Abstract: Owing to its good starting-up and smooth speed regulation performances, the DC motor is so widely used in various fields. Nevertheless, in case of the DC motor-based drive system for the inlet roller conveyor of the hi-speed cut-off machine, errors concerning both the DC motor and the drive system proper occur very often due to such negative elements like one motor-to-mutli-roller drive arrangement and poor site conditions, etc. Described in the article are the modification of frequency conversion of the said roller conveyor drive system and the result.