# US 2014/0152329 A1 · Insulation Monitoring Device With Measuring Circuit Interruption > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152329 A1 - Document ID: US20140152329A1 - Status: Published application - Kind: A1 - Application number: 14/094,126 - Filed: 2013-12-02 - Published: 2014-06-05 - Earliest claimed: 2012-12-04 - Assignees: Bender GmbH & Co. KG - Applicants: Bender GmbH & Co. KG - Inventors: Wolfgang Hofheinz - Web page: https://patentgrep.com/patent/US20140152329A1 ## CPC - G01R 31/52: Testing for short-circuits, leakage current or ground faults - G01R 1/206: {Switches for connection of measuring instruments or electric motors to measuring loads (switches in general H01H)} - G01R 1/36: Overload-protection arrangements or circuits for electric measuring instruments - G01R 27/02: Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) - G01R 27/18: Measuring resistance to earth {, i.e. line to ground} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract The invention relates to an insulation monitoring device that forms a measuring circuit with an unearthed IT power supply system for monitoring an insulation resistance, wherein the measuring circuit can be interrupted by a breaker device arranged in the insulation monitoring device. Furthermore, the invention relates to a method for performing an initial and/or repeated test of an insulation resistance in an unearthed IT power supply system and for monitoring the insulation resistance by means of an insulation monitoring device. For performing the initial and/or repeated test, the measuring circuit is interrupted by way of a manual switching act that activates a breaker device arranged in the insulation monitoring device. ## Claims ### Claim 1 An insulation monitoring device (IMD) that is installed between active conductors (L1, L2) of an IT power supply system (2) and a protective earth (PE) and forms a measuring circuit (8) with the unearthed IT power supply system (2) for monitoring an insulation resistance (RF), characterized by a breaker device (10) arranged in the insulation monitoring device (IMD) for interrupting the measuring circuit (8). ### Claim 2 (depends on 1) The insulation monitoring device (IMD) according to claim 1, characterized in that the breaker device (10) comprises a relay contact or an electronic semiconductor switching element as switching means. ### Claim 3 (depends on 2) The insulation monitoring device (IMD) according to claim 2, characterized in that the switching means of the breaker device (10) is configured to be redundant. ### Claim 4 (depends on 1, 2, 3) The insulation monitoring device (IMD) according to any of the claims 1 to 3, characterized by an input device (12) for manually entering a switching information that triggers the interruption and/or a closing of the measuring circuit (8) by the breaker device (10). ### Claim 5 (depends on 1, 2, 3, 4) The insulation monitoring device (IMD) according to any of the claims 1 to 4, characterized by an interface (14) for transmitting an external signal for the interruption and/or for the closing of the measuring circuit (8) by the breaker device (10). ### Claim 6 (depends on 1, 2, 3, 4, 5) The insulation monitoring device (IMD) according to any of the claims 1 to 5, characterized by an electrical energy storage unit (18). ### Claim 7 (depends on 6) The insulation monitoring device (IMD) according to claim 6, characterized in that the electrical energy storage unit (18) is implemented as a capacitor or as a battery. ### Claim 8 (depends on 1, 2, 3, 4, 5, 6, 7) The insulation monitoring device (IMD) according to any of the claims 1 to 7, characterized by a signal and control unit (16) that signals the interrupted state of the measuring circuit (8). ### Claim 9 (depends on 8) The insulation monitoring device (IMD) according to claim 8, characterized in that the signal and control unit (16) is embodied such that it causes the measuring circuit (8) to close automatically. ### Claim 10 A method for carrying out an initial and repeated test of an insulation resistance (RF) in an unearthed IT power supply system (2) and for monitoring the insulation resistance (RF) with an insulation monitoring device (IMD) that is installed between active conductors (L1, L2) of the IT power supply system (2) and a protective earth (PE), comprising the method steps of: carrying out the initial and/or repeated test, wherein a measuring circuit (8) formed by the insulation monitoring device (IMD) and the IT power supply system (2) is interrupted, and monitoring the insulation resistance (RF) by means of the insulation monitoring device (IMD) while the measuring circuit (8) is closed, characterized in that for performing the initial and/or repeated test, the measuring circuit (8) is interrupted by means of a manual switching act that activates a breaker device (10) arranged in the insulation monitoring device (IMD). ### Claim 11 (depends on 10) The method according to claim 10, characterized in that the manual switching act takes place in that a switching information is entered at the insulation monitoring device (IMD). ### Claim 12 (depends on 11) The method according to claim 11, characterized in that the manual switching act takes place remotely by way of a signal that is received via an interface (14) by the insulation monitoring device (IMD). ### Claim 13 (depends on 10, 11, 12) The method according to any of the claims 10 to 12, characterized in that the interrupted state of the measuring circuit (8) is signaled. ### Claim 14 (depends on 10, 11, 12, 13) The method according to any of the claims 10 to 13, characterized in that the measuring circuit (8) closes automatically.