Re: Alt at 12 amps until it's revved up then 14 amps
The "exciter" is the internal regulator. The internal regulated alternators are set to not charge until they reach a set rpm determined by engine rpm's. After they get to tht rpm, and "catch", they stay at the maximum charge voltage until the system is shut down again, as in engine stop. Then, when the engine starts all over again, the same process is repeated.
If the charge voltage falls below the maximum voltage after the regulator catches, check the regulator being defective. Usually, the regulator catch is between 1,100 and 1,300 rpm's, which is actuated by the cold start choked engine, or, the first rev the engine gets above the capture rpm when hot.
I have spun up a lot of these alternators for my local auto parts store ( do a lot of that for them, nobody else knows how to doit there), and I can watch one that is working right actually catch and run when I run them up at first run on the machine. Most are at, or very near the 1,100 rpm level.