---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 12/15/11: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:00 AM - Re: starter switch wiring (racerjerry) 2. 08:29 AM - Re Auto Aux Fuel Pump Circuit Idea (James Kinninger) 3. 03:00 PM - Use of non-aviation Ford-style regulators (Paul Millner) 4. 05:18 PM - Re: Use of non-aviation Ford-style regulators (David) 5. 08:04 PM - Re: Auto Aux Fuel Pump Circuit Idea (Fred Stucklen) 6. 09:34 PM - Purpose of Diodes on Relays (Victor Menkal) 7. 10:42 PM - Re: Purpose of Diodes on Relays (David Lloyd) ________________________________ Message 1 _____________________________________ Time: 07:00:32 AM PST US Subject: AeroElectric-List: Re: starter switch wiring From: "racerjerry" Most likely you are just reading the magneto internal coil resistance. Disconnect the P leads and re-measure. You will still see continuity between the magnetos P lead terminal and ground with P leads disconnected. The magnetos coils primary winding consists of a small number of turns of wire wrapped around an iron core. One end of the primary winding is internally grounded and the other end is connected to the P terminal/stud. The resistance of the primary winding is very low (not much more than the meter lead resistance) and difficult to measure using a standard ohmmeter. Slick specifies primary coil resistance to be between 0.5 and 1.2 ohms (points open / disconnected). With your ohmmeter, verify that each bare P lead (aircraft wiring) has continuity between each lead and ground when magneto switch is in the OFF position and OPEN (no continuity) when in the BOTH position. If that works, reconnect everything, fire up the engine and do a normal magneto RPM drop check to verify all is well. -------- Jerry King Read this topic online here: http://forums.matronics.com/viewtopic.php?p=360955#360955 ________________________________ Message 2 _____________________________________ Time: 08:29:11 AM PST US From: James Kinninger Subject: AeroElectric-List: Re Auto Aux Fuel Pump Circuit Idea The original topic seems to have gravitated to the area of vapor locks and pump placement. That is fine with me and actually makes my below information applicable. Here is my question to Don Rivera of Airflow Performance (the maker of my Aux pump & kit) and his answer: My question was: " I have return lines to each wing tank. These lines go through an Andair Value that when turned, changes both the out going line from the tank as well as the return line. So, can I hook up your boost pump to take advantage of the plumbing I have in place or should I abandon it and the expensive Andair Valve?" Don's response, Nov 19, 2011: "It would not be advisable to run separate return lines to each tank when using this boost pump package. Simply tee the return line into the supply line feeding the boost pump. You can put a tee fitting on the outlet of the selector valve then on the run of the tee, connect that to the inlet of the boost pump. Connect the return line from the pump to the tee part of the fitting on the selector valve. You can use your trick Andair selector valve for the purge return (that=92s the valve on top of the engine). Due to vapor issues it is not advisable to install the boost pump on the engine side of the firewall (a gascolator is also not advisable to be installed on the firewall). This is far more a flight safety issue than installing the boost pump with =93high pressure fuel=94 (30 PSI is not high pressure) in the cockpit. If the plumbing is installed correctly and aircraft fuel system practices are followed for plumbing (reference AC4313-2B) there should be no problem." Don Rivera Airflow Performance 111 Airflow Drive Spartanburg, SC 29306 Phone: 864-576-4512 Fax: 864-576-0201 E-Mail: don@airflowperformance.com website: airflowperformance.com Jim Kinninger jimk@hdiss.net ________________________________ Message 3 _____________________________________ Time: 03:00:31 PM PST US From: Paul Millner Subject: AeroElectric-List: Use of non-aviation Ford-style regulators Note that it can be dangerous to use non-aviation Ford-type regulators in our airplanes.When the alternator half of the master switch is turned off, the regulator will allow the alternator to go into a voltage runaway mode, and that overvoltage will not be controlled by your overvoltage relay (since the field current is flowing via a separate path, directly from the alternator).The overvoltage condition can cook your avionics and battery. Even if you don't turn off the alternator half of the master switch, if your separate overvoltage relay trip for any reason with such a regulator installed, that, ironically, will trigger the voltage runaway scenario. Paul ________________________________ Message 4 _____________________________________ Time: 05:18:39 PM PST US From: David Subject: Re: AeroElectric-List: Use of non-aviation Ford-style regulators Uh oh. What's the protection for this? I'm using not a Ford, but a smaller, denser, lighter Japanese alternator with same output. David Merchant Paul Millner