DEVICE FOR CONTROL OF THREE-PHASE AND SINGLE-PHASE LOADS BY POWER FOUR-WIRE NETWORK

摘要

FIELD: electrical engineering.;SUBSTANCE: invention relates to electrical engineering, in particular, to control electric motors of borehole pumps and heaters of external water pipelines. Device comprises at the input of power transmission line protective device, three-phase magnetic starter, contacts of which are connected to three-phase load connected at the end of power transmission line, to outputs of which three capacitors connected in star with artificial zero point, between which and neutral wire of network is connected heater, and at the beginning of the line, the ambient temperature sensor is connected through an auxiliary opening contact of the three-phase magnetic starter with the contactor coil, the contact of which shunts the contact of the first or second phase of the three-phase magnetic starter, and in the zero-wire cross-piece there is a current relay which is actuated during heater operation when the electric motor is disconnected, at that, the first "heater operation" signal lamp is lit. Current relay is also triggered when one of the phases breaks off when the motor is running or at its start, then two-coil double-relay memory relay is actuated, first contact of which disconnects power of three-phase magnetic starter coil, second contact supplies power to second signal lamp "phase failure", third contact sends signal to operational personnel. Circuit is returned to the initial state by supplying power to the second winding of the memory relay with a button.;EFFECT: technical result consists in improvement of load control device reliability.;1 cl, 1 dwg