US Patent 8229682 Apparatus and method for bearing condition monitoring

An electrical motor bearing condition monitoring system includes an assembly that includes a shaft, a first bearing race coupled to the shaft, a plurality of bearing balls, and a second bearing race coupled to the first bearing race via the plurality of bearing balls. A portion of the assembly has a magnetic field encoded thereon. The monitoring system includes a magnetic field sensor positioned proximately to the magnetized assembly and configured to measure the magnetic field, and a processing unit configured to detect changes in the magnetic field via the magnetic field sensor.