The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 20, 1999
Filed:
Sep. 03, 1997
Masaaki Eguchi, Saitama, JP;
Nikkiso Co., Ltd., , JP;
Abstract
A wear monitoring device for a motor employs pairs of coils on each end of a motor stator. The coils face the rotor and are sensitive to the gap between the rotor and the stator. Each pair of coils is interconnected in series to generate a differential output. Each pair of coils is positioned opposite the other of the pair so that when, as a result of bearing wear, the gap increases between one coil of a pair and the rotor and decreases between the other coil of the pair, a signal is generated on the output. Since the coils are positioned at a separation of 180 degrees and interconnected to produce a differential output, the fundamental-harmonic voltage is canceled out in the differential signal. The differential signal corresponding to pairs of coils located on opposite axial ends of the stator are applied in parallel through respective diodes to a voltage indicator. Thus the voltage indicator is responsive to bearing wear causing the rotor axis to tilt with respect to the stator axis. In another embodiment, the differential outputs are interconnected in series to a voltage indicator. In this embodiment, the voltage indicator responds to axial displacement of the rotor. In another embodiment, the differential outputs of two pairs of coils are applied through respective diodes to an indicator in series while the differential outputs of another two pairs of coils are applied in parallel so that rotor-tilting and axial displacement caused by bearing wear are indicated.