This paper describes an automated test system for piezoelectric motors
allowing the experimental characterization of its electromechanical b
ehaviour. In the first part, an experimental method is given for evalu
ation of losses generated in the different mechanisms of conversion: e
lectric energy into ultrasonic vibrating energy and ultrasonic vibrati
ng energy into mechanical energy of revolving motion. in the second pa
rt, the present method is experimentally validated on a travelling-wav
e-type rotary motor (Shinsei USR-60). The free stator vibration is ana
lysed by a laser vibrometer which gives a picture both of amplitude an
d of phase vibration. This result allows one to obtain an identificati
on of vibrations modes and an evaluation of ultrasonic vibrating energ
y and electromechanical efficiency. To characterize the working of the
complete motor, the no-load working mode is first considered. The mea
surement of its maximal mechanical characteristics (maximal no-load ro
tating speed, maximal driving torque) with respect to axial load allow
s the choice of optimum axial load. For this optimum value, the load w
orking mode is, finally, investigated for the evaluation of load chara
cteristics and conversion losses.