PTO spline shaft torque transducers ± 5 000 N·m

PTO: torque and speed by telemetry, with removable splined ends

The PTO measures the torque and the speed of a power take-off shaft. Its female spline mates with the PTO shaft of the machine, its male spline with the implement, and both splines lock. The splined ends can be removed and changed: type 1 (1 3/8 in, 6 teeth), type 2 (1 3/8 in, 21 teeth) and type 3 (1 3/4 in, 20 teeth). The telemetry transmitter excites the strain gages, amplifies and digitizes the torque signal and transmits it by radio, at 3 kHz for a 1 kHz bandwidth. A 60 pulse per revolution tone wheel and a Hall effect sensor give the speed. A non-rotating aluminum stator, aligned on the transducer by a large sealed bearing, carries the primary induction coil, the receiving antenna and the Hall effect sensor. Full scale is ± 2 500 or ± 5 000 N·m, with non-linearity and hysteresis below 0.5 % of full scale. It weighs 5.8 kg with a 1 3/8 in spline.

The transducer goes on the PTO shaft and the implement on the transducer, with no modification to either. An anti-rotation eye-hook keeps the stator from turning. Induction power and the receiver take 11 to 15 V DC, 3.0 A max. The transducer operates from −40 to 105 °C and the receiver box from 10 to 77 °C. It is delivered pre-calibrated, and its weatherproof construction allows field and long-term testing.

It is used to measure the mechanical power that a tractor delivers to the implement during field work, as an input to tractor transmission development.