Abstract: An apparatus and method for calibrating three-phase voltage spike waveforms used in testing three-phase electrical devices. The apparatus includes a circuit having a plurality of phase voltage lines and a ground line. Phase voltage outputs and a ground output are provided for connection to a device under test. A selection circuit selects one of the phase voltage lines and provides a synchronization voltage signal based on the other lines. A voltage spike generator is joined to the selection circuit for generating a voltage spike waveform synchronized with the voltage signal. Additional circuitry is joined to the voltage spike generator, the phase voltage lines and the outputs which applies the voltage spike waveform across the selected phase voltage line and the ground line.

Abstract: An apparatus and method for calibrating single phase voltage spikes used in testing single phase electrical equipment. Capacitance is selected from a capacitor network in order to adjust the single phase voltage spike so as to produce a predetermined voltage spike waveform having particular waveform characteristics that are required to perform survivability and compatibility tests.

Abstract: An apparatus and method are used to determine equivalent individual phase voltages and phase currents from an alternating delta power source and load configuration. A delta-wye input transformer and a wye-delta output transformer are interconnected between the delta power source and the delta power load. Each phase of the delta power source is effectively connected across a corresponding wye configured coil. The delta-wye input transformer and the wye-delta output transformer are electrically connected to each other in a manner thereby providing three conductors through which the individual phase currents through the wye coils may be directly measured. The phase voltages are preferably measured across the wye coils of either the input transformer or the output transformer not intermixed.

Abstract: An apparatus to provide spike conduction and power supply isolation that is effective for a 60 Hz power supply operating frequency. The power frequency blocking circuit is practically implemented for a 60 Hz power supply operating frequency. The power frequency blocking circuit provides an equivalent impedance of 100 ohms at the 60 Hz operating frequency, and the power frequency blocking circuit equivalent impedance is on the order of 1-2 ohms at frequencies above 1000 Hz where spike conduction is required. The power frequency blocking circuit is placed between each power supply terminal and ground. The circuit is comprised of a parallel combination resistor and capacitor.