William P Monaghan

US Patent:

52552080, Oct 19, 1993

Filed:

Aug 8, 1991

Appl. No.:

7/742035

Inventors:

Prashant B. Thakore - Library PA
John L. Coulter - Leechburg PA
William D. Monaghan - Dravosburg PA

Assignee:

AEG Westinghouse Transportation Systems, Inc. - Pittsburgh PA

International Classification:

G06F 1100

US Classification:

36455101

Abstract:

A method and apparatus for on-line diagnostics, particularly for use in power circuits of a DC-DC converter is described. Signals are sensed at selected strategic test points in a circuit and compared with stored expected signals for those points under normal operating conditions. Whenever the signals sensed at the selected test points do not correlate with the corresponding expected signals, the sensed signal is compared with abnormal signals stored in the memory associated with known failure conditions for that test point. Whenever the sensed signal matches closely with a signal for a known failure condition, an indication of the particular failure is logged into memory. If the sensed signal does not match a known failure condition, an indication of an unknown failure condition is logged into memory. Failure information can later be retrieved by maintenance personnel at a convenient time or can be displayed on an operator's display during operation.