Didenko V. Improving safe control of coal face machines effected by power circuit electromagnetic fields

The investigations carried out show that the probability of safe operation is at 0.74, which cannot be sufficient. Mathematical models have been obtained, enabling to relate induced electromotive force in control circuits with electrical parameters of supply system, cable design and coal face machine control. It has been demonstrated that electromotive force is proportional to load current of the machine drive and to supply cable length. Electromotive force can be 6.4 V with actual load current values and cable lengths while induced pulses at the moment of switching power circuits can be as high as hundreds of volts due to capacitance coupling. Measures to provide safe operation of coal face machines under power circuit electromagnetic influence on control circuits have been developed. The measures have been included into safety normative documents for coal face machines and systems, and realized in novel and modified control apparatus and supply cable designs. Key words: coal face machine, control, cable, investigations, induced electromotive force, safety requirements.