Speed control device for electric motor, has comparator permitting to control motor to operate in self guided operating mode or external guided operating mode by determining difference between actual and target speeds of rotor

摘要

The device has a rotational speed comparator (2) provided with signals representative of target and actual speeds of a rotor of an electric motor (4). The comparator permits to control the motor through a flip flop (17) and a field vector-position counter (24) to operate the motor either in self guided operating mode or external guided operating mode by determining a difference between the speeds.