# US 10,746,610 B2 · Safety circuit, a safety circuit operation method and an electrically operated motor comprising a safety circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,746,610 B2 - Document ID: US10746610B2 - Status: Granted - Kind: B2 - Application number: 15/739,516 - Filed: 2016-06-29 - Published: 2018-07-05 - Granted: 2020-08-18 - Earliest claimed: 2015-07-02 - Assignees: BITZER Electronics A/S - Applicants: Lodam electronics a/s - Inventors: Claus Marcussen - Web page: https://patentgrep.com/patent/US10746610B2 ## CPC - G01K 15/007: {Testing} - G01K 3/005: {Circuits arrangements for indicating a predetermined temperature (fire detection G08B17/00)} - G01K 15/00: Testing or calibrating of thermometers - G01K 15/005: {Calibration} - G05D 23/30: Automatic controllers with an auxiliary heating device affecting the sensing element, e.g. for anticipating change of temperature - H02H 7/08: for dynamo-electric motors - H02H 7/0852: {directly responsive to abnormal temperature by using a temperature sensor (in a control circuit H02H7/0833)} - H02H 3/05: with means for increasing reliability, e.g. redundancy arrangements {(for logic circuits H03K19/003)} - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - 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 safety circuit for temperature tripping with redundancy is disclosed. The safety circuit comprises a first temperature evaluation module comprising a first input arranged to receive a first input signal derived from a temperature by means of a temperature-dependent element; the first temperature evaluation module further comprising a first output arranged to provide a first output signal corresponding to said determined first temperature state. The safety circuit further comprises a second temperature evaluation module comprising a second input arranged to receive a second input signal derived from said temperature by means of said temperature-dependent element, the second input signal being different from said first input signal; the second temperature evaluation module further comprising a second output arranged to provide a second output signal corresponding to said determined second temperature state. The safety circuit further comprises a tripping monitoring unit connected to said first and second outputs and being arranged to establish a tripping command signal when at least one of said first and second output signals changes to a trip state. A safety circuit operation method and an electrically powered motor comprising the safety circuit are further disclosed. ## Claims ### Claim 1 A safety circuit for temperature tripping with redundancy, the safety circuit comprising: a first temperature evaluation module comprising a first input arranged to receive a first input signal derived from a temperature by means of a temperature-dependent element; the first temperature evaluation module being arranged to evaluate said first input signal and determine a first temperature state as one of at least two states, whereof at least one state is a trip state; the first temperature evaluation module further comprising a first output arranged to provide a first output signal corresponding to said determined first temperature state; a second temperature evaluation module comprising a second input arranged to receive a second input signal derived from said temperature by means of said temperature-dependent element, the second input signal being different from said first input signal; the second temperature evaluation module being arranged to evaluate said second input signal and determine a second temperature state as one of at least two states, whereof at least one state is a trip state; the second temperature evaluation module further comprising a second output arranged to provide a second output signal corresponding to said determined second temperature state; and a tripping monitoring unit connected to said first and second outputs and being arranged to establish a tripping command signal when at least one of said first and second output signals changes to said trip state. ### Claim 2 (depends on 1) The safety circuit according to claim 1, wherein said first input and said second input are connected to different terminals of said temperature-dependent element. ### Claim 3 (depends on 1) The safety circuit according to claim 1, wherein said temperature-dependent element comprises at least one thermistor. ### Claim 4 (depends on 1) The safety circuit according to claim 1, wherein said temperature-dependent element comprises two terminals, and by series-coupling between two resistors forms a voltage divider with two taps for providing said different first and second input signals. ### Claim 5 (depends on 1) The safety circuit according to claim 1, wherein said first temperature evaluation module is arranged to perform said determining said first temperature state based on a first reference value, and said second temperature evaluation module is arranged to perform said determining said second temperature state based on a second reference value different from said first reference value. ### Claim 6 (depends on 5) The safety circuit according to claim 5, wherein said first and second temperature evaluation modules comprise different reference sources (26, 36) to establish said different first and second reference values (25, 35), respectively. ### Claim 7 (depends on 1) The safety circuit according claim 1, wherein said tripping monitoring unit is arranged to establish said tripping command signal by forcing a trip signal output with a voltage level denoting “high” to change to a voltage level denoting “low”. ### Claim 8 (depends on 1) The safety circuit according to claim 1, wherein the safety circuit comprises or is communicatively coupled to an electrically operated switch, controlled in response to said tripping command signal; and wherein said temperature-dependent element is located in an electrically powered load and wherein said electrically operated switch is arranged to disconnect said electrically powered load in response to said tripping command signal. ### Claim 9 (depends on 1) The safety circuit according to claim 1, wherein the safety circuit comprises two or more first and second inputs arranged to receive two or more first and second input signals, respectively, derived from two or more respective temperatures by means of two or more respective temperature-dependent elements so that each pair of a first and second input signal relates to the same of said