DEVICE FOR QUASI FREQUENCY CONTROL OF THE SPEED OF ASYNCHRONOUS MOTORS

摘要

The device is designed for making conventional electric drive systems for mechanical handling, textile, toolmaking and other machines for industry. It has reduced number of contact connections and asymmetry, specific reversing and improved reliability and it can secure output voltages having frequencies f = fmp/n, where n=1,3,...11, operating at preset optimum criteria. Information is retrieved from memory for obtaining three-phase voltage system of reduced frequency at optimum adjustment criterion. The device contains a matching unit (1), generator (2), digit control unit (3), enabling pulse formation unit (4), power unit (5) connected to the asynchronous motor (6), counter (7), memory (8), signal identification unit (9) and simistors (10, 11 & 12).