Accuracy boosted in power-meter upgrade

September 02, 2015 // By Graham Prophet
Yokogawa has updated its power meter range with the WT300E Series, that has improved accuracy, new measurement functionality and added connectivity including Modbus/TCP capability to aid integration into production environments.

This WT300E Series has a basic power accuracy of ±0.15% at 50/60 Hz on all measurement ranges - the highest level of accuracy available in any compact power meter – along with a bandwidth of DC and 0.1 Hz to 100 kHz. The influence of power factor is also greatly reduced: at low power factor the accuracy is twice that of the previous models (±0.1% of apparent power S).

The WT300E series covers input currents from a few milliamperes up to 40A RMS, making it equally suitable for measuring low currents in standby power testing to the high currents encountered in induction cookers. It can also measure waveforms with both AC and DC content.

The Series comprises four models: the WT310E single phase (including extremely low-current measurement capability down to 50 µA); WT310EH single phase high current; WT332E two-element; and WT333E three-element.

WT310E suits standby power measurements, Energy Star, SPECpower and IEC62301/EN50564 testing as well as battery-charger and other low level power measurements; WT310EH is a single-phase high-current version with current ranges from 1A to 40A RMS. The bandwidth on this model is DC and 0.1 Hz to 20 kHz. The WT332E is a two-element meter for use on split-phase and three-phase/three-wire circuits. The WT333E is a three element meter for use on three-phase/three-wire or three-phase/four-wire circuits. These models have current ranges of 0.5A to 20A RMS, with low-current measurements down to 5 mA. All models have voltage ranges from 15 to 600 V RMS, and low voltage measurement capability to 150 mV.

The units have enhanced low-frequency measurement capability of 0.1 Hz in addition to the upper bandwidth limit of 100 kHz. An optional harmonic analysis function is available which provides simultaneous measurement of both the normal power parameters and harmonic data for faster and more accurate power analysis. Harmonic analysis and total harmonic distortion calculations can be made up to the 50th order from a 50 or 60