The ALSPA CDL8000 type frequency converter with rated power up to 5.4MVA serves preferably to continuous speed adjustment of single low-voltage asynchronous motors. These drive systems are used in particular for pumps and fans, but also for centrifugal systems, presses, belt conveyers and cranes. High-speed drives up to 12000 rpm, such as for gearless compressors, is another example of application. The simple functioning principle of the ALSPA CDL8000 makes it possible without additional technical measures to brake the drive electrically, to regenerate its energy and to change its rotating direction (4-quadrant operation). The ALSPA VDM6000, ALSPA VDM7000 and ALSPA CDM8000 types are avalaible for medium voltage motors.