Lee A Hughes

US Patent:

40327663, Jun 28, 1977

Filed:

May 17, 1976

Appl. No.:

5/686880

Inventors:

Lee E. Hughes - Bellevue WA
John L. Marshall - Renton WA
Dieter Doring - Seattle WA

Assignee:

Tally Corporation - Kent WA

International Classification:

G06F 1100
H02H 338

US Classification:

235153AS

Abstract:

A wide range current flow fault detector comprising a current sensor and a selective interrogator are disclosed. Current flow, or the lack thereof, between a power supply (e. g. , capacitor bank) and a load (e. g, the hammer coils of a line printer) is sensed by a current sensor connected to detect the voltages at spaced points along a selected length of the supply conductor connecting the power supply to the load. A differential amplifier forming a part of the current sensor produces an output voltage related to the voltage difference between the selected points. The output voltage of the differential amplifier is compared, in a comparator, with a preset voltage. Any time the output voltage of the differential amplifier is above the preset voltage, the output of the comparator changes from a first state (e. g. , low) to a second state (e. g. , high). At all other times, the output of the comparator remains in the first state.