two or more temperatures and is connected to different terminals of the same of said two or more temperature-dependent elements; the first and second input signal of each pair being different. ### Claim 10 A safety circuit operation method for temperature tripping with redundancy, the safety circuit operation method comprising the steps of: providing a first input signal derived from a temperature by means of a temperature-dependent element; processing the first input signal by a first temperature evaluation module, the processing comprising determining a first temperature state as one of at least two states, whereof at least one state is a trip state, and providing a first output signal corresponding to said determined first temperature state; providing a second input signal derived from said temperature by means of said temperature-dependent element, the second input signal being different from said first input signal; processing the second input signal by a second temperature evaluation module, the processing comprising determining a second temperature state as one of at least two states, whereof at least one state is a trip state, and providing a second output signal corresponding to said determined second temperature state; establishing a tripping command signal when at least one of said first and second output signals changes to said trip state. ### Claim 11 (depends on 10) The safety circuit operation method according to claim 10, wherein said first input signal and said second input signal are connected to different terminals of said temperature-dependent element. ### Claim 12 (depends on 10) The safety circuit operation method according to claim 10, wherein said temperature-dependent element comprises at least one thermistor. ### Claim 13 (depends on 10) The safety circuit operation method according to claim 10, wherein said temperature-dependent element comprises two terminals, and by series-coupling between two resistors forms a voltage divider with two taps for said providing said different first and second input signals. ### Claim 14 (depends on 10) The safety circuit operation method according to claim 10, wherein said processing by said first temperature evaluation module uses a first reference value to determine said first temperature state, and said processing by said second temperature evaluation module uses a second reference value different from said first reference value to determine said second temperature state. ### Claim 15 (depends on 10) The safety circuit operation method according to claim 10, wherein said step of establishing said tripping command signal comprises forcing a trip signal output with a voltage level denoting “high” to change to a voltage level denoting “low”. ### Claim 16 (depends on 1) The safety circuit operation method according to claim 1, wherein the method further comprises a step of operating an electrically operated switch on the basis of said tripping command signal; and wherein said temperature-dependent element is located in an electrically powered load, and wherein said method comprises a step of disconnecting said electrically powered load in response to said tripping command signal by means of said electrically operated switch. ### Claim 17 (depends on 10) The safety circuit operation method according to claim 10, wherein the method further comprises providing two or more first and second input signals derived from two or more respective temperatures by means of two or more respective temperature-dependent elements so that each pair of a first and second input signal relates to the same of said two or more temperatures and is connected to different terminals of the same of said two or more temperature-dependent elements; the first and second input signal of each pair being different. ### Claim 18 (depends on 17) The safety circuit operation method according to claim 17, wherein the method comprises processing said two or more first input signals by said first temperature evaluation module, the processing comprises determining said first temperature state as said trip state when at least one of said two or more first input signals evaluates to said trip state; and processing said two or more second input signals by said second temperature evaluation module, the processing comprises determining said second temperature state as said trip state when at least one of said two or more second input signals evaluates to said trip state. ### Claim 19 An electrically powered motor comprising a safety circuit for temperature tripping with redundancy; the safety circuit with redundancy comprising: a first temperature evaluation module comprising a first input arranged to receive a first input signal derived from a temperature by means of a temperature-dependent element; the first temperature evaluation module being arranged to evaluate said first input signal and determine a first temperature state as one of at least two states, whereof at least one state is a trip state; the first temperature evaluation module further comprising a first output arranged to provide a first output signal corresponding to said determined first temperature state; a second temperature evaluation module comprising a second input arranged to receive a second input signal derived from said temperature by means of said temperature-dependent element, the second input signal being different from said first input signal; the second temperature evaluation module being arranged to evaluate said second input signal and determine a second temperature state as one of at least two states, whereof at least one state is a trip state; the second temperature evaluation module further comprising a second output arranged to provide a second output signal corresponding to said determined second temperature state; and a tripping monitoring unit connected to said first and second outputs and being arranged to establish a tripping command signal when at least one of said first and second output signals changes to said trip state; and said electrically powered motor further comprising at least one temperature-dependent element of which one terminal is connected to said first input of said safety circuit and another terminal is connected to said second input of said safety circuit. ### Claim 20 (depends on 19) The electrically powered motor according to claim 19 comprising an electrically operated switch arranged to disconnect said motor from one or more supply phases in response to said tripping command signal of said safety circuit.