# US 7,612,972 B2 · Electrical contractor current sensing system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,972 B2 - Document ID: US7612972B2 - Status: Granted - Kind: B2 - Application number: 11/240,990 - Filed: 2005-09-30 - Published: 2007-04-05 - Granted: 2009-11-03 - Earliest claimed: 2005-09-30 - Assignees: Rockwell Automation Technologies, Inc. - Inventors: Jeffery John Battani; Ping Soon Lee - Web page: https://patentgrep.com/patent/US7612972B2 ## CPC - H01H 83/14: operated by imbalance of two or more currents or voltages, e.g. for differential protection - H01H 50/021: {structurally combining a relay and an electronic component, e.g. varistor, RC circuit (auxiliary switch inserting resistor during closure H01H50/543)} - H01H 71/123: {using a solid-state trip unit (circuits H02H)} - H01H 50/045: {Details particular to contactors (H01H50/042 takes precedence)} - H01H 83/02: operated by earth fault currents (H01H83/14 takes precedence) - H02H 3/347: using summation current transformers - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) ## Abstract A current sensing module is provided for contactors and similar switch gear. The current sensing module is packaged so as to be capable of mounting on a line or a load side of a contactor. The current sensing module may be eliminated where current signals are not needed, but can be added to the package where monitoring and control functions may benefit from sensed current signals on either or both sides of a contactor. The current sensing module may be configured as a single or multiple-phase device, and may output either analog or digital signals to local devices or to networked devices. ## Claims ### Claim 1 A current sensing electrical contactor system comprising: a contactor assembly including a housing, moveable contacts, stationary contacts and a control coil configured to cause movement of the moveable contacts to open and close a current carrying path through the moveable and stationary contacts in response to a control signal, the contactor being only remotely operated to open and close the current carrying path; a current sensing module assembly mechanically coupled to an outer face of the housing wherein the current sensing module assembly includes: a plurality of current sensors for sensing current through at least two current carrying paths defined by the moveable and stationary contacts; and a ground fault sensor adapted to sense current through at least two conductors and generate a signal indicative of a ground fault; and a relay coupled to the current sensing module assembly and configured to apply or interrupt power upstream of the contactor in response to current sensed by the current sensing module assembly. ### Claim 2 (depends on 1) The system of claim 1, wherein the contactor assembly is a three phase contactor. ### Claim 3 (depends on 1) The system of claim 1, wherein the current sensing module assembly is configured to be physically coupled interchangeably to either a line side or a load side of the contactor assembly. ### Claim 4 (depends on 1) The system of claim 1, further comprising an analog-to-digital converter for converting current signals from the current sensing module assembly to digital values. ### Claim 5 (depends on 4) The system of claim 4, further comprising a network interface circuit for transmitting the digital values to a remote location via a network link. ### Claim 6 A current sensing electrical contactor system comprising: a contactor assembly including a housing, moveable contacts, stationary contacts and a control coil configured to cause movement of the moveable contacts to open and close a current carrying path through the moveable and stationary contacts in response to a control signal, the contactor being only remotely operated to open and close the current carrying path; a modular current sensor assembly physically coupled to an outer face of the housing and including: a plurality of current sensors configured to sense current through at least two current carrying paths defined by the moveable and stationary contacts; and a ground fault sensor adapted to sense current through at least two conductors and generate a signal indicative of a ground fault; and a relay coupled to the modular current sensor assembly and configured to independently apply or interrupt power upstream of the contactor assembly in response to current sensed by at least one of the plurality of current sensors. ### Claim 7 (depends on 6) The system of claim 6, wherein the current sensor assembly is configured to be physically coupled interchangeably to either a line side or a load side of the contactor assembly. ### Claim 8 (depends on 6) The system of claim 6, further comprising an analog-to-digital converter for converting current signals from the current sensor to digital values. ### Claim 9 (depends on 8) The system of claim 8, further comprising a network interface circuit for transmitting the digital values to a remote location via a network link. ### Claim 10 A current sensing electrical contactor system comprising: a modular current sensor assembly configured to be physically coupled to an outer face of a contactor assembly and including a plurality of current sensors configured to sense current through at least two current carrying paths defined by the moveable and stationary contacts; a ground fault sensor adapted to sense current through at least two conductors and generate a signal indicative of a ground fault; and a relay coupled to the modular current sensor assembly and configured to apply or interrupt power upstream of the contactor assembly in response to current sensed by the modular current sensor assembly. ### Claim 11 (depends on 10) The system of claim 10, wherein the current sensor assembly is configured to be physically coupled interchangeably to either a line side or a load side of the contactor assembly. ### Claim 12 (depends on 10) The system of claim 10, further comprising an analog-to-digital converter for converting current signals from the current sensor to digital values. ### Claim 13 (depends on 12) The system of claim 12, further comprising a network interface circuit for transmitting the digital values to a remote location via a network link.