In synchronous motors, as the DC amperage increases, what happens to the AC amperage?

In synchronous motors, the relationship between DC amperage and AC amperage is driven by how the motor is designed to operate, particularly with regards to field excitation. When the DC amperage that energizes the rotor's field winding increases, the strength of the magnetic field produced by the rotor also increases.

As the magnetic field becomes stronger, it influences the rotor's capacity to maintain synchronism with the stator's rotating magnetic field. This allows the motor to produce the required torque more effectively. However, the nature of synchronous motors means that the AC amperage required to maintain operation does not necessarily increase directly with the DC amperage. Instead, the motor operates more efficiently, keeping the AC amperage constant relative to the added strength of the magnetic field.

Therefore, the correct answer reflects that the AC amperage remains constant due to the stabilizing influence of the motor's rheostat, which regulates the current flow and ensures that the system operates within its designed parameters. This relationship is fundamental to understanding synchronous motor operation and efficiency.