Model emcd 4000 rahw is a special purpose system designed for crack detection in bearing races and ring shaped components, incorporated by pune-based magnafield. The system constitutes of 5 major assemblies, control console, circular magnetization station, longitudinal magnetisation station, and magnetic bath tank and inspection station. For detection of longitudinal cracks, high intensity magnetising current upto a max of 4000 amp half wave dc is passed through a central conductor and for transverse cracks the race is subjected to a strong toroidal field generated by transient currents. Movement of central conductor for circular magnetization and jaws of magnetic core for longitudinal magnetization is functioned by electronically controlled pneumatic system. In each case the race retains a strong residual magnetism after application of current shot. Two separate examinations are required. After each type of magnetization, the job is dipped into a black circulating magnetic bath for a few seconds. The cracks are inspected under conventional tube light. A demagnetiser is provided on the inspection station for effectively demagnetizing the race after test. The machine is suitable for testing races upto 200 mm od, 100 mm width and 60 mm min id. Specifications are as follows: power: 415v - 3ph - 50hz - 100 a intermittent compressed air: 5 kg/cm2.
