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:
Dec. 13, 1994
Filed:
Mar. 17, 1993
Konrad Kulczyk, Frimley, GB;
Solartron Group Limited, , GB;
Abstract
A speed or torque probe comprises a permanent magnet havings its north-south axis extending radially of a bladed rotor, so that the tips of the blades pass in close proximity to one pole of the magnet, and a T-shaped pole piece. A first portion of the pole piece, corresponding to the upright portion of its T-shape, extends tangentially of the rotor, with its free end in contact with the other pole of the magnet, while the other portion of the pole piece, corresponding to the cross-piece of its T-shape, again extends radially of the rotor. As a result, the magnet, the first portion of the pole piece and the half of the other portion nearer to the rotor form a variable magnetic circuit, such that the passing rotor blades induce eddy currents in a first coil wound upon the half of the other portion of the pole piece nearer to the rotor. A second coil is wound on the half of the other portion of the pole piece further from the rotor, and connected in opposition to the first coil, so that voltages induced by stray external magnetic fields in the first coil tend to be cancelled by those induced by these same fields in the second coil.