Electric rotating machine standards part II: Magnetic wedge design & monitoring methods

The proper application of motors requires the exchange of design data sheets. The American Petroleum Institute Standard API 541, 4th Edition, is the premier document on how to specify electrical induction motors. This paper will address one application failure in which the user did not apply the motor in accordance with API standards. This paper will review procedures for monitoring temperatures, acoustical emissions, and vibration changes to detect pending failures. Further, it will analyze recent developments in wedge material and shapes, and new online monitoring methods used to detect winding abnormalities caused by loosening slot wedges. Finally, the paper will examine the resulting energy savings and overall benefits of specifying magnetic slot wedges.