During operation, the beater rotates at high speed, forcing the ingredients to mix thoroughly. The ingredients come into full contact with one another and undergo vigorous friction, thereby achieving mixing, emulsification, aeration and the removal of some moisture. As the viscosity of the ingredients being mixed is lower than that of those processed by a dough mixer, the rotational speed of an egg beater is higher than that of a dough mixer, generally ranging from 70 to 270 r/min; it is therefore referred to as a high-speed mixer. Egg beaters Most egg beaters are manual, upright units comprising a mixer, a bowl, a drive mechanism, a bowl lifting mechanism and a base. As for how they are measured and controlled—as you are no doubt aware—measurement and control involve measuring the concentration of the solid-liquid mixture within the bowl, i.e. its viscosity, and controlling the rotational speed of the drive mechanism. The most common method for measuring viscosity is to use an accelerometer. I am not certain what type of sensor is used in this particular machine, but if I were to design it, I would certainly use an accelerometer. Based on physics, we know Newton’s second law: F = ma. Furthermore, the motion of an object varies depending on the viscosity of the liquid; there is a relatively straightforward relationship between the two. The sensor on the rotating mechanism collects viscosity data and sends it to the controller. Through feedback regulation—typically in the form of a voltage signal—the control unit adjusts the rotational speed based on the voltage level. This utilises the concept of negative feedback from the principles of automatic control.
Put simply, when a high concentration is detected, the rotation needs to speed up; once the eggs have been beaten sufficiently, the feedback signal indicates that the concentration has decreased, and the egg beater reduces its rotational speed. So, how does the egg beater determine when the beating is complete? I hope that makes sense.