APPARATUS AND METHOD FOR DETERMINING CLEARANCE OF MECHANICAL BACK-UP BEARINGS OF TURBOMACHINERY UTILIZING ELECTROMAGNETIC BEARINGS

摘要

Apparatus and method for determining the clearance and wear of mechanical back-up bearings of turbomachinery utilizing electromagnetic bearings. In order to reduce the prospects of catastrophic failure during a shut-down or loss of electrical power, a rotating apparatus utilizes the electromagnetic bearings to manipulate the shaft to measure the clearance of the mechanical back-up bearings. When power is restored, a programmable controller provides power to the electromagnetic bearings to automatically move the shaft in accordance with a predetermined sequence to contact the mechanical back-up bearings to determine the clearance of the mechanical back-up bearings. These values are stored in the controller memory. The measured clearance is compared to prior clearance measurements of the mechanical back-up bearings to determine the wear of the back-up bearings. The actual wear is compared to the allowable wear for the bearings. If actual wear exceeds a predetermined value, a warning is generated. If the actual wear equals or exceeds the allowable wear, the controller automatically locks the turbomachinery from further operation until repair or replacement is accomplished. Otherwise, the controller centers the shaft to permit normal operation of the turbomachinery.