The progress of semiconductor technology and control systems the last years has made possible the realisation of highly efficient and low priced microprocessor-based controllers for the control of asynchronous motors. This paper describes the design and realization of a microcomputer-based device for frequency regulation of an asynchronous motor. Through the regulation of motor's supply frequency is achieved regulation of its speed. The control is based on PWM method, with voltage feedback, and frequency regulation is performed in the range of 20Hz to 60 Hz. The application platform is an automatic industrial press machine in a machines constructions company.