Governor, or a mechanical stabilizer The problem of shaft rotation speed stabilization in transport and production machinery is one of the earliest ones and provided with variants of solution. Governor, or a movable double ball wheel, is one of such mechanical stabilizers. It consists of two balls placed on movable rods connected with a common shaft. The regulator allows setting of a definite shaft rotation speed due to its fixation at a greater or a lower height. Besides, a regulator with movable arms without a fixing device can be used. In this case upon achieving the maximum speed the balls of the differential lever get into the farthest position from the shaft. In this position the wheel shows maximum resistance to rotation. Such devices gained popularity at the time of steam engines implementation and were in demand over a hundred and fifty years. Besides mechanical engineering, they were used in the middle of the 20th century in construction of speed stabilizers in gramophones and compact magnetic tape recorders. They were called centrifugal regulators.