We had massive ~35° V-shaped steel rotors with blades in the body to disintegrate fat lighter stumps. They were about 8' in diameter and god only knows what they weighed. Operators watched an ammeter and held a dead man's switch in their hand for the 6' wide conveyor belt feeding the hopper for the "hogs". They would feed stumps into the hog and pretty much overload the hog and watch for the ammeter to drop back to the unload shaft amps before hitting the button to deliver another load. These were powered by ~900HP 460VAC motors. The antique starter overloads were cast iron grids that would get red hot under heavy loads and occasionally burn out. They got to be a pretty good judge about max loading as an overload burnout took several hours to clear and affected production which was to be avoided. You may want to incorporate a mA meter as part of the display.