A duplicated system comprises two identical circuits, each designed for full load, with the changeover to standby power provided automatically. A sectionalizer, when one of the circuits is damaged, automatically connects the consumer to the serviceable 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.