Analyser runs four power measurements at once

A new precision power analyser combines an exceptionally high accuracy with a wide frequency range, even for power measurements.

Yokogawa will feature a new precision power analyser at PCIM 2005, which combines an exceptionally high accuracy (+/-0.02% of reading +0.04% of range) with a wide frequency range (DC, 0.1Hz to 1MHz), even for power measurements.

The new WT3000 can carry out up to four power measurements simultaneously, is easy to operate with direct keys, offers a variety of display formats on an 8.4in colour TFT, and includes powerful integrator functions as standard plus a wide range of options to enhance application-specific measurements.

Two versions of the WT3000 are available: the standard model, which is ideally suited to high-accuracy measurements of the input/output efficiency of inverters; and a dedicated motor version, which incorporates facilities for measuring torque and speed and converting measurements into mechanical parameters, with a data update speed from 50ms to 20s.

Measurements can be made over seven current ranges from 0.5 to 30A RMS and eight voltage ranges from 15 to 1000V RMS.

Guaranteed accuracy for AC voltage, current and power is between 1 and 130% of input range.

The continuous maximum common-mode voltage of 1000V RMS at 50/60Hz enables precision power measurements in the evaluation of inverter and motor efficiency and characteristics.

In addition, the low power-factor error (0.03% of apparent power) enables precision power-loss measurements, especially in the evaluation of transformer characteristics.

In addition to offering direct keys to access the most important measurement functions, the WT3000 allows the user to set nine different display item patterns in advance, and change between them at will.

The display can be configured to show numerical, waveform, trend or (optionally) harmonic bargraph data.

The WT3000 offers not only the conventional active power and current integration, but also new functions for apparent power and reactive power.

An optional delta calculation function allows the user to calculate individual phase voltages from the line voltage measured in a three-phase/three-wire system.

This makes it possible to determine the phase voltage in motors and other items under test where no neutral lines are present.

The harmonic measurement option allows the instrument to handle both normal and harmonic measurement data simultaneously.

This enables the user to measure total harmonic distortion while simultaneously monitoring total voltage, current and distortion factor without altering the measurement mode.

It also makes it possible to calculate the phase angle of three-phase power between phases or across input elements.

Also available as an option is a 20-channel digital/analogue convertor output, which allows measured values to be output as +/-5V (full-scale) DC voltages from a connector on the rear panel.

Measured parameters can be output on up to 20 channels simultaneously.

In addition to the standard two channels of frequency measurement, a six-channel frequency measurement option is available, allowing voltage and current frequency to be measured separately from the instrument's I/O as well as voltage and current frequencies of other items under test at the same time.

The motor version of the WT3000 incorporates a number of additional motor/inventor evaluation functions, allowing the calculation of motor and total efficiency with high accuracy.

In addition to voltage, current and power measurement, it can take analogue or pulse inputs from torque meters and speed sensors and calculate a range of parameters including torque, revolution speed, mechanical power, synchronous speed, slip, motor efficiency and total efficiency.

The WT3000 is fitted with a GPIB interface as standard, with RS232 and Ethernet interfaces available as options.

It is also fitted with a standard PC card slot.

A future USB option will allow the use of USB memory sticks as well as providing a PC communication interface.

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