---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 06/18/20: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:37 AM - Re: Re: Z101 with Rotax 915iS (Matthew S. Whiting) 2. 05:19 AM - Re: Z-11 ground avionics bus question (johnbright) 3. 06:32 AM - Re: Re: Z101 with Rotax 915iS (Ken Ryan) 4. 07:40 AM - Re: Re: Surplus Wire (Robert L. Nuckolls, III) 5. 08:04 AM - Re: Surplus Wire (BMC_Dave) 6. 06:27 PM - Altitude encoder output voltages (Finn Lassen) ________________________________ Message 1 _____________________________________ Time: 04:37:58 AM PST US From: "Matthew S. Whiting" Subject: Re: AeroElectric-List: Re: Z101 with Rotax 915iS What emergency power switch? I see no such reference in the 915iS installation manual. I looked at HIC A and B and X3 and I see no such switch terminals. X3-1 allows external power to be used in the event that both generator A and B fail together, but I see no emergency power switch. > On Jun 18, 2020, at 3:36 AM, Ken Ryan wrote: > > > If Gen A fails, the ECU will disconnect Gen B from the charging system (battery) and connect it to essential engine loads. Rotax does not want you to do it, but if you then close the Emergency Power switch, Gen B will also be re-connected to the charging system. In this condition, it would be possible to load the generator to the point where voltage drops to a level where the essential engine equipment fails. Because Rotax does not publish how much current the engine requires, it is difficult to determine what is safely available for running non-engine equipment. ________________________________ Message 2 _____________________________________ Time: 05:19:05 AM PST US Subject: AeroElectric-List: Re: Z-11 ground avionics bus question From: "johnbright" n13en71(at)gmail.com wrote: > I hope the answer to this question is not too obvious; > > > On Z-11 (and others), the connection between the instrument panel ground bus and the avionics ground bus is designated 5X20AWG. What exactly does that mean? > Do I take up 5 tabs on my ground buses with 20 ga wires?Thanks, > Ben > Glastar Hi Ben, Have you seen Figure 18-17 in the Aeroelectric Connection Book? (and the accompanying text) Note that in Figure 18-17, "(Instrument) Panel Ground Bus" means forest of tabs aft side of firewall in the case of a tractor and in the cabin in the case of a pusher. The term "Panel Ground Bus" has been changed to "Firewall Ground Bus") on newer dwgs like Z101. -------- John Bright, RV-6A, at FWF, O-360 Z-101 single batt dual alt SDS EM-5-F. john_s_bright@yahoo.com, Newport News, Va https://drive.google.com/drive/folders/1u6GeZo6pmBWsKykLNVQMvu4o1VEVyP4K Read this topic online here: http://forums.matronics.com/viewtopic.php?p=496907#496907 ________________________________ Message 3 _____________________________________ Time: 06:32:19 AM PST US From: Ken Ryan Subject: Re: AeroElectric-List: Re: Z101 with Rotax 915iS In the latest Installation Manual it is referred to as "Battery Backup Switch." On Thu, Jun 18, 2020 at 3:41 AM Matthew S. Whiting wrote: > m.whiting@frontier.com> > > > What emergency power switch? I see no such reference in the 915iS > installation manual. I looked at HIC A and B and X3 and I see no such > switch terminals. X3-1 allows external power to be used in the event tha t > both generator A and B fail together, but I see no emergency power switch .. > > > > On Jun 18, 2020, at 3:36 AM, Ken Ryan wrote: > > > > =EF=BB > > If Gen A fails, the ECU will disconnect Gen B from the charging system > (battery) and connect it to essential engine loads. Rotax does not want y ou > to do it, but if you then close the Emergency Power switch, Gen B will al so > be re-connected to the charging system. In this condition, it would be > possible to load the generator to the point where voltage drops to a leve l > where the essential engine equipment fails. Because Rotax does not publis h > how much current the engine requires, it is difficult to determine what i s > safely available for running non-engine equipment. > > =========== =========== =========== =========== =========== > > ________________________________ Message 4 _____________________________________ Time: 07:40:36 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Surplus Wire At 09:55 PM 6/17/2020, you wrote: > >Looking at the BMS13-48 spec the flat shield is tin coated copper, >0.0015" +-.0004 thk and 0.020" wide. I counted 16 strands in the >braid I disassembled. > >So 0.02"x.0011"x16 is 0.000352 sqin area, which is between 13-14ga >(13.6, apparently). So that's what, 20ish Amps conservatively? > >So the 5x 24ga conductors, slightly de-rated to 10A, seems the >shield would be more than up to it. Not sure about your numbers. 14AWG solid wire is .065" diam. 3.14 x (.065/2)^2 = 0.0033 sq" so I think your shield cross section compared to 14 AWG is off by a factor of 10? 24AWG is .02" diameter for a cross section of 3.14 x (.02/2)^2 = 0.000314 sq" x 5 strands is a total of 0.00157 sq". Working backwards I get a diameter of 0.0447 which is pretty close to 17AWG wire for equivalent resistance of the bundled strands. I get 0.00048 sq" total cross section for the shield which works back to a 0.0247" diameter wire - just a tad smaller than 22AWG. Keep in mind also that when the shield is a power path for currents in central conductors, temperature rise is promoted by BOTH current pathways under a single jacket. I've used shields as return paths for countless, low power or signal pathways but I'd have to think long and carefully about pushing that combination of conductor/insulation to its thermal limits. What application are you considering where you find an advantage in using the shield for this wire as a power-path? Bob . . . ________________________________ Message 5 _____________________________________ Time: 08:04:54 AM PST US Subject: AeroElectric-List: Re: Surplus Wire From: "BMC_Dave" Yeah I got my zeros mixed up there. The shield is equivalent to a single 24ga wire, so that kills the idea. Thanks. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=496913#496913 ________________________________ Message 6 _____________________________________ Time: 06:27:28 PM PST US From: Finn Lassen Subject: AeroElectric-List: Altitude encoder output voltages I want to make a serial to graycode converter to replace the AK350 for input to Garmin GTX 320A transponder. I'd rather have the altitude come from the Dynon D-10A than the AK350 -- no discrepancy between what ATC sees and what I see on the Dynon (at 29.92 alt setting). I found the table on http://www.aeroelectric.com/articles/Altitude_Encoding/modecascii.txt I intend to use an Arduino Nano or similar. But my memory is real vague on the polarity and voltage levels. Is it correct that the encoder has open-collector outputs and the transponder pull-up resistors to system voltage? Does the transponder expect inverted inputs (0 in table no input and 1 in table pulling input to ground)? 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