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US 6,788,515 B1Granted
Over-current control
AssigneeG & W Electric Company
InventorDonald R. Martin
Life of this patent
Estimating the term…
Abstract
An over-current control device, either single or three phased, is provided for protecting equipment and persons under fault conditions. The control device incorporates integrated circuitry to provide over-current protection to monitored circuits/components. The preferred embodiments of the device include time/current characteristic circuitry and trip circuitry to cause the contacts of a relay to transition, thereby actuating a magnetic latch and providing either direct or indirect over-current control.
Claims4
An over-current control device comprising:
- a step-down transformer;
- a rectifier for rectifying the output of the transformer;
- a time/current characteristic circuit wherein the time rate of voltage increase and decrease simulates the thermal characteristics of the time-to-melt in a fuse element and the time-to-reset in a circuit breaker, said time/current characteristic circuit being connected to the output of the rectifier;
- a minimum trip level circuit responsive to said time/current characteristic circuit and comprising a voltage-monitoring integrated circuit chip and a first switching device, wherein said integrated circuit chip transitions from a low output state to a high output state based on a threshold voltage level sensed at the input of the integrated circuit chip, thereby controlling said switching device;
- and
- a tripping circuit responsive to said minimum trip level circuit and comprising a second switching device, stored energy means and a latching relay, wherein said latching relay is controlled by said second switching device and is powered by said stored energy.
3 more elements
Dependencies are inferred from the claim text.