An example electrical machine is described that includes active segments for variable voltage generation. The electrical machine includes a drive shaft, a fixed rotor segment, an active rotor segment, and an actuator mechanism. The fixed rotor segment is coupled to the drive shaft, where the fixed rotor segment has affixed thereon first permanent magnets of alternating polarity. The active rotor segment axially is adjacent to the fixed rotor segment along the drive shaft. The active rotor segment also has affixed thereon second permanent magnets of alternating polarity. The actuator mechanism is configured to articulate the active rotor segment relative to the fixed rotor segment and thereby alter a phase of the second permanent magnets relative to the first permanent magnets in order to change a first voltage generated by the electrical machine to a second voltage generated by the electrical machine.