A complete profile of automatic acceleration for an analytic ultracentrifuge is established with an electronic speed control system. Motor current is controlled by a Sola (resonant transformer) resonant current source during acceleration and when the rotor reaches full speed the Sola saturates, forming a constant voltage regulator. As full speed is approached, a closed loop system is introduced which compares the frequency of a magnetic‐geartooth counter to a reference circuit and then applies the error as voltage increments to the drive motor. To evaluate performance, a computer program was developed to compare manual control with the automated system. Results indicate greater accuracy in the automated system for the integrated &ohgr;2dtduring the acceleration phase of ultracentrifuge operation, and extremely stable and accurate control of final speed (to within 10 ppm or less).