A drawing apparatus according to the embodiment includes a chamber configured to house a processing target; a drawing part configured to draw a predetermined pattern on the processing target with a charged particle beam; a resistance measuring part configured to measure a resistance value of the processing target via a grounding member grounding the processing target in the chamber; a receiver configured to receive earthquake information; a controller configured to stop a drawing process in the chamber when the receiver receives the earthquake information; and an arithmetic processor configured to determine whether the processing target is grounded on a basis of the resistance value from the resistance measuring part, wherein the controller resumes the drawing process when the arithmetic processor determines that the processing target is grounded after the drawing process is stopped.

A drawing apparatus according to the embodiment includes a chamber configured to house a processing target; a drawing part configured to draw a predetermined pattern on the processing target with a charged particle beam; a resistance measuring part configured to measure a resistance value of the processing target via a grounding member grounding the processing target in the chamber; a receiver configured to receive earthquake information; a controller configured to stop a drawing process in the chamber when the receiver receives the earthquake information; and an arithmetic processor configured to determine whether the processing target is grounded on a basis of the resistance value from the resistance measuring part, wherein the controller resumes the drawing process when the arithmetic processor determines that the processing target is grounded after the drawing process is stopped.

The invention relates to an electric circuit arrangement (2) for standard insulation monitoring with emergency shut-down for an ungrounded power supply system (4) upon detection of a ground fault, having a standard insulation monitoring device (10) which is coupled to an active conductor (L1, L2, L3) of the power supply system (4) on the network side via a coupling branch (12) each or to a neutral point (S) of the power supply system (4) via a coupling branch (12) and is connected to ground (PE) on the ground side via a ground connection branch (14). The electric circuit arrangement (2) comprises an AC/DC sensitive measuring current transformer (20) which detects a fault current on the network side at the active conductors (L1, L2, L3) in the coupling branches (12) or at the neutral point (S) in the coupling branch (12) or on the ground side in the ground connection branch (14) of the insulation monitoring device (10); an evaluator (30) for evaluating the fault current with regard to a fault current threshold being exceeded; and a trip device (40) for shutting down the power supply system (4).

A coupling circuit (20) with switching function for coupling an insulation monitoring device (6, 6a, 6b) to an unearthed power supply system (2, 2a, 2b), consisting of a coupling module (22) or a plurality of identical coupling modules (22) connected in series, wherein the coupling module (22) has at least one switch unit (25), which comprises a coupling impedance (26), a switch (24), arranged in series to the coupling impedance (26), for mains disconnection and a control circuit (28) for controlling the switch (24), and also exactly one transformer (30) for voltage supply and for potential separation.

A coupling circuit (20) with switching function for coupling an insulation monitoring device (6, 6a, 6b) to an unearthed power supply system (2, 2a, 2b), consisting of a coupling module (22) or a plurality of identical coupling modules (22) connected in series, wherein the coupling module (22) has at least one switch unit (25), which comprises a coupling impedance (26), a switch (24), arranged in series to the coupling impedance (26), for mains disconnection and a control circuit (28) for controlling the switch (24), and also exactly one transformer (30) for voltage supply and for potential separation.

The invention relates to a method and a photovoltaic inverter (2) for determining the insulation resistance (R.sub.iso) of a photovoltaic system (1) relative to ground (PE). According to the invention, the voltage required for the measurement can be provided by the intermediate circuit (6) in the form of the intermediate circuit voltage (U.sub.Zk), and the measuring device (13) is designed to actuate an input short-circuit switch (S.sub.Boost) for short-circuiting the DC input (3) with the AC disconnector (8) open, as a result of which the intermediate circuit voltage (U.sub.Zk) can be applied to the DC input (3) in the reverse direction, and the measuring device (13) is configured to record measured voltages (U.sub.M1, U.sub.M2) with the switch (S.sub.iso) of the voltage divider (14) open and closed, and to determine the insulation resistance (R.sub.iso) from the measured values of the two measured voltages (U.sub.M1, U.sub.M2) recorded with the switch (S.sub.iso) of the voltage divider (14) open and closed.

It is described an electrical installation measuring system comprising a control and measuring device configured to be installed on an electrical panel of an electrical installation and perform at least one measure of an electrical parameter of the electrical installation depending on an electrical load connected to the electrical installation and transmit command signals along a telecommunication link. The system further comprises a variable load device connectable to the electrical installation and configured to: receive the command signals from the telecommunication link; and assume a plurality of load configurations according to the command signals.

Loop resistance is measured in a live-earth conductor loop comprising a residual current device powered by an alternating current mains supply. A measurement circuit having a low-pass filter characteristic arranged to substantially remove signal components at the frequency of the alternating current mains supply is used to measure, in a first period, a voltage across live and earth conductors of the live-earth conductor loop to determine a first voltage. A current application circuit is used to apply a unipolar test current having a magnitude below a trip current value of the residual current device for a second period and the measurement circuit is used to measure a second voltage between the live and earth conductors. Based on a difference in test current between the first and second periods and a difference in voltage between the first voltage and the second voltage, the resistance of the live-earth conductor loop is calculated.

Loop resistance is measured in a live-earth conductor loop comprising a residual current device powered by an alternating current mains supply. A measurement circuit having a low-pass filter characteristic arranged to substantially remove signal components at the frequency of the alternating current mains supply is used to measure, in a first period, a voltage across live and earth conductors of the live-earth conductor loop to determine a first voltage. A current application circuit is used to apply a unipolar test current having a magnitude below a trip current value of the residual current device for a second period and the measurement circuit is used to measure a second voltage between the live and earth conductors. Based on a difference in test current between the first and second periods and a difference in voltage between the first voltage and the second voltage, the resistance of the live-earth conductor loop is calculated.

A method and a measuring device for detecting a leakage current in an ungrounded, single-phase alternating-current power supply system. A variable test resistance is switched between one of the outer conductors and ground and starting from a minimally admissible test-resistance value, at least one of three support test-resistance values is determined as support locations. In an equivalent circuit of the modeled alternating-current power supply system, an equations system is set up for describing the dependency of currents and voltages. An extrapolation on the test-resistance value zero leads to a calculated test current which corresponds to the leakage current to be detected. Consequently, a ground fault situation may be simulated without actually causing a dangerous ground fault.