Abstract: In a stone cutting machine having a cutting chain rotated by a motor and a separate power feed for the machine, the power consumption of the drive motor is monitored. When the power consumption falls below a minimum, a control signal is generated to increase the feed, and when the power consumption exceeds a fixed maximum, a control signal is generated to decrease the feed. In generating the control signal, the power consumption is scanned only over a pre-determined period, which for power consumption beneath the minimum is approximately twice as long as for the power consumption above the maximum.