A duplicated system includes two identical circuits, each of which is designed for full load, while the transfer to standby power is provided automatically. The sectionalizing switch, in the event of damage to one of the circuits, automatically connects the consumer to the healthy circuit. ...

As is known, the load of downhole electric motors has a sharply variable character. When calculating the cable network, it should be based on the maximum performance of downhole machines and mechanisms. Therefore, the choice of the mode of calculation of the sectional cable network is especially important. For this purpose it is necessary to know the required voltage at different modes of operation of the main motor, which in the conditions of a coal mine section is the motor of the combine or cutting machine.