Patent ID: 6046893
Filing Date: 2000-04-04
Classification: B66D,H02H

Abstract:
In a system including an electric motor and a contact device coupled thereto to by way of at least one power conductor cable, a load limiting device comprising:a shutoff device halting operation of said motor;a first signal conductor coupling a first end of said power conductor cable to said load limiting device;a second signal conductor coupling a second end of said power conductor cable to said load limiting device, said first and second signal conductors carrying a differential load signal representing electric current flow through said power conductor cable;a signal conditioning device receiving said differential load signal and filtering said signal to eliminate frequency components above a given frequency and delivering a stable load signal in a given signal range;a storage device holding a shutoff threshold value; anda comparator receiving said stable load signal from said signal conditioning device and receiving said shutoff threshold value from said storage device, said comparator actuating said shutoff device as a function of the relative values of said received shutoff threshold value and said stable load signal.