I got my machine in last week and its alternator which is a bosh 12 v 120 a was not working. I got a new one and pit it on but after reving up she was producing 17.9 volts. I returned the alternator and am waiting on a replacement. The alternator looks like this one http://www.fleetalternatorstarter.com/alternator_10385.aspx the guy at the desk tried to tell me that the alternator probably does not have a voltage regulator built in. I pointed out the round electrical device separated by the ceramic insulator. So my question is there a external voltage regulator and if so where is it located, I am only asking as I want to make sure I am not waiting on more parts down the road.
The link for the alt you posted has an "internal" regulator, it clearly states it also. I'm sure your alt also has an internal reg. You should read about 14.5 volts.
That add says internally regulated, so if that's the same alternator/part number then it doesn't have an external voltage regulator. I don't know Case specifically, lots of people here can answer what a 590 should have. When replacing an alternator, always charge up the batteries first, clean any suspicious connections, and maybe check the voltage drop under load if you get a voltage like that (assuming that was NOT at the battery terminals?) Theoretically, an alternator could be designed to put out that voltage IF certain wires had too much resistance, the battery was half charged, and it was cold.
The black box with the red wire is probably the regulator. It's connected to one of the rotor brushes and it completes the circuit thru the rotor windings, so it will charge....
Thanks guys I thought it was self regulated. I put it on with clean connections and a fully charged battery. It was just a bad alternator