A piezoelectric motor has peak performance at a specific frequency f. sub. 1 that may vary over a range of frequencies. A drive system is disclosed for operating such a motor at peak performance without feedback. The drive system consists of the motor and an ac source connected to power the motor, the ac source repeatedly generating a frequency over a range from f. sub. 1 -. DELTA. x to f. sub. 1 +. DELTA. y.