Cool, so I wonder why anyone would not want the main and backup ignition power source selection automated in this way, Like why experience ANY ignition power failure in flight?
I suppose maybe some manual control for preflight testing is in order but once you are on a takeoff roll it seems like "both" is the correct position for the ignition controls. Half of that bridge rectifier would perform the "both" function for the dual ignition dc power sources for less than $3, while keeping a possibly dead source from draining a still live source. I am assuming a dual dc power source ignition scenario. Maybe need a low volts warning lamp on each dc source, since you may not otherwise be aware of the fault due to no symptom, well, after a while your radios and glass cockpit do shut down.. for me there have been 2 in flight alternator failures. It was the fuel totalizer that died first in the plane that did not have the alternator warning light. Later the radios. The plane with the warning light was a lot better because I immediately shut off all the electrical system to conserve the battery for starting, and used that battery a bunch a times to restart on the way home after fuel and rest stops. After 11 hours flying with no alternator the battery could still restart the motor and power the adsb and transponder under the classB. Both times, thanks to dual magneto's the ride home was a non-event. One of those trips without the alternator took a whole day. I'm pretty sure a battery backup ignition system would not have had such long legs. Also manual powered backup for retractable gear came in handy both times. Cheers! On Wed, Nov 16, 2022, 8:23 AM Jeff York via KRnet <krnet@list.krnet.org> wrote: > Thanks John. I am an Electrical Engineer by degree but have been in > management for many years so I haven't done hands on EE design in some > time. I worked in many capacities from DC controls design to Lithium Ion > systems going back farther than I want to admit. Off subject but its odd > how a person's career goes way off the reservation over time. I eventually > got into ASRS systems (automatic storage and retrieval) and now I am in > management and project management of global systems in the petrochemical > industry . Life, career and single father got me off track on my KR2 and I > am now at a point that allows me to refocus on it. So, I am relearning and > learning all things KR. I am still balancing the father thing as well as > career but at a better place. So, I have lots o dumb questions to ask. > > Jeff > > On Wed, Nov 16, 2022 at 7:11 AM John Gotschall via KRnet < > krnet@list.krnet.org> wrote: > >> Yes, it is a bridge rectifier.. If you use two of the four diodes >> within, you'll have the results I had mentioned. These are cheap and mass >> produced. I have been a full time electronics technician since 1984, never >> have seen one failed. They appear in a lot of equipment in the AC to DC >> power conversion circuits (power supply section). Heavy duty, reliable, >> and dirt cheap. If you check to make sure it's a fast enough part (most >> aren't) they'll make a suitable rectifier for an alternator also. Usually >> they are meant for 120 switching events per second or less as a normal >> speed (60hz). Depending on design an alternator might need to switch >> several thousand times a second (that high pitched whine you might have >> heard). >> >> jg >> >> >> On Tue, Nov 15, 2022, 19:58 Jeff York via KRnet <krnet@list.krnet.org> >> wrote: >> >>> Looks like a high current bridge rectifier >>> >>> Jeff >>> >>> On Tue, Nov 15, 2022 at 7:23 PM John Gotschall via KRnet < >>> krnet@list.krnet.org> wrote: >>> >>>> You can use this (or two diodes, but this is probably more robust and >>>> cheaper) to "steer" the electric power to the ignition system from the >>>> regular and backup power sources. Whichever source has the higher voltage >>>> will power the load without back feeding to the lower voltage source. >>>> There is no switchover time or delay, just a constant feed from the higher >>>> voltage source. Disadvantage: it looses 0.56volts internally which is >>>> generally negligible. >>>> >>>> >>>> jg >>>> >>>> pic attached below. >>>> >>>> >>>> >>>> >>>> On Tue, Nov 15, 2022, 16:00 Jeff York via KRnet <krnet@list.krnet.org> >>>> wrote: >>>> >>>>> I haven't been seeing much activity in the KR group lately so let me >>>>> see if I can stir things up a bit? >>>>> >>>> -- >>>> KRnet mailing list >>>> KRnet@list.krnet.org >>>> https://list.krnet.org/mailman/listinfo/krnet >>>> >>> -- >>> KRnet mailing list >>> KRnet@list.krnet.org >>> https://list.krnet.org/mailman/listinfo/krnet >>> >> -- >> KRnet mailing list >> KRnet@list.krnet.org >> https://list.krnet.org/mailman/listinfo/krnet >> > -- > KRnet mailing list > KRnet@list.krnet.org > https://list.krnet.org/mailman/listinfo/krnet >
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