2.3.2. Shredding Power Sensor

The shredding rollers are driven by the pulley. The original drive pulley is made of cast iron, and its elastic properties cannot meet the requirements of accurate torque measurement. According to the mechanical dimensions of the original cast iron pulley, 40CrNiMoA high-strength alloy steel material with better inherent elastic properties is selected to design a pulley-type shredding torque and speed sensor, as shown in Figure 2.

**Figure 2.** Physical view of shredding power sensor. 1: elastic pulley; 2: mounting base; 3: torque sensor; 4: speed sensor.

The sensor mainly consists of three parts: an elastic pulley, a torque-sensing component, and a speed-sensing component. The elastic pulley is utilized to replace the original cast iron pulley, providing the mechanical connection and power transmission for shredding rollers. The torque sensor component includes a resistive torsion strain bridge, a signal acquisition circuit, a signal output circuit, etc. The speed sensor component includes an inductive speed sensor mounted with tiny round screw threads, a speed probe mounting hole, and a speed measuring panel with 30 detection points equally distributed along the

circumference. The inductive speed sensor is fixed on the sensor shell at a distance of 1.0 mm from the speed panel, and while as the disc rotates, the speed sensor continuously outputs pulses.
