# US 11,444,446 B2 · Method and device for permanent disconnection of an electrical circuit with an inductive load by switching two switches > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,446 B2 - Document ID: US11444446B2 - Status: Granted - Kind: B2 - Application number: 16/781,003 - Filed: 2020-02-04 - Published: 2020-09-10 - Granted: 2022-09-13 - Earliest claimed: 2019-02-05 - Applicants: Peter Lell - Inventors: Peter Lell - Web page: https://patentgrep.com/patent/US11444446B2 ## CPC - H01H 9/38: Auxiliary contacts on to which the arc is transferred from the main contacts (using arcing-horns H01H9/46) - H02H 3/12: responsive to underload or no-load {(for motors H02H7/0827)} - H01H 39/006: {Opening by severing a conductor} - H02H 1/0007: {concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445)} - 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 device for permanently secure disconnection of an electric circuit with high currents at high voltages with an inductive load is provided. The device has a first and a second switch/switch group, connected to each other in series and can be transferred from a closed state into a separated state for disconnecting the electric circuit, wherein none of the switches/switch groups is formed such that it is capable of permanently disconnecting the electric circuit by itself, and a control unit, which actuates the second switch/switch group and which is formed such that the second switch/switch group is transferred from the closed state into the separated state after the first switch/switch group. Further provided is an electric circuit which includes the device and a voltage source, a load resistance and an inductive load. A method using the device is also provided. ## Claims ### Claim 1 A device for disconnecting an electric circuit with an inductive load, the device comprising: a first switch/switch group and a second switch/switch group connected to each other in series and transferable from a closed state into a separated state for disconnecting the electric circuit, wherein none of the first switch/switch group and the second switch/switch group are configured to securely disconnect the electric circuit permanently by itself; and a control unit configured to actuate the second switch/switch group such that the second switch/switch group is transferred from the closed state into the separated state after the first switch/switch group, wherein: the first switch/switch group and the second switch/switch group are actively transferable from the closed state into the separated state by an actuatable drive, or the first switch/switch group is passively transferable from the closed state into the separated state when the current exceeds a particular nominal value, and the second switch/switch group is actively transferable from the closed state into the separated state by the actuatable drive, and the control unit is further configured to transfer the second switch/switch group from the closed state into the separated state as a function of a particular measured current or a particular measured voltage through the first switch/switch group. ### Claim 2 (depends on 1) The device according to claim 1, wherein the control unit is further configured to actuate the second switch/switch group such that the second switch/switch group is transferred from the closed state into the separated state at, earliest, when so much energy has been absorbed in the first switch/switch group that a remaining amount of energy, which is introduced into the second switch/switch group, does not lead to the destruction thereof. ### Claim 3 (depends on 1) The device according to claim 1, wherein the control unit is further configured to actuate the second switch/switch group such that the second switch/switch group is transferred from the closed state into the separated state, at latest, before an amount of energy introduced into the second switch/switch group is reached which leads to the destruction thereof. ### Claim 4 (depends on 1) The device according to claim 1, wherein the control unit is further configured to transfer the second switch/switch group from the closed state into the separated state when the current flowing through both the first switch/switch group and the second switch/switch group has fallen to a value in the range of from 25% to 40% of the current present at the start of the separation of the first switch/switch group. ### Claim 5 (depends on 1) The device according to claim 1, wherein the control unit is further configured to transfer the second switch/switch group from the closed state into the separated state when the current flowing through both the first switch/switch group and the second switch/switch group has fallen to a value in the range of from 5% to 15% of the current present at the start of the separation of the first switch/switch group. ### Claim 6 (depends on 1) The device according to claim 1, wherein the control unit is further configured to transfer the second switch/switch group from the closed state into the separated state as a function of a particular measured drop in current in the electric circuit. ### Claim 7 (depends on 1) The device according to claim 1, wherein more than two switches/switch groups are electrically connected in series and are actuatable one after the other. ### Claim 8 An electric circuit comprising: a voltage sources; a load resistance; an inductive load; and a device comprising: a first switch/switch group and a second switch/switch group connected to each other in series and transferable from a closed state into a separated state for disconnecting the electric circuit, wherein none of the first switch/switch group and the second switch/switch group are configured to securely disconnect the electric circuit permanently by itself; and a control unit configured to actuate the second switch/switch group such that the second switch/switch group is transferred from the closed state into the separated state after the first switch/switch group, wherein: the first switch/switch group and the second switch/switch group are actively transferable from the closed state into the separated state by an actuatable drive, or the first switch/switch group is passively transferable from the closed state into the separated state when the current exceeds a particular nominal value, and the second switch/switch group is actively transferable from the closed state into the separated state by the actuatable drive, and the control unit is further configured to transfer the second switch/switch group from the closed state into the separated state as a function of a particular measured current or a particular measured voltage through the first switch/switch group. ### Claim 9 A method comprising: disconnecting an electric circuit, the electric circuit comprising: a voltage source; a load resistance; an inductive load; a device comprising: a first switch/switch group and a second switch/switch group connected to each other in series and transferable from a closed state into a separated state for disconnecting the electric circuit, wherein none of the first switch/switch group and a second switch/switch group is configured to securely disconnect the electric circuit permanently by itself; and a control unit configured to actuate the second switch/switch group such that the second switch/switch group is transferred from the closed state into the separated state after the first switch/switch group, wherein: the first switch/switch group and the second switch/switch group are actively transferable from the closed state into the separated state by an actuatable drive, or the first switch/switch group is passively transferable from the closed state into the separate state when the current exceeds a particular nominal value, and the second switch/switch group is actively transferable from the closed state into the separated state by the actuatable drive, and the control unit is further configured to transfer the second switch/switch group from the closed state into the separated state as a function of a particular measured current or a particular measured voltage through the first switch/switch group, the disconnecting the electric circuit comprising: transferring the second switch/switch group from the closed state into the separated state after the first switch/switch group. ### Claim 10 (depends on 9) The method according to claim 9, wherein the second switch/switch group is transferred from the closed state into the separated state, at earliest, when so much energy has been absorbed in the first switch/switch group that a remaining amount of energy, which is introduced into the second switch/switch group, does not lead to the destruction thereof. ### Claim 11 (depends on 9) The method according to claim 9, wherein the second switch/switch group is transferred from the closed state into the separated state, at latest, before an amount of energy introduced into the second switch/switch group is reached which leads to the destruction thereof. ### Claim 12 (depends on 9) The method according to claim 9, wherein the second switch/switch group is transferred from the closed state into the separated state when the current flowing through both the first switch/switch group and the second switch/switch group has fallen to a value in a range of from 25% to 40% of a current present at a start of the separation of the first switch/switch group. ### Claim 13 (depends on 9) The method according to claim 9, further comprising transferring the second switch/switch group from the closed state into the separated state when the current flowing through both the first switch/switch group and the second switch/switch group has fallen to a value in the range of from 5% to 15% of the current present at the start of the separation of the first switch/switch group. ### Claim 14 (depends on 9) The method according to claim 9, wherein the control unit further comprising transferring the second switch/switch group from the closed state into the separated state as a function of a particular measured drop in current in the electric circuit.