Precision power analyser offers innovative measurement functions

The Yokogawa WT1800 precision power analyser is the latest addition to the company's highly successful range of digital power measuring instruments.

Replacing the WT1600, an industry standard for many years, the WT1800 offers innovative measurement functions which benefit the engineer with electrical power and efficiency measurements in a range of industries from inverter and drive design to alternative energy systems.

"Both the traditional power generation and distribution sectors and the emerging alternative energy markets are placing increased emphasis on energy saving and efficiency, while manufacturers of equipment from industrial drives to washing machines are also looking at optimising energy performance with the resultant economic and environmental benefits", says Terry Marrinan, Sales & Marketing Director for Europe & Africa with Yokogawa's Test & Measurement Business Unit: "Yokogawa's history of market leadership and innovation in the power measurement sector puts us in a strong position to support customers in these sectors, and the WT1800 is a key product in this process."

The WT1800 is capable of performing up to six power input measurements, which makes it possible to perform efficiency tests between the input and output of products such as inverters. With its high-resolution 8.4-inch XGA display, the instrument is simple to set up and display up to 12 different pages of measurement items in formats such as numeric, waveforms and trends. A vector display is available for voltage and current phase analysis.

Many of today's power conversion circuits use energy-saving switching techniques which can cause highly distorted voltage or current waveforms with high harmonic content. To measure these waveforms accurately, the WT1800 uses high-resolution 16-bit analogue-digital converters with a digitising rate of 2 MS/s (megasamples per second).

The WT1800 has a power measurement bandwidth from DC and 0.1 Hz to 1 MHz. Basic power measurement accuracy is 0.1% of Reading plus 0.05% of range.

For electric motor testing applications, the WT1800 offers a unique and powerful motor evaluation function which offers, in a single unit, measurements of all the relevant electrical power parameters along with rotational speed, torque, mechanical power, synchronous speed, slip, motor efficiency and total system efficiency.

In addition, A-phase, B-phase and Z-phase input terminals have been added for advanced motor analysis. These signals make it possible to detect the rotational direction of the motor as well as the electrical angle measured using the Z-phase signal.

A new programmable digital filter function enhances the capability to remove unnecessary harmonic components and noise superimposed on signals such as from an inverter or variable-speed motor drive. This filter can be set independently for each input element, from 100 Hz to 100 kHz in 100 Hz increments. An analogue filter is also provided for 300 kHz and 1 MHz filtering on each input element.

Harmonic analysis can be carried out up to the 500th order from a 50 or 60 Hz fundamental frequency. This facility is especially important for measurements on new power conversion and power electronics devices.

An industry first dual harmonic measurement function makes it possible to simultaneously measure the harmonic content and perform harmonic analysis on two different sources, such as the input and output of an inverter, variable-speed motor drive, lighting ballast, uninterruptible power supply or similar devices. The normal power parameters and harmonic data are measured simultaneously, providing for faster and more accurate power analysis.

For photovoltaic power generation applications, a maximum peak power tracking measurement is available to maximise the harvested power generated by photovoltaic cells. To accomplish this, the WT1800 is capable of measuring voltage, current and power peak values and calculating the derived parameters.

A power integration function is also available which can be used to measure the amount of power sold or purchased in grid interconnection applications. The WT1800 features Yokogawa's average active power function, making it possible to measure power consumption under conditions where the power fluctuates greatly.

For the first time in the high-precision power analyser industry, an event trigger function is incorporated to capture only a particular event. A trigger can be set for measured values that fall out of a pre-selected range, and the WT1800 will only store, print or save data that meets the trigger condition.

All the latest communication interface ports such as Ethernet, USB and GPIB are included in the WT1800. Support for USB removable storage media is also provided.