DEVICE FOR CONTROL OVER ELECTRIC MOTOR DRIVE Russian patent published in 1995 - IPC

FIELD: electrical engineering. SUBSTANCE: device is designed for asynchronous electric drive of hoisting mechanism. It includes frequency converter, phase-pulse control unit, control unit on frequency of supply network, regulator, conductance pickup, current tester, unit for frequency setting, thyristor switch, time delay unit, voltage pickup unit with filters of first harmonic components and rectifirer, formers of output frequences equal correspondigly to (1/3m)·f_n.s и (2/3)·f_n.s,, where m is one of terms of natural series 1, 2, 3, 4,..., f_n.s is frequency of supply network. EFFECT: diminished surges of current and rotational speed while accelerating drive to rated speed and while braking. 8 dwg