The present disclosure relates to a grounding monitoring device, method, system and computer readable storage medium, which relates to the field of coal mine safety. The device includes: a measurement power source for supplying power to the grounding monitoring device; a resistance measurement device connected between the measurement power source and a grounding electrode, the resistance measurement device, the measurement power source and the grounding electrode forming a current detection circuit via the ground, wherein a resistance of a grounding resistor is determined according to a current flowing through the grounding electrode in the current detection circuit to determine a monitoring result.

An inspection tool and associated methods for testing physical and electrical properties of a perforating gun segment, wherein the perforating gun segment is received in a perforating gun segment holder positioned between a first connecting portion and second connecting portion. The inspection tool may be for establishing, testing, and confirming the position of an internal gun assembly and the electrical properties of certain electrical connections of the perforating gun segment. Electrical testing contacts and/or distance sensors may be positioned on one of the first connecting portion and the second connecting portion for measuring the position of the internal gun assembly and the electrical properties. In an aspect, the inspection tool may include a piston for pushing, via the first connecting portion, the internal gun assembly to a predetermined position, and establishing electrical connections to test the electrical properties of the perforating gun segment.

A method for detecting an insulation damage location in a reflux rail of a subway/coal mine and a transition resistance thereof includes the following steps: connecting a reflux rail to a negative electrode of a substation, selecting a location at a connecting point as a reference location, and mounting a potential detection apparatus at the reference location; mounting a travel distance detection apparatus and a traction current detection apparatus on a locomotive, traveling, by the locomotive, to the substation along the reflux rail, where the three detection apparatuses send respectively recorded data to a control unit; and determining, by the control unit, a potential jump from received potential data and a corresponding jump time, and determining a running distance of the locomotive at a jump moment and a total running length of the locomotive, so as to determine a ground insulation damage location.

A method for detecting an insulation damage location in a reflux rail of a subway/coal mine and a transition resistance thereof includes the following steps: connecting a reflux rail to a negative electrode of a substation, selecting a location at a connecting point as a reference location, and mounting a potential detection apparatus at the reference location; mounting a travel distance detection apparatus and a traction current detection apparatus on a locomotive, traveling, by the locomotive, to the substation along the reflux rail, where the three detection apparatuses send respectively recorded data to a control unit; and determining, by the control unit, a potential jump from received potential data and a corresponding jump time, and determining a running distance of the locomotive at a jump moment and a total running length of the locomotive, so as to determine a ground insulation damage location.

A connection quality system can include a resistance test module, a first line connected to the resistance test module and configured to connect to a wire connection assembly past one or more physical connections of the wire connection assembly, and a second line connected to the resistance test module and configured to connect to the wire connection assembly directly or indirectly on an opposite side of the one or more physical connections of the wire connection assembly such that the first line and the second line are in electrical communication through the wire connection assembly. The resistance test module can be configured to determine if the one or more physical connections are degraded or broken based on a resistance of the wire connection assembly.

Circuits and methods are disclosed for determining a ground path impedance difference in a vehicle having master and slave control. An example circuit for detecting a difference in ground path impedance in a vehicle includes a master ground terminal and a slave ground terminal. The circuit also includes a first shunt resistor electrically coupled between the master ground terminal and a common internal ground, and a second shunt resistor electrically coupled between the slave ground terminal and the common internal ground. The circuit further includes a bi-directional current sense amplifier having as inputs the master ground terminal and the slave ground terminal.

A motor driving device includes: a converter unit having a capacitor; a plurality of inverter units having a plurality of semiconductor switching elements and configured to convert a capacitor voltage across the capacitor into an AC voltage to drive a plurality of motors; a second switch configured to connect the negative-side terminal of the capacitor to ground; a first detector configured to detect a ground-referenced voltage; and a second detector configured to detect the capacitor voltage. The motor driving device controls the semiconductor switching elements to establish a measurement state for enabling measuring of the insulation resistance of a measurement target motor, estimates a convergence value of the ground-referenced voltage based on multiple measurements of the ground-referenced voltage detected by the first detector, and then calculates the insulation resistance based on the estimated convergence value and the capacitor voltage.

A vehicle includes an Alternating Current (AC) source, a receptacle, and a switch. The AC source has a line and neutral potential. The receptacle is carried by a body of the vehicle and includes line, neutral, and ground conductors, and a ground fault interrupter (GFI) circuit. The switch is coupled between the AC source and the GFI circuit configured to selectively short the neutral and ground conductors.

A vehicle includes an Alternating Current (AC) source, a receptacle, and a switch. The AC source has a line and neutral potential. The receptacle is carried by a body of the vehicle and includes line, neutral, and ground conductors, and a ground fault interrupter (GFI) circuit. The switch is coupled between the AC source and the GFI circuit configured to selectively short the neutral and ground conductors.

The present disclosure provides a method for characterizing ohmic contact electrode performance of a semiconductor device. The method comprises: preparing two sets of testing patterns on a semiconductor device; testing resistance values of the two sets of testing patterns respectively; calculating a sheet resistance of an ohmic contact area according to the obtained resistance values; and evaluating the ohmic contact electrode performance of the semiconductor device according to the sheet resistance of the ohmic contact electrode.