| 摘要 |
FIELD: electric tape drives of sound-recording devices. SUBSTANCE: controlled valve-type electric motor has electromechanical frequency changer with permanent-magnet inductor and armature winding whose coils are connected to output of frequency changer built as voltage inverter, logical control unit, comparators, two groups of integrating circuits, and voltage limiters. Integrating circuits and voltage limiters provide for shaping signals across comparators output of 180 deg, length, spaced 120 deg apart, and symmetrical relative to rotational emf signal. Logical unit actuated by these signals ensures sequential ON/OFF operation of switches in anode and cathode groups of frequency changer to connect armature winding coils to power supply from time to time. Motor is started in synchronous mode. While motor is running, rotational emf is induced in its armature winding coils which speeds up change-over processes of comparators. Motor is switched over to position commutation mode. In speed control mode, control signal applied to additional input of frequency changer is varied depending on load. Integrators connected across inputs of comparators maintain balanced operation of comparators at different control currents relative to rotational emf. EFFECT: reduced pulsations of electromagnetic torque; improved service life of motor. |
