---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 09/07/16: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:00 AM - Re: Ducati R/R deficiencies (David Josephson) 2. 05:20 AM - Attachment limits? (Robert L. Nuckolls, III) 3. 08:19 AM - Re: Attachment limits? (Ken Ryan) 4. 11:43 AM - Re: Attachment limits? (Eric Page) 5. 04:51 PM - Re: Ducatti R/R deficiencies (MMiller) ________________________________ Message 1 _____________________________________ Time: 04:00:16 AM PST US Subject: Re: AeroElectric-List: Ducati R/R deficiencies From: David Josephson On Sep 6, 2016, at 2:04 PM, Bob Nuckolls wrote: > > I took some time to finish an article I started some > years ago explaining my perceptions of thermal management > deficiencies in the Ducatti R/R supplied with Rotax > engines. > > http://tinyurl.com/zvkoh4p Indeed, and thanks. I have disassembled a couple of these and found the same problems. There seem to be two heat-related failure modes: (a) the semiconductors get too hot for the thermal resistance between junction and free air, and (b) the solder joints are poor between the leads of the devices and the pc board, and between the pc board and the connector, leading to localized heating. In two of the cases I have, the solder had melted often enough that the board was charred, and the component leads were not well cleaned so the solder had dirt and oxidation in it. They are no doubt caught up in European lead-free solder requirements too. To be fair these are inexpensive regulators designed for motorcycles where they are often installed in free air -- at the top of the firewall where they are usually found in airplanes is not a particularly cool place for them. Charging a motorcycle battery, plus a headlight, and ignition, is something they can handle well. Rotax can't design/build everything, it would be even more expensive than it is if they did (ever priced a wastegate controller for a 914?) and with proper cooling and low current drain the Ducati r/r is not too bad. Once it starts to fail due to heat however it's downhill from there. The Silent Hektik device seems to be a good replacement although I have not used one -- they will not ship to the US and seem not too interested in the light aviation market anymore. I have designed a more robust version using low Vf diodes and scrs and will probably have some test hours on one by the end of the year. The basic design is OK, I agree with Bob that it just needs better thermal management. ________________________________ Message 2 _____________________________________ Time: 05:20:04 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Attachment limits? Matt, Recently I've received 'bounced' e-mails for postings to the AeroElectric List that cited an exceedance of limits on attachment size. Is this something new? To what size should attachments/ embedded images be limited? Thanks! Bob . . . ________________________________ Message 3 _____________________________________ Time: 08:19:46 AM PST US From: Ken Ryan Subject: Re: AeroElectric-List: Attachment limits? Matt, I have had the same problem, with my attachments being well under the published maximums. On Tue, Sep 6, 2016 at 5:26 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > Matt, > > Recently I've received 'bounced' e-mails for > postings to the AeroElectric List that cited > an exceedance of limits on attachment size. > > Is this something new? To what size should attachments/ > embedded images be limited? > > Thanks! > > > Bob . . . > ________________________________ Message 4 _____________________________________ Time: 11:43:35 AM PST US Subject: Re: AeroElectric-List: Attachment limits? From: Eric Page I'll add one more data point. On a few of these occasions I recall members c ommenting on this problem, but I had received their initial post via the ema il echo system, with the allegedly oversize attachments intact. So, it seem s that in some cases the server is accepting attachments but nonetheless sen ding bounce messages. Eric > On Sep 7, 2016, at 8:15 AM, Ken Ryan wrote: > Matt, I have had the same problem, with my attachments being well under th e published maximums. > > >> On Tue, Sep 6, 2016 at 5:26 PM, Robert L. Nuckolls, III wrote: >> Matt, >> >> Recently I've received 'bounced' e-mails for postings to the AeroElectric List that cited an exceedance of limits on attachment size. >> >> Is this something new? To what size should attachments/embedded images be limited? >> >> Thanks! >> Bob . . . ________________________________ Message 5 _____________________________________ Time: 04:51:04 PM PST US Subject: AeroElectric-List: Re: Ducatti R/R deficiencies From: "MMiller" Bob, You have a few misconceptions about the Rotax regulator. All the power components are screwed to the case, heatsink compound is used. Rotax does not depend on the potting compound for heatsinking the power components. In your photo, item 1 and 2 are SCRs (MCR16N). Item 3 is a MOSFET to drive the fault lamp. The power diodes (button case) are not shown, they would attach between the plate on the left side and the two leads on the lower left side of the PCB. This version is obsolete since late 2009. I posted these links back in July, I guess you missed my post and conclusions. The older pre 2010 regulator Here a is a PDF schematic/assy for this version https://drive.google.com/open?id=0ByPxADyU-DwPdTQ3NWp5LW9iOHc Typical failure mode PDF https://drive.google.com/open?id=0ByPxADyU-DwPTnlXcUVEQTdfcVU Current production since 2010. Here is a PDF schematic/assy for this version https://drive.google.com/open?id=0ByPxADyU-DwPWTBBcGlUeENTcHc Here are some failure PDF photos https://drive.google.com/open?id=0ByPxADyU-DwPYm1rYUVsbUJyQ3M Read this topic online here: http://forums.matronics.com/viewtopic.php?p=460344#460344 ------------------------------------------------------------------------------------- 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.