INDUCTIVE LOAD WITH PROTECTIVE DEVICE Russian patent published in 1995 - IPC

FIELD: electrical engineering. SUBSTANCE: electric drive includes single-phase electric motor with working and starting windings and electron circuit of control over motor securing functions of starting of motor and of its protection against current overload. sensitive element is current transformer which secondary winding is connected to input of peak detector coupled with output to input of threshold device forming level of voltage of control over operation of logic NOT gate which in its turn controls key connecting starting winding to supply circuit. Starting winding is disconnected immediately after motor achieves rated working mode. In case of long rise of working current oscillations of blocking generator are terminated, keys cut off and both windings are de-energized after time set by counter. There is no mechanical contacts to connect and disconnect proper windings. EFFECT: expanded application field, increased reliability of protection. 2 cl, 2 dwg