could be my experience has been with different motors...
but I've tested some, and in the past built lots of little wind turbines from them, and once hooked one to a gas engine thinking it'd make a cool battery charger.
I'd say 0-15 amps, and anytyhing much over 10 for a sustained period of time will burn them up.
On the gas engine, I was using the larger version (a 7" long case vs 5" long), I think it was rated 40 volts (and these ones are definitely more powerful than the smaller ones)... at 10 amps output it quickly got
HOT.
I've never seen 30 amps from one, but I guess in extreme winds I've seen upwards of 20, but it wouldnt do that for long.
I think they make real nice wind turbines, but I'd not expect average outputs much more than 50 watts with peaks of perhaps 150.