Bob is correct! Both the A & B type have the
field circuit NC (normally connected).
The A Type Field Terminal is (NC) connected to "Ground" via both the current & voltage Relays.
The B Type field Terminal is (NC) connected to the Armature Terminal via both the Current & Voltage Relays.
This regulation method is one of the bad features of a Generator. The Generator has residual(uncontrollable)Magnetism and must be Turned-off (regulated) by "reducing" the field current. Its akin to controlling the speed of your Car using the brakes, with the Gas Pedal floored.
Most PLL know better then to Short the +ve (Pos)& -ve (neg) posts of a battery but they don't consider that when the wires or contacts are smaller. The Smaller wires or relay contacts have near the "SAME" potential, as the Battery Posts, and will try to supply the >150 amps but will self destruct.
This is why PLL that play with the regulator Field Terminal damage the Regulator &/or the wiring.