Basic description of Generator and Lane system operation

All my aircraft have momentary start ECU/switches so it is so there is no shutting off needed. However, I have added onto the checklist to turn the Emergency ECU switch on before starting so you have fuel pressure. Then turn it off after starting. I have found they start immediately not having to wait 2 to 3 seconds for fuel pressure to build while cranking the engine. Greater chance of leaving it on.......... 

Peter Avery wrote:

Paul.

We are running a number of 915is engines in our Magni gyros here in NZ.

Through practical testing I can confirm the following.

Gen A failure   both lane lights flash together. With Gen B now powering the engine management system

(EMS) & the battery backup switch turned on a small amount off charge will flow to the battery.

Battery voltage still reducing though , depending on loads.

If Gen A happened to come back on line & resume powering the EMS & Gen B the airframe & battery the lane lights continue to flash until engine shut down . Next start they would act normally.

Gen B failure- No flashing lights but a decline in battery voltage can be seen. Backup power switch on & again a small charge will come to the battery from Gen A.

If Gen B failed & the backup power switch is on & then Gen A failed you will again get both lane lights flashing until shut down. Battery is now powering EMS & airframe loads.

If starting with Gen B failed then the engine will stop when the start power switch turned on is turned off

unless the engine rpm is above 2400/2500 & the EMS is now being run by Gen A.

A bit of a double up with what Jeff has posted, but this is what I have found through failing each generator and operating at various rpm.

cheers

Pete Avery.

Peter, yes this does correlate with what Jeff got, and I also agree with in the Rotax Light warnings. Thanks for doing and providing results here.