10 ____________________________________ Time: 08:22:17 PM PST US From: "Bill Watson" Subject: Re: AeroElectric-List: S701 Contactor Failure Analysis I'm feeling old... My only hands-on experimental circuit making was pre-dig ital. =C2- Over the years I'd pickup electronics mags and see references to "wire wrapped" terminals and never had a clue what it referred to. =C2 -Now I get it... Thanks. Bill -- Sent from my Palm Pre Ron Quillin wrote: You have a good recollection. I just did some wire-wrap late last year. However, the wire used has Kynar or other insulation that is removed to expose a bare, generally tin coated, conductor. The wire used to wind the coil, from your pictures, appears to be 'magnet' wire which has an insulating coating.=C2- The wire-wrap process, as I have always seen it implemented, is not designed for this type of insulated wire and is not expected to breech the insulation to form a contact. I believe your original diagnosis of no solder was spot-on. Ron Q. At 18:18 2/17/2010, you wrote: He reminded me of an arcane point-to-point wiring process =C2- for complex digital circuits called "wire wrap". This =C2- process used special wire, tools, sharp edged square terminal =C2- posts and no solder. The tools were designed to tightly =C2- wrap the wire around the post with enough turns, and =C2- stretching force to create multiple gas-tight joints =C2- on the corners at each connection. =C2- As I recall this technology called for about 6 tightly =C2- spaced turns around the post (24+ points of contact). =C2- Since this coil-form is plastic . . . and soldering these =C2- joints would call for considerable heat and time, =C2- it may well be that the original design calls for =C2- no solder at all. ________________________________ Message 11 ____________________________________ Time: 09:33:03 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: S701 Contactor Failure Analysis At 10:22 PM 2/17/2010, you wrote: >I'm feeling old... My only hands-on experimental >circuit making was pre-digital. Over the >years I'd pickup electronics mags and see >references to "wire wrapped" terminals and never >had a clue what it referred to. Now I get it... Thanks. > >Bill see: http://en.wikipedia.org/wiki/Wire_wrap This is the modern incarnation used on complex backplanes where gazillion-layer boards are impractical. The no-strip version is from way-back-when and it didn't hang around long. Bob . . . ________________________________ Message 12 ____________________________________ Time: 09:36:26 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: S701 Contactor Failure Analysis >The wire on the teardown certainly looks like common magnet >wire. And in any case, three or four turns would certainly not be >sufficient to make long term reliable contact in something like this >which is likely to be exposed to rather harsh environmental >conditions. I agree with Bob that they just forgot to solder the >wires - the operator probably got interrupted during assembly. Just for grins, I took a chunk of the wire off the failed coil and subjected it to a puddle of molten solder. The insulation was indeed a "solder-eze" type . . . you can solder through it without pre- stripping. The plastic used on the bobbin did melt at soldering iron temperatures but not quickly. So it seems a rational deduction that the failed joints were intended to be soldered. The right temperature and flux combination would have produced a reliable joint with minimal effect on the bobbin. I guess I won't go buy one to take apart . . . perhaps we'll get another carcass to inspect for other reasons one day. 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.