DEVICE FOR PROTECTION OF THREE-PHASE ELECTRIC MOTOR AGAINST OVERLOAD AND SHORT-CIRCUIT CURRENTS IN OUTGOING POWER CIRCUITS Russian patent published in 2025 - IPC H02H7/08 

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, in particular to devices providing protection against emergency modes of electric motors. Device for three-phase electric motor protection against overload and short-circuit currents in outgoing power circuits consists of a housing made in the form of two compartments connected by means of cable inputs, each of the compartments is equipped with a door on each of which there are external control elements of the device operation; a detachable control panel is also located on one of the doors. Inside the housing there is a high-voltage automatic switch with functions of zero protection, protection against short circuit, thermal protection and protection against overloads, to the input of which the mine power supply network is connected, an electrically controlled vacuum contactor connected to an electric motor is connected to the output of the switch. Device also has an insulation resistance monitoring module which is connected to the power circuit of the electric motor and to circuits intended for supplying external devices; a leakage monitoring module for monitoring leaks to earth, which is connected to a contactless zero-sequence current transformer; current control module, which is connected to contactless current transformers; motor temperature control module is connected to motor temperature sensor circuits. All information from the insulation resistance control module, the leakage control module for the earth leakage control, the current control module, the electric motor temperature control module is supplied to the central processing module, which is also connected to the communication modules with external control elements. Connection of external equipment is carried out by means of quick-disconnect connections, which make it possible to perform switching without disconnection of power supply, simultaneously providing explosion-proof device, and electrical equipment, which is part of device, is placed in explosion-proof enclosure, where cable entry points are equipped with explosion-proof elastic rubber rings.

EFFECT: creation of explosion-proof equipment providing protection of three-phase electric motor against overload and short-circuit currents in outgoing power circuits in underground workings of coal mines and mines saturated with methane and/or coal dust.

7 cl, 1 tbl, 6 dwg