For a timely replacement of the bearing, breakdown of which bear heavy impact, it is necessary to carry out or which is much better continuous control of its state. A few bearings are usually installed on the general shaft and in one body. In this case the external circuits turn out to be electrically connected through the body, the internal ones - through the shaft. The necessity to create electrical contact between assembly details, one of which is rotating, considerably aggravates the measurement. In particular, it excludes practically the possibility of built-in control due to low reliability of electric contact.

The method was developed for bearings diagnostics without electric contact usage in assembly units. The essence of it is in current creation in electrically closed contour consisting of the body, shaft and bearings. It occurs due to inductance coil with closed ferromagnetic core embracing the shaft. The inductance coil is connected with ac generator. Due to the action of the alternative magnetic flux concentrated in the close magnetic conductor, current is induced in electrically close contour. Current value is practically determined by electric resistance between external and internal rings of bearings. Parameters of induced current are measured by means of the second inductance coil similar to the first one and connected with the measurement block.