Abstract: An alternator or synchronous generator, principally for supplying electrical current to batteries and other apparatus in cars, ships, aeroplanes and other devices for transport. The alternator consists primarily of a hollow stator with windings of which the inner shell is conical, a rotor with a conical outer shell which operates in conjunction with the conical inner shell of the stator, a shaft which rotates in the housing of the alternator, a slide between the shaft and the rotor for the axial motion of the rotor over the shaft and in the stator for the purpose of current control, a device for sliding the rotor over the shaft into the stator, a device for sliding the rotor over the shaft out of the stator, and, on the rotating shaft a centrifugal voltage controller for fine-adjusting the means which slides the rotor out of the stator and keeps the induced current voltage the same.