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.

The present disclosure relates to circuitry for driving a load. The circuitry comprises: primary driver circuitry coupled to a primary signal path and operable to drive the load with a playback signal in a first mode of operation of the circuitry, wherein a playback signal comprises a signal that drives the load to generate a desired output; auxiliary driver circuitry coupled to an auxiliary signal path; an auxiliary current sense resistor in the auxiliary signal path; and current detection circuitry coupled to the auxiliary current sense resistor and configured to generate a signal indicative of a current through the load. One of the primary driver circuitry and the auxiliary driver circuitry is operable to drive the load with a pilot signal in a second mode of operation of the circuitry, wherein a pilot signal comprises a signal having a predefined frequency or frequency content and a predefined magnitude.

Controller of power storage pack performs communication for authentication with controller of an electric moving body according to the pattern of a current flowing through a power line in a state where power storage pack is mounted to electric moving body. Controller of power storage pack measures contact resistance between power storage pack and the electric moving body based on voltage of the power line on power storage pack side, voltage of the power line on the electric moving body side received from controller of the electric moving body, and current when communication for authentication is performed according to the pattern of a current flowing through the power line.

Controller of power storage pack performs communication for authentication with controller of an electric moving body according to the pattern of a current flowing through a power line in a state where power storage pack is mounted to electric moving body. Controller of power storage pack measures contact resistance between power storage pack and the electric moving body based on voltage of the power line on power storage pack side, voltage of the power line on the electric moving body side received from controller of the electric moving body, and current when communication for authentication is performed according to the pattern of a current flowing through the power line.

The invention relates to a mobile electric energy supply device, comprising at least one energy supply connector for drawing energy from the energy supply device, a ground grounding device adapted to cooperate with a ground of the installation site of the energy supply device to provide grounding for the energy supply device, and a touch safety monitoring device adapted to monitor at least one touch point disposed on or electrically connected to the energy supply device for touch safety.

The invention relates to a mobile electric energy supply device, comprising at least one energy supply connector for drawing energy from the energy supply device, a ground grounding device adapted to cooperate with a ground of the installation site of the energy supply device to provide grounding for the energy supply device, and a touch safety monitoring device adapted to monitor at least one touch point disposed on or electrically connected to the energy supply device for touch safety.

A method determines an insulation resistance of the high-voltage network in an electric or hybrid vehicle, in which a controllable continuous voltage source connected to the body and to a single first terminal of a high-voltage battery of the vehicle is provided, a first resistor being connected in series to the source between the single first terminal and the body and a second resistor being connected in series between the first resistor and the source, consecutive voltage setpoint values are applied between the body and the single first terminal, a measurement signal of the voltage at the terminals of the second resistor is acquired for each setpoint value, adaptive filtering of the signal is carried out and an estimate made, in a recursive manner, of a vector of the filter transfer function coefficients, providing an update of the filtering coefficients, the insulation resistance being determined based on the estimate.

A method determines an insulation resistance of the high-voltage network in an electric or hybrid vehicle, in which a controllable continuous voltage source connected to the body and to a single first terminal of a high-voltage battery of the vehicle is provided, a first resistor being connected in series to the source between the single first terminal and the body and a second resistor being connected in series between the first resistor and the source, consecutive voltage setpoint values are applied between the body and the single first terminal, a measurement signal of the voltage at the terminals of the second resistor is acquired for each setpoint value, adaptive filtering of the signal is carried out and an estimate made, in a recursive manner, of a vector of the filter transfer function coefficients, providing an update of the filtering coefficients, the insulation resistance being determined based on the estimate.

The invention relates to a method for operating a power tool, according to which a measuring device determines a winding resistance (R.sub.S) of a winding of an electric motor of the power tool. A test signal source applies a test signal (i.sub.p) to the winding during operation of the electric motor, a measuring unit records at least one measured value (U.sub.d, i.sub.d) as a reaction of the winding to the test signal (i.sub.p), and a control device determines the winding resistance (R.sub.S) while taking into consideration the measured value (U.sub.d, i.sub.d).

The invention relates to a method for operating a power tool, according to which a measuring device determines a winding resistance (R.sub.S) of a winding of an electric motor of the power tool. A test signal source applies a test signal (i.sub.p) to the winding during operation of the electric motor, a measuring unit records at least one measured value (U.sub.d, i.sub.d) as a reaction of the winding to the test signal (i.sub.p), and a control device determines the winding resistance (R.sub.S) while taking into consideration the measured value (U.sub.d, i.sub.d).