A method (400) of determining equivalent circuit parameters of a three phase induction motor is provided. The method (400) comprises applying (410) a current to a stator winding (362) of an induction motor (360), and varying (420) a voltage applied to the stator winding to regulate the applied current to be a constant current. Application of the current is terminated (430) when the applied voltage has reached a constant voltage. The equivalent circuit parameters are determined (440) from the value of the constant current, the values of the applied voltage, and a time period until the applied voltage attains the constant voltage. The method may provide values for a resistance (210) of the stator winding, a resistance (250) of a rotor winding (364), a magnetizing inductance (230), and a total inductance leakage value (220, 240) for the stator winding and the rotor winding.

A resistance measuring device includes: a first jig; a plurality of first contacts; a second jig; a plurality of second contacts; a resistance measuring unit that supplies a current between a first contact and a second contact, which correspond to each other, detects a voltage between a first contact and a second contact, and calculates a resistance value of an object to be measured based on a relationship between a value of the supplied current and a value of the detected voltage; first wirings connecting the resistance measuring unit and each of the first contacts, for the first contacts, respectively; and second wirings connecting the resistance measuring unit and each of the second contacts while passing from the resistance measuring unit through the first jig, for the second contacts, respectively.

A resistance measuring device includes: a first jig; a plurality of first contacts; a second jig; a plurality of second contacts; a resistance measuring unit that supplies a current between a first contact and a second contact, which correspond to each other, detects a voltage between a first contact and a second contact, and calculates a resistance value of an object to be measured based on a relationship between a value of the supplied current and a value of the detected voltage; first wirings connecting the resistance measuring unit and each of the first contacts, for the first contacts, respectively; and second wirings connecting the resistance measuring unit and each of the second contacts while passing from the resistance measuring unit through the first jig, for the second contacts, respectively.

A system and method (referred to as a method) to fabricate sensors and electronic circuits. The method prints a first thin-film having an electronic conductivity of about less than a millionth of a Siemens per meter and a permalloy directly onto the first thin-film. The permalloy has a magnetic permeability greater than a predetermined level and has a thickness within a range of about 1 to 20 microns. The system prints a second thin-film directly onto the permalloy to encapsulate the permalloy onto the first thin-film and prints conductive traces directly onto the surfaces of the first-thin-film, the permalloy, and the second thin-film. In some applications, a sensor is packaged in an additively manufactured three-dimensional cylindrical shape that can be mounted on or is a unitary part of a current carrying conductor without incising, sharing, or severing (e.g., cutting) the current carrying conductor or its insulation.

A system and method (referred to as a method) to fabricate sensors and electronic circuits. The method prints a first thin-film having an electronic conductivity of about less than a millionth of a Siemens per meter and a permalloy directly onto the first thin-film. The permalloy has a magnetic permeability greater than a predetermined level and has a thickness within a range of about 1 to 20 microns. The system prints a second thin-film directly onto the permalloy to encapsulate the permalloy onto the first thin-film and prints conductive traces directly onto the surfaces of the first-thin-film, the permalloy, and the second thin-film. In some applications, a sensor is packaged in an additively manufactured three-dimensional cylindrical shape that can be mounted on or is a unitary part of a current carrying conductor without incising, sharing, or severing (e.g., cutting) the current carrying conductor or its insulation.

Electrical current flow in a ball grid array (BGA) package can be measured by an apparatus including an integrated circuit (IC) electrically connected to the BGA package. Solder balls connect the BGA package to a printed circuit board (PCB). A current sense mesh can be placed between adjacent solder balls and is attached to the upper surface of the PCB. The solder balls are electrically connected to supply current from the PCB through the BGA package to the IC. A MUX/Sequencer can sequentially connect wires of the current sense mesh to an amplifier. The amplifier can amplify a voltage induced on the current sense mesh by current flow into the BGA package. A sensing analog-to-digital converter (ADC) is electrically connected to convert a voltage at the output of the amplifier into digital output signals.

A quantum-based sensor includes a hollow electromagnetic (EM) waveguide having non-metallic layers and external metallic layers. The hollow EM waveguide encloses a gas having a pressure that is less than a threshold pressure, and all interior surfaces of the hollow EM waveguide in contact with the gas are non-metallic.

A quantum-based sensor includes a hollow electromagnetic (EM) waveguide having non-metallic layers and external metallic layers. The hollow EM waveguide encloses a gas having a pressure that is less than a threshold pressure, and all interior surfaces of the hollow EM waveguide in contact with the gas are non-metallic.

An electrical device includes a sensor unit. The electrical device includes a first surface that is provided with a depression, and a second surface that is provided with a lug, the second surface being orthogonal to the first surface. The sensor unit includes a contact surface that is provided with a projection fitted to the depression, the contact surface being in contact with the first surface, and a hook that is engaged with the lug, the hook extending along the second surface, and the hook being elastically deformable in a direction normal to the second surface.

An electrical device includes a sensor unit. The electrical device includes a first surface that is provided with a depression, and a second surface that is provided with a lug, the second surface being orthogonal to the first surface. The sensor unit includes a contact surface that is provided with a projection fitted to the depression, the contact surface being in contact with the first surface, and a hook that is engaged with the lug, the hook extending along the second surface, and the hook being elastically deformable in a direction normal to the second surface.