When the first hot slab slides onto the entry conveyor of a hot‑rolling line, the power supply located in the drive cabinet switches on the inverter that drives the main roll motors. Its constant, clean energy feed allows the PLC and sensor network to keep the speed and torque of each roll tightly coordinated, preventing surface defects and reducing waste. Because the rolling process demands rapid changes in motor speed as the slab length varies, the supply must react instantly to the control signals, keeping the drive electronics alive even during sudden load spikes caused by material thickness changes. The same unit also feeds the cooling‑water pump and the position‑feedback encoders that monitor roll alignment, so the whole section can be brought up or down without manual intervention. In adjacent furnace automation, the same type of supply powers the temperature‑control panels that regulate burners, guaranteeing that the melt temperature stays within tight limits before the slab reaches the rolling stands.