Abstract: A portable device for field testing watthour meters including a socket with one or more connectors configured to engage a watthour meter blade is disclosed. The connectors may include a pair of wire forms so oriented that the connector can connect to a watthour meter blade oriented in either of two orientations 90° apart from each other by resiliently deflecting portions of the wire forms. The connectors may include a jaw socket cup, a torsion clip in the jaw socket cup for contacting a watthour meter blade when the watthour meter blade is inserted into the jaw socket cup. The torsion clip includes a first surface and a pair of facing surfaces connected to, and extending away from, the first surface that define a channel sized to receive the watthour meter blade.

Abstract: A method and apparatus for testing a transformer. A controller generates a switching signal and supplies the switching signal to a solid state switch in circuit with a test load of known magnitude, switching the solid state switch to place the test load in circuit with the transformer. A signal through or across the transformer is then measured. Methods and apparatus for testing a transformer comprise the controller and solid state switch placing a series of test loads of different known magnitudes in circuit with the transformer from the lowest magnitude to the highest, from the highest to the lowest, or both. Additionally, a test load array comprises a plurality of power resistors, a heat sink for accommodating the plurality of power resistors, and a material providing electrical insulation of the power resistors from the heat sink and thermal conductivity between the power resistors and the heat sink.

Abstract: A universal meter socket for portable test equipment has low insertion and extraction forces. The universal meter socket is durable and light in weight, providing a long service life. The universal meter socket contains field-cleanable terminals with replaceable wear components. The universal meter socket also optimizes short current paths for the high current section of the meter, further reducing equipment weight by reducing wire weight and volt-ampere (hereinafter sometimes VA) drive requirements for test equipment. The universal meter socket complies with ANSI C12.7-2005 REQUIREMENTS FOR WATTHOUR METER SOCKETS. The universal meter socket is generally intended for use with electricity meters that comply with ANSI C12 requirements.

Abstract: A method and apparatus for testing a transformer. A controller generates a switching signal and supplies the switching signal to a solid state switch in circuit with a test load of known magnitude, switching the solid state switch to place the test load in circuit with the transformer. A signal through or across the transformer is then measured. Methods and apparatus for testing a transformer comprise the controller and solid state switch placing a series of test loads of different known magnitudes in circuit with the transformer from the lowest magnitude to the highest, from the highest to the lowest, or both. Additionally, a test load array comprises a plurality of power resistors, a heat sink for accommodating the plurality of power resistors, and a material providing electrical insulation of the power resistors from the heat sink and thermal conductivity between the power resistors and the heat sink.

Abstract: A transformer includes at least two magnetically coupled cores with a common axis. The cores have cross sectional configurations transverse to the common axis which are not rectangular. An exciting voltage is to be applied across a first winding provided on one of the cores. A second winding provided on one of the cores includes first and second terminals across which a voltage is to be induced in response to the exciting voltage. A first device provides a relatively higher impedance between the first and second terminals of the second winding. The first device is coupled between the first and second terminals. Third, fourth and fifth windings have respective first and second terminals. The third and fourth windings are wound on one of the cores with a first polarity. The fifth winding is wound on one of the cores with a second polarity opposite to the first polarity.

Abstract: A transformer includes a first winding and a second winding coupled to the first winding through a magnetic circuit so that current through the first winding induces a voltage across the second winding. The first winding includes n separate shield portions, where n is an integer. Each of the n shield portions shields only a corresponding portion of the first winding. Each of the n shield portions is electrically coupled to the adjacent shield portion(s) substantially only through its coupling to the first winding, the first winding, and the other(s) of the adjacent shield portion's (s') coupling(s) to the first winding.

Abstract: A transformer includes at least two magnetically coupled cores with a common axis. The cores have cross sectional configurations transverse to the common axis which are not rectangular. An exciting voltage is to be applied across a first winding provided on one of the cores. A second winding provided on one of the cores includes first and second terminals across which a voltage is to be induced in response to the exciting voltage. A first device provides a relatively higher impedance between the first and second terminals of the second winding. The first device is coupled between the first and second terminals. Third, fourth and fifth windings have respective first and second terminals. The third and fourth windings are wound on one of the cores with a first polarity. The fifth winding is wound on one of the cores with a second polarity opposite to the first polarity.

Abstract: A transformer includes taps by which electrical contact can be made to winding sections of the transformer at locations along its length between its end terminals. A first switch permits contact to be made selectively to a selected one of the taps. An amplifier has an inverting input terminal, a non-inverting input terminal and an output terminal. The output terminal of the amplifier is coupled to the first switch so that selectively making contact with one of the taps couples the selected tap to the output terminal of the amplifier.

Abstract: A method and apparatus for analog-to-digital (A/D) converting an input signal having a first polarity include providing an integrator including a capacitance coupled to an input port of an amplifier, coupling an A/D converter to an output port of the amplifier, changing the amount of charge stored in the capacitance by coupling the input signal and a reference source having a second and opposite polarity to the capacitance, and controlling an A/D conversion cycle of the A/D converter to simultaneously charge and discharge the capacitance with the input signal and the reference source prior to each A/D conversion cycle.

Abstract: A transformer having a primary winding and a secondary winding across which load is coupled is compensated. A third winding is provided on the transformer. A first output terminal of an amplifier is coupled to a first terminal of the primary winding. A first terminal of the third winding is coupled to the second terminal of the primary winding. A second terminal of the third winding is coupled to an input terminal of the amplifier.

Abstract: A system for increasing the voltage handling capacity of an amplifier circuit coupled to a transformer output comprises a transformer secondary winding divided into n sub secondary windings, where n is an integer. A first terminal of a first of the sub secondary windings is coupled to a reference potential. n amplifiers, numbered sequentially 1.ltoreq.m.ltoreq.n as they appear in the amplification circuit with an output terminal of the nth amplifier comprising an output terminal of the amplification circuit, each have an input terminal and an output terminal. An input terminal of the first amplifier is coupled to a second terminal of the first sub secondary winding. An output terminal of each of the n amplifiers is coupled to a first terminal of the next adjacent higher numbered sub secondary winding, except for the nth amplifier, the output of which comprises the output of the amplifier circuit.