What method is used to resolve residual magnetism to an exciter?

Flashing the field is the correct method used to address residual magnetism in an exciter. This procedure involves applying a brief burst of direct current (DC) to the exciter's field windings, which helps to realign the magnetic field and eliminate any residual magnetism that may have built up during operation or when the exciter was not in use.

Residual magnetism can prevent the exciter from operating correctly when it is started, affecting the overall functionality of the generator system. By performing this flashing process, the exciter can be re-energized properly, ensuring that it can generate the necessary voltage for the generator's operation.

The other methods, while relevant to various maintenance and operational tasks, do not specifically address the issue of residual magnetism in the exciter. Grounding the system is primarily for safety and protection against fault conditions. Resetting the circuit usually pertains to restoring the operation of an electrical circuit after a trip or a malfunction, and calibrating the motor involves adjusting its performance metrics to meet specifications, but none of these directly pertain to resolving magnetism issues in an exciter.