Acoustic signature inspection of railroad wheels

摘要

The disclosure concerns an electromagnetic exciter for striking the wheels of moving railroad cars undergoing acoustic signature inspection. The apparatus comprises a pivotally mounted impact member which is accelerated by a solenoid through only a portion of its impact stroke and then moves onward to impact solely as a result of the kinetic energy imparted to it during the initial acceleration period. The solenoid is controlled by an electronic drive circuit which responds to an input signal from a wheel presence detector and delivers to the solenoid coil a burst of energy whose size and duration may be adjusted to yield the greatest sound pressure level while allowing the field of the coil to relax quickly enough to reset the apparatus for the next car wheel.