Repair welding of a rotating electrical machine's broken shaft

摘要

In a modern industrial practice shafts which suffered various exploitational surface defects from corrosion or wear influences, are generally successfully repaired with commonly used overlay welding or thermal spray techniques. These techniques restore surface integrity and enable continuation of service usage. Shafts that failed due to breaks are however mostly denoted as irreparable and intended for scrap metal. This paper describes, in a case study of a specific DC collector motor, a method of repair welding of a shaft that suffered a fatigue induced break of the front end. Inspection results and various findings obtained after the successful repair welding process, show that the applied technological method is appropriate and yields results in accordance to requirements on integrity and function of a shaft as well as the whole rotating electrical machine. Application of axisym-metric K butt weld joint with dual bevel for repair procedures of various broken shafts, despite requiring more effort for joint preparation compared to a simple butt joints, ensures complete root penetration and therefore a long exploitational life span. The potential of stated repair welding procedure is substantial, since it can be generally applied to shafts of various dimensions, masses and purposes, that have suffered break failures or similar damages. Various axisymmetric bodies could also be repaired using the same procedure. Adapting the butt joint designs and dimensions for other similar applications potentially yield even better results and expand the repair procedure potential. This is, however, subject to further investigations.