Speed detectors

摘要

A speed detector for detecting the speed of a moving body is of the type including a magnetic core, a detection coil wound about the core, a magnet with one pole thereof faced toward the periphery of the detection coil with a definite air gap therebetween, and means for relatively moving the magnet with respect to the core and the coil in accordance with the movement of the moving body. the magnet is arranged such that the magnetic flux produced thereby crosses the detection coil two times, thereby inducing a direct current voltage in the detection coil having a magnitude proportional to the speed of movement of the moving body and a polarity depending upon the direction of movement thereof.