Control and limitation of maximum permissible rotor speed in laboratory centrifuge

摘要

The method controls and limits the speed of a laboratory centrifuge. A sensor (7) scans an information medium (6) fastened to the rotor, from which signal, the maximum permissible speed is evaluated by a processor (9) under programmed control. On overspeed the rotor drive is shut down. In addition, from the start up behaviour of the rotor (1) used, its moment of inertial is determined analytically. This is used to determine the speed limit from a standard relationship. The values read and determined, are compared. In the event of a difference, drive is shut down. Also claimed is the corresponding control system including a circuit to detect and evaluate the energy absorption by the drive, or current flow to it, during run-up. This is used to calculate the moment of inertia.