Running a genny or an alternator? The alternator needs to spin up before it will charge. The Regulator type only. No 1 wire in the mix. The regulator thinks the system is ready to charge, the volts are too low and the contact is opening and closing as fast as it can. That is the "buzz". Rev the engine and see if it quits. It stopped? All is good. Still buzzing? Get a solid state regulator. It will look the same and has no moving parts. Make sure the output volts are correct for the system(typical 12 Volt at the battery during "charge" is 14.5 Volts) Generator out put is different at start up. The regulator was made for a generator. It works for that alternator but it was made for the generator.

Steve H