Use of an electromagnetic speed changing device, such as linear motor or/and eddy current retarder, for speed measurement

摘要

The method involves arranging movable magnetic portion (16) relative to the induction portion (14). The time characteristic curve is detected to detect induced electrical measurement value in induction portion. Two consecutive characteristic points in time characteristic curve are selected. The temporal distance for characteristic points is determined. The dimension of the magnet portion is assigned and stored in memory device (37) corresponding to characteristic points, for determining relative speed of magnetic portion and induction portion. An independent claim is included for device for determining relative speed of movable elements.