DEVICE FOR PROTECTION OF ELECTRIC MOTOR FROM NON FULL PHASE MODES AND OVERLOAD Russian patent published in 2007 - IPC H02H7/08 

FIELD: electric engineering, possible use for protecting three-phased asynchronous electric engines from non full phase modes and overloads.

SUBSTANCE: device contains asymmetry indicator for voltages of powering network, first, second and third threshold blocks, signals delay block, supporting voltage block, executing block, first and second current transformers, current sensor for asymmetry of phase currents of electric motor, while for excluding galvanic connection of device and electric network, introduced additionally are: diode optic couple into sensor of asymmetry of feeding network voltages, and into support voltage block - separating transformer. To detect reason of disabling of electric motor introduced additionally is fourth threshold block, which depending on abnormal mode of operation of network or electric motor sends positive impulse to light diodes, indicating reason of disabling of electric motor.

EFFECT: increased reliability and expanded functional capabilities.

2 dwg