Fast disconnects for generator systems

In accordance with at least one aspect of this disclosure, a system includes a generator control relay configured to electrically connect a generator and an exciter switch drive to drive an exciter switch. A first processor is operatively connected to control a state of the generator control relay to control the electrical connection between a generator and the exciter switch drive. The system includes an exciter drive configured to generate excitation current for field windings of a generator system based on a state of the exciter switch. A second processor is operatively connected to control the exciter drive and to communicate with the first processor during a fault event to place the generator control relay in an open state, disconnecting the generator from the exciter switch drive to prevent generation of excitation current. In certain embodiments, the first processor can include a microcontroller and the second processor can include a voltage regulation processor.