DEVICE PROTECTING ELECTRIC MOTOR OF SUBMERSIBLE PUMP AGAINST CURRENT OVERLOADS Russian patent published in 1999 - IPC

FIELD: protection of electric pumps against emergency operating conditions. SUBSTANCE: device protecting electric motor of submersible pump against current overloads includes unit converting three-phase supply current of electric pump to output voltage proportional to it, threshold element, element disconnecting electric pump, circuit delaying disconnection of electric pump by time depending on value of emerging current overloads made up of three integrating RC networks with different time constants connected with one end to input of threshold element through diode assembly and with other end to different sections of output voltage divider of conversion unit. In this case less values of voltages of divider go to integrating RC networks whose time constants are smaller. Device makes it feasible to shorten downtime of electric pump thanks to generation of long delay in disconnection of electric pump allowed by overload characteristic of electric motor of submersible pump under insignificant current overloads. EFFECT: shortened downtime of electric pump. 3 dwg