The difference in measurement values can be attributed to the difference in calculation methods for normal mode and harmonic mode.

The voltage, current, and power in normal mode are displayed as the total of the measured values from all components (starting with the DC current component) in the bandwidth range. Therefore, even if there are signal components between the fundamental wave and the second order harmonic (interharmonic components exist), they are included in the total value that is displayed.

On the other hand, when measuring in harmonic mode, signal components between the fundamental wave component and 2nd order harmonic component are not included in the total values for voltage, current, and power. In other words, since the interharmonics are not included in the total value (fundamental wave + 2nd order + 3rd order...), basically the total value in harmonic mode is slightly smaller than that of normal mode.

Please see the attached images highlighting the differences between normal mode and harmonic mode.

- Power and Harmonic (THD) Measurements with Independent Range Controls
- Efficiency measurements of AC/DC or DC/AC Inverters & Motors

With 0.02% accuracy and 1MHz bandwidth, the WT3000 delivers where the highest precision measurements are required. It is the industry standard for R&D work on inverters, motor drives, lighting systems and electronic ballasts, UPS systems, aircraft power, transformer testing, and other power conversion devices.

The PZ4000 is designed for High Frequency Power Measurements as well as Transient Power Measurements. Its real-time acquisition system can perform cycle-by-cycle power measurements. One to Four input elements offer Basic Power Accuracy of 0.2% with 2 MHz Bandwidth and 5MS/sec digitizing rates.

The High-end WT1600 is designed for a wide range of applications, from energy-saving to large load applications. The WT1600 has a six element input capability to provide maximum flexibility, and Basic Power Accuracy of 0.1% with 1 MHz Bandwidth.

The WT1800 Power Analyzer offers maximum flexibility with up to six wattmeter elements, high bandwidths, simultaneous high speed digitizing, and wide voltage and current ranges. Although this model is still available, the newer WT1800E offers higher accuracy.

The WT2000 digital powermeter series has been designed with emphasis on basic performance (bandwidth, accuracy, response speed, and noise immunity) from the viewpoint of measurement of electrical quantities. The broad range of functions of these power analyzers enable them to be used in various fields of applications.

Measure characteristics of devices that generate, transform or consume electricity. Also called power meters or wattmeters, these devices measure parameters such as true power (watts), power factor, harmonics, and efficiency.

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