A Noncontacting Torquemeter

A noncontacting torquemeter was constructed which used two magnetic pickups to detect the angle of twist between two gears mounted on a spring-steel shaft. Electronic circuitry measured the phase shift between the signals from the magnetic pickups. The phase shift was proportional to the twist in the shaft and, therefore, to the transmitted torque. The torquemeter accurately measured torque in a shaft rotating at 391 to 651 rev/min. The upper and lower limits to shaft speed were not investigated, but the time constant of the circuit would not allow speeds below 6 rev/min.