Fixtures and processes for magnetizing magnetoelastic shafts circumferentially

The present invention relates to an apparatus and method for magnetizing a shaft, and more particularly to an apparatus and method for circumferentially magnetizing magnetoelastic torque transducer shafts for providing a measure of torque applied to the shaft. An apparatus and method for magnetizing a shaft in a circumferential direction is provided in which electrical current is applied to one or more electrical current conduction tubes and is directed through the tube to at least one coupler having an internal diameter sized so as to circumferentially contact the exterior diameter of a part of the shaft to be magnetized. An electric current pulse is applied to the electrical current conduction tube and radially enters the shaft from the coupler associated with the tube at a substantially 90° degree angle to the axis of the shaft. The current is forced axially along the length of the shaft in the direction of at least a second coupler to magnetize one or more bands along the shaft in a circumferential direction. The current exits the shaft by way of the second coupler and a second electrical conduction tube.