My engine panel overspeed alarm is driven by the freq output from the
alternator from the AC taps. The overspeed alarm goes off when the
alternator speed is 5000rpm, equiv to engine speed 2300rpm. With a new
alternator, I've reduced the pulley size considerably and the alt speed
is 5000 rpm at 1400 engine rpm - and the alarm now goes off.
The engine panel has a pot to adjust the overspped freq but looking at
the service bulletin the freq will be outside its adjsutment range
I've got 2 options - the easy one - disconnect the wire - is an
overspeed really necessary or useful??
Try and get a device to divide the frequency.

Grateful for any ideas.