There may be specific threads on this, but I haven't found them.
My John Deere voltage regulator (second one) acted up. I was in cruise, about 5200 rpm, (Rotax 912ULS), 3,500'. First leg (1 Hr.) everything was fine. Two hour layover, halfway through second one-hour leg, voltmeter (G3X) flashes red, shows 16.2 volts. Put hand on VR (mounted aft of firewall, passenger side, bolted directly on bottom of shelf, no thermal paste, no blast tube.) VR was so hot I couldn't keep my hand on it. Throttled back substantially, voltage drops some, I flew remaining half hour and landed.
Removing VR showed white wire(s) on B+ terminal had gotten so hot they were melting the black material the spade was set in. Adjacent spade was beginning to melt too. White wire(s) got so hot the insulation was melted up one inch up from terminal. Second photo shows stripped wire which I did NOT pull on. It had to have come out of the crimp as I was removing the VR. Maybe already loose- maybe it was so altered by the severe overheat that the crimp (which might or might not have been sufficiently tight) did not hold it in anymore. (The other wires were tight in their crimps. I used an expensive ratcheting crimper when I installed this VR maybe 30 hours ago. The other crimps were still very tight. I can't imagine I under-crimped the white wire(s), but from other posts, I have seen that loose crimps have caused problems.
Any insights on this event would be appreciated. Has anybody had a similar experience? Was I close to a fire? I am contemplating re-crimping and installing my spare new JD VR WITH thermal paste and a blast tube.
Thanks for your thoughts.
Ben Burbridge
My John Deere voltage regulator (second one) acted up. I was in cruise, about 5200 rpm, (Rotax 912ULS), 3,500'. First leg (1 Hr.) everything was fine. Two hour layover, halfway through second one-hour leg, voltmeter (G3X) flashes red, shows 16.2 volts. Put hand on VR (mounted aft of firewall, passenger side, bolted directly on bottom of shelf, no thermal paste, no blast tube.) VR was so hot I couldn't keep my hand on it. Throttled back substantially, voltage drops some, I flew remaining half hour and landed.
Removing VR showed white wire(s) on B+ terminal had gotten so hot they were melting the black material the spade was set in. Adjacent spade was beginning to melt too. White wire(s) got so hot the insulation was melted up one inch up from terminal. Second photo shows stripped wire which I did NOT pull on. It had to have come out of the crimp as I was removing the VR. Maybe already loose- maybe it was so altered by the severe overheat that the crimp (which might or might not have been sufficiently tight) did not hold it in anymore. (The other wires were tight in their crimps. I used an expensive ratcheting crimper when I installed this VR maybe 30 hours ago. The other crimps were still very tight. I can't imagine I under-crimped the white wire(s), but from other posts, I have seen that loose crimps have caused problems.
Any insights on this event would be appreciated. Has anybody had a similar experience? Was I close to a fire? I am contemplating re-crimping and installing my spare new JD VR WITH thermal paste and a blast tube.
Thanks for your thoughts.
Ben Burbridge
