The switching between low-speed and high-speed power supply modes during operation is automatic, requiring no additional electromechanical control devices. The working principle is analyzed as follows:
In the low-speed range, due to the generator's low rotational speed, the series connection of the three-phase windings boosts the output voltage, thereby significantly enhancing the generator's charging performance at low speeds. In the high-speed range, as the generator's rotational speed increases, the inductive reactance of the series-connected three-phase windings rises, leading to an increased internal voltage drop; furthermore, the intensified armature reaction causes the output voltage to decline. At this stage, the original three-phase windings (A, B, and C)-characterized by a relatively smaller internal voltage drop-generate a comparatively higher induced current, thereby ensuring robust power output at high speeds.
