Gens Ace 90A esc
#3
I had to do a search for a picture of it. Does it have any type of connector? On a guess, it might be used for governor with some helicopter flight controls? I would say wrap it up, tuck it away and not worry about it. What does the manual say it is?
Buzz.
Buzz.
#5
Connect battery to ESC and check voltage at the little red wire. If voltage equals the battery voltage, the wire may be an accessory that can be used for a "spark avoidance" circuit that avoids the big spark when a large voltage battery is first plugged into the ESC.