If you want to really see what’s happening on power lines, you need an instrument that can generate a phasor diagram of the line voltages and currents. An instrument able to do that and much more recently became available from Keysight Technologies. Engineers can use the firm’s IntegraVision PA2203A four-channel power analyzer to observe three-phase power consumption under dynamic conditions on a built-in 12.1-in. capacitive touchscreen.
The instrument provides a numerical read-out of power factor, Var, VA, power draw in watts, and several other factors for three-phase lines. It does so with a 0.05% basic accuracy and 16-bit resolution. Additionally, it lets users visualize transients, in-rush currents and state changes with a 5-M sps digitizer that captures voltage, current and power in real time with 2.5-MHz bandwidth.
The IntegraVision PA2203A includes external sensor inputs and 2-Arms and 50-Arms direct current inputs. The external sensor input supports current probes and transducers up to 10-V full scale. Inputs are isolated up to 1 kVrms (Cat II) and an integrated data logger records for up to a year for offline analysis.
The typical application for the Keysight analyzer is in identifying incremental improvements in highly efficient power converters. The instrument is also good at aiding in the visualization of transients, in-rush currents and state changes thanks to its high-speed digitizer.
The instrument can also double as a truth-detector when gauging claims of energy efficiency. For example, vendors of “black box” energy efficiency equipment sometimes run demonstrations of their “solutions” on lightly loaded motors. The black box frequently consists of a capacitor effecting a power-factor correction. Switching the black box into the circuit reduces a simple readout of amps dissipated in the load. Examining the input in terms of a phasor diagram, however, can give a graphic depiction that clarifies the situation: The magnitude of load current drops, but the overall power into the circuit generally stays about the same.
Other features of the new instrument include an on-screen wizard for step-by-step visual guidance to set up complex three-phase wiring, and the choice of a delta (triangle) connection that wires between phases, or a wye (star) connection that wires from a phase wire to a common neutral point.
Filed Under: Power Electronic Tips, Power supplies