wrote: > > Note that it can be dangerous to use non-aviation Ford-type regulators > in our airplanes. When the alternator half of the master switch is > turned off, the regulator will allow the alternator to go into a > voltage runaway mode, and that overvoltage will not be controlled by > your overvoltage relay (since the field current is flowing via a > separate path, directly from the alternator). The overvoltage > condition can cook your avionics and battery. > > > Even if you don't turn off the alternator half of the master switch, > if your separate overvoltage relay trip for any reason with such a > regulator installed, that, ironically, will trigger the voltage > runaway scenario. > > > Paul > -- Tell the truth. Be honest. Be responsible to and for yourself. I liked America when it was free and it's people were responsible and had morals. Every gram of cocaine you buy from elsewhere contributes to an innocent being murdered in Central and South America. Grow your own or Stop taking it. ________________________________ Message 5 _____________________________________ Time: 08:04:20 PM PST US Subject: AeroElectric-List: Re: Auto Aux Fuel Pump Circuit Idea From: "Fred Stucklen" I've given some more thought and testing on the Auto Aux Fuel Pump idea that I originally posted. I've attached a schematic of a circuit I've bread boarded and tested. Seems to to work. The idea/implementation is to automatically turn the pump ON for as long as the fuel pressure is below a set limit, and don't turn it off until the pressure has been above that limit for at least 10 seconds. If the pressure go low again, the process is repeated. I'm planning on making up a hardwired proto board and actually testing in my RV-7A, but probably not until after the new year..... Fred Stucklen RV-7A N924RV 650 Hrs Read this topic online here: http://forums.matronics.com/viewtopic.php?p=361007#361007 Attachments: http://forums.matronics.com//files/auto_aux_fuel_pump_704.pdf ________________________________ Message 6 _____________________________________ Time: 09:34:15 PM PST US From: Victor Menkal Subject: AeroElectric-List: Purpose of Diodes on Relays I noted that the manufacturer of my ignition switch requests a diode across the between the excitation (low current start switch) input and ground. Also noted that Bob calls out diodes on fig Z-16 wiring diagram for the Rotax 912. Can anyone provide a simple explanation of reason for these? As well Bob did not call out the diode on Z-16 but assume its the same as the other drawings which calls for a 1N5400 diode. I really like Bob's crow bar over voltage module and alternator disconnect relay which is not included in the standard Rotax wiring schematic. Low cost and easy to install (following Bob's schematic of course) and covers off one problem area which a number of Rotax owners have identified with the standard wiring system and rectifier. Best part is that my ALT switch on the panel is now gainfully employed (not used following standard Rotax diagram). Over voltage protection option is also highly recommended by the Rotax guru's at Rotec Research Canada. Thanx Vic CH750 Rotax 912ULS-2 Whitehorse Yukon ________________________________ Message 7 _____________________________________ Time: 10:42:44 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Purpose of Diodes on Relays Not sure if this is what your are looking for.... The diode on some ignition switches provides a small current to the alternator field to insure that the field gets excited upon start up. Some alternators do not self start and need a little current to begin the generation process... Dave ------------------------------------------------------------------------- ------- ----- Original Message ----- From: Victor Menkal To: aeroelectric-list@matronics.com Sent: Thursday, December 15, 2011 9:26 PM Subject: AeroElectric-List: Purpose of Diodes on Relays I noted that the manufacturer of my ignition switch requests a diode across the between the excitation (low current start switch) input and ground. Also noted that Bob calls out diodes on fig Z-16 wiring diagram for the Rotax 912. Can anyone provide a simple explanation of reason for these? As well Bob did not call out the diode on Z-16 but assume its the same as the other drawings which calls for a 1N5400 diode. I really like Bob's crow bar over voltage module and alternator disconnect relay which is not included in the standard Rotax wiring schematic. Low cost and easy to install (following Bob's schematic of course) and covers off one problem area which a number of Rotax owners have identified with the standard wiring system and rectifier. Best part is that my ALT switch on the panel is now gainfully employed (not used following standard Rotax diagram). Over voltage protection option is also highly recommended by the Rotax guru's at Rotec Research Canada. Thanx Vic CH750 Rotax 912ULS-2 Whitehorse Yukon ------------------------------------------------------------------------------------- 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.