EFII Bus Manager Failure - What would it look like?

[majuro15]

I'm working through my electrical design and contemplating failure modes analysis. My question is when using the EFII injection and ignition system, what would an inflight complete power failure look like of the bus manager after an E-buss switch is thrown?

For example, stable flight, primary power distribution device (Bus Manager) fails. Switch the 30A rated switch which would then connect the ECU's/coils/fuel pumps directly to a battery. Will the engine immediately restart? ECU's have to reset? Fuel pump reset? What would the restart procedure be?

I am aware of the functions of the bus manager and triple redundancy, but considering not using the bus manager switch and wiring in an independent switch.

[bret]

This is how I wired mine, bus A fuse block, one ecu, pump, ign coils, the other set on bus fuse block B, and bus C for all avionics and what have ya, I have two batteries one on the master relay, and through a different firewall pass through, back up battery going through a 30A switch that feeds bus A and B, a heavy switch controls bus C a schotsky heat sink diode feeds the backup battery. I have 7 switches for the EFII system.

[rcpaisley]

Hi Tim,
The Emergency Power switch function of the Bus Manager is a completely separate circuit with its own Oring of both batteries to the Essential Bus.

If the normal current path through the Bus Manager shut off for some reason,
flip the Emergency Power switch for alternate power routing and the engine would instantly be alive without further intervention. The engine will never actually stop turning (unless you stall the plane), it would be windmilling until the systems regained power. As soon as electrical power is available the engine would resume running and making power without any delay.

Robert Paisley

[majuro15]

Thanks for the response Robert. My main question I guess is if the ECU's would take time or if it'd fire right back up as long as the prop is windmilling.

I'll be in touch soon for a full system!

[rcpaisley]

Hi Tim,
The engine would light back up in a fraction of a second. There is no discernible delay,
Robert