---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 08/28/22: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:19 PM - Re: 30A PM alternator and Z101? (johnbright) 2. 06:32 PM - Re: flyback diode across fuel pump (johnbright) ________________________________ Message 1 _____________________________________ Time: 06:19:56 PM PST US Subject: AeroElectric-List: Re: 30A PM alternator and Z101? From: "johnbright" nuckolls.bob(at)aeroelect wrote: > At 09:14 PM 6/10/2022, you wrote: > > Not exactly a precision test instrument. Next time > you talk to him, suggest that I can plot efficiency > and performance curves with some degree of confidence > along with quantification of the 'spike' theory. > > . . . suitable NDA provided . . . of course. > > Bob . . . Hi Bob, I have communicated by email and telephone with Bill Judge of Monkworkz. I passed along your offer of doing performance testing and evaluation of the spike that trips OV protection if the B lead is disconnected under load. At present Bill plans to keep testing in house. Present Monkworkz documentation shows the B lead connected downstream of the master contactor. Perhaps Bill will come up with a recommended Z101 implementation. I shared my brainstorm configurations from post 9 with him. Bill has a customer who connected the B lead to the battery using a relay independent of the master contactor and has hit the OV protection by opening the relay under load. This does not happen with the B lead connected downstream of the master contractor. Per Bill: Why does this happen? Well, there are inductors inside the regulator, you can't instantaneously change the current in an inductor, the current has nowhere to go and causes a spike. That spike gets mopped up by a massive (1.5kW) TVS diode on the output but that doesn't kick in until the voltage goes over ~16 V, and the OVP kicks in at 15.3 V. The generator has nothing to do with the spike. The output of the generator is rectified and sent through a voltage converter, the voltage converter is causing the spike. -------- 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/folderview?id=1u6GeZo6pmBWsKykLNVQMvu4o1VEVyP4K Read this topic online here: http://forums.matronics.com/viewtopic.php?p=507803#507803 ________________________________ Message 2 _____________________________________ Time: 06:32:56 PM PST US Subject: AeroElectric-List: Re: flyback diode across fuel pump From: "johnbright" nuckolls.bob(at)aeroelect wrote: > At 09:57 PM 8/25/2022, you wrote: > > > > > Someone on VAF suggested putting a flyback suppression diode across fuel pump leads like we do with contactor and relay solenoid coils. This was re an automotive fuel pump like SDS/EFII/Airflow Performance/Walbro. > > > > What say Bob et Al? > > Did the author cite a noise problem which was > mitigated by adding this component? > > I'm mystified by any assertion of added value. > Rotary pumps powered by pm motors have no > 'flyback' event. PutPut pumps like the > Facet devices have electronically driven > solenoids that 'cock' a compression spring. > A cruise through the genealogy of exemplar > patents for such pumps . . . > > https://tinyurl.com/2e6mmzyr (https://tinyurl.com/2e6mmzyr) > > . . . illustrates commonly applied > technology for mitigating flyback > energies in these devices that include > resistors, diodes and capacitors as > part of the designs dating back over > 30 years. > > I'm curious as to the history of > the thread. > > > > Bob . . . > > Un impeachable logic: George Carlin asked, "If black boxes > survive crashes, why don't they make the whole airplane > out of that stuff?" Hi Bob, The VAF thread started as local ground or forest of tabs for fuel pump ground?, EFI fuel pump, and drifted at post 9 to someone recommending a diode across the pump motor to protect the pump switch. I had never heard of this so I asked here on AEL. https://vansairforce.net/community/showpost.php?p=1629894&postcount=9 -------- 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/folderview?id=1u6GeZo6pmBWsKykLNVQMvu4o1VEVyP4K Read this topic online here: http://forums.matronics.com/viewtopic.php?p=507804#507804 ------------------------------------------------------------------------------------- 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.