Abstract:Drive shaft status monitoring is an important part of the health management of power machinery equipment. The realtime acquisition of speed and torque is its primary step and data foundation. Aiming at the problems of sensor installation, signal transmission, realtime and continuity in status monitoring, this paper proposes a batteryfree and leadless realtime measurement method based on roundcapacitive grid. The structure and principle of the round capacitive grid are described. The principle of capacitive coupling signal transmission is analyzed. The differentialcombinationconfiguration and installation method of the round capacitive grid are given.The optimal number of round capacitive grid electrodes is determined by simulation as 20. Finally, the speed and torque measurement of the drive shaft is carried on the turbo pump hydraulic test bench. The speed waveforms at 300 and 600 r/min and the waveforms corresponding to three different torque values at 300 r/min are obtained. Five different time points are selected during the experiment, the speed and torque datas collected at each time point by the round capacitive grid and the strain gauge torque sensor are compared, and the data consistency is good. The experimental results show that the round capacitive grid can be used to measuring the torque of the drive shaft.