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. 19, 1983
Filed:
Jul. 13, 1981
Richard W Mattson, Rossford, OH (US);
Allied Corporation, Toledo, OH (US);
Abstract
A critical brush wear circuit for a dynamoelectric machine which is not sensitive to stray voltages and currents resulting from brush dust accumulation within the machine, and which may be used over a wide range of voltages, is disclosed. The brush wear detection circuit is provided with a novel memory device shown as a latching relay, formed by two conventional relays disposed perpendicular to each other, with the armatures of each disposed to perpendicularly overlap a portion of the other armature and latch it in energized position when it has been moved to energized position by energizing its coil. One relay is provided with contacts for disabling the coil of the other relay, so that the other relay coil is automatically de-energized after a momentary period of connection, so that it can be allowed to draw high current, since it is not connected long enough for damaging heat to occur. In the preferred embodiment of the invention, the memory device or latching relay receives a critical brush wear signal from an insulated wire embedded in a brush of the dynamoelectric machine, and is provided with two co-wound coils on a common core for connection to brushes of opposite polarities. The memory device or latching relay provides a critical brush wear warning by eliminating a lamp on the memory device package itself, and at a lamp at a central location, connected to several such memory devices for several dynamoelectric machines.