Alternator honks horn!

[Jeff Erwin]

OK, here's a new one. well for me anyways. Working on my 71 Bee. Battery is out, been out and over there for about 3 weeks. I was removing the alternator yesterday, preparing for a new dash harness that requires a 1-wire. As I was removing it, I bumped it against the two horns on the inside fender.

The horns went off! Honked for about 2 seconds before I pulled the alternator away.

My suspicion is that the alternator somehow stores power, but I don't think there are any capacitors in there that would store that much power. I 'think' I may have felt a tingle as I removed the alternator, but I could have imagined that part.

What gives? Ghost in the machine?

 

[Rusty 72]

Put a voltmeter on it and see if it has power? It must've if it set the horns off? New one to me also.

 

[Jeff Erwin]

Did that once I got it on the bench. Nothing. Residual current in the windings maybe? Is that a thing?

 

[Rusty 72]

Definitely residual somewhere in the Alt. You probably discharged whatever was there when it connected with the horn. Weird.

 

[RJRENTON]

Definitely residual somewhere in the Alt. You probably discharged whatever was there when it connected with the horn. Weird.

IMO....most original Mopar alternators (round back and square back designs) used an internal capacitor, usually connected to, or part of, the alternator's output connection stud. Whether this capacitor can retain enough voltage to power the horn for a couple of seconds is ???? Just a thought.....
BOB RENTON