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Motors & Drives

Yokogawa WT1800 High Performance Power Analyzer
Product Overview
This new addition to Yokogawa's highly recognized digital power analyzer product line offers innovative measurement functions which benefit the engineer with electrical power measurements. It is the ideal measurement solution for testing Product Efficiency, and the design of Inverters, Motor Drives, Lighting Systems, Uninterruptible Power Supplies, Aircraft Power Systems, Transformer Testing and other power conversion devices.

What's New
  • Released firmware Version 2.25


Many features are available that are a first in the power measurement industry *1

Measurement - High-precision, wide range, fast-sampling, simultaneous harmonic measurement

Voltage and current frequency bandwidth 5 MHz (-3 dB, typical)

WT1800 Features1Faster switching frequencies increasingly require measurements in a wider range. The WT1800 provides a voltage and current frequency bandwidth (5MHz) 5-fold wider than the previous measurement range and is capable of more correctly capturing fast switching signals.

Reduction of low power-factor error to 0.1% of apparent power (2/3 of previous model)

WT1800 Features2 1A power-factor error is one of the important elements to ensure high-accuracy measurements even at a low power factor. The WT1800 has achieved a power-factor error (0.1%) that is 2/3 of the previous model, in addition to a high basic power accuracy of ±0.1%.

Wide voltage and current range allowing direct input

WT1800 Features3Direct input of measurement signals makes it possible to measure very small current that can hardly be measured with a current sensor. The WT1800 provides a direct input voltage range from 1.5 V to 1000 V (12 ranges) and a direct input current range from 10 mA to 5 A (9 ranges) or from 1 A to 50 A (6 ranges).

0.1 Hz low-speed signal power measurement and max. 50 ms high-speed data collection

WT1800 Features4The frequency lower limit has been reduced to 0.1 Hz from the previous 0.5 Hz (5-fold lower than the previous model) to meet the requirement for power measurements at a low speed. Furthermore, high-speed data collection at a data update rate of up to 50 ms has been inherited. In addition to normal measurement data, up to the 500th order harmonic data can be measured and saved simultaneously. The data update rate can be selected from nine options from 50 ms to 20 s.

* Harmonic measurement at the 50 ms data update rate is possible up to the 100th order.

Particular voltage and current range selectable

WT1800 Features5Wide voltage and current input ranges have the advantage of extending the measurement application range. However, the downside is that the response time of the auto range tends to slow down. A range configuration function solves this problem. Since only the selected range (effective measurement range) can be used, the range can be changed up or down more quickly.

* Comparison with Yokogawa's previous model WT1600

*1: Applicable to a general-purpose high-precision three-phase power analyzer as of February 2011 (according to Yokogawa's survey).

Support for Energy Conservation Technologies and Sustainable Energy Development

WT1800 Dual Dual Harmonic Measurement

The perspective of the efficient use of energy is boosting demand for inverters to convert 50Hz or 60 Hz AC power to DC power, grid connection controllers to control reverse power flow occurring due to excess power, and battery chargers/dischargers. The WT1800 is capable of simultaneously measuring the harmonic distortion of the input and output current of these devices. Challenging the common wisdom that "harmonic measurement is limited to a single line," the WT1800 is capable of performing two-line simultaneous harmonic measurements. The WT1800 is also capable of measuring up to the 500th order harmonic even at high fundamental frequencies such as a 400 Hz frequency.

Specifications & Detail

New functions greatly support power measurements

Dual harmonic measurement (option)

WT1800 Features5The industry's first two-line simultaneous harmonic measurement is available, in addition to simultaneous measurement of harmonic and standard measurement items such as voltage, current, and power values. Previously, harmonic measurements of input and output signals

had to be performed separately. With the WT1800, harmonic measurements of input and output can be performed simultaneously.

Two-channel external signal input is available for power measurement and analog signal data measurement

WT1800 Functions1(option available in combination with the motor evaluation function) Power measurements can be performed together with physical quantity data such as solar irradiance or wind power in wind generation.

Electrical angle measurement is also supported.

WT1800 Functions2Motor evaluation function allowing A-phase, B-phase, and Z-phase inputs (option available in combination with external signal input) Pulse or analog signals can be input for rotation speed and torque signal measurements. The motor evaluation function of the WT1800 makes it possible to detect the rotation direction and measure the electrical angle, which is not possible with Yokogawa's previous model.

High Speed Data Capturing (option)

WT1800 HighSpeedDataA New High Speed data capturing /HS option can measure ∑Urms, ∑Irms and ∑P from single phase (DC signal) and three phase devices every 5 ms (When external syncronisation is OFF) or, 1 ms to 100 ms when External Sync is ON (depending on the frequency of the clock signal ).

It outputs data in 1 s blocks to internal/external memory or to a PC through a communications interface.

Existing products can measure three phase power values every 50ms however, a 50ms data update rate is typically insufficient to be able to analyze motor start up transients or the turn-on behavior of devices.

High Resolution Display

All Data of 6-input, Single/Three-phase Devices can be Viewed on a Single Screen

Important Information is Displayed in a Concentrated Format on High Resolution 8.4-inch XGA Display

A high resolution display with a resolution about 2.6-fold higher than Yokogawa's previous model* is employed. More setting information and measurement data can be displayed

*Comparison with Yokogawa's previous model WT1600

Measurement data can be displayed on a single screen, along with the respective detailed setting information of 6 inputs, such as a voltage range, current range, synchronization source, wiring system, and filter. You do not need to switch display screens frequently to confirm the settings.

WT1800 6Element 1

With the WT1800, the data update rate can be selected from 9 options from the fastest data update rate of 50 ms to an update rate of 20 s for low-speed measurements. For example, if you want to save the average data at a 1-minute interval and inappropriately set the update rate of 50 ms, measurement results may be not correct because data can be saved only at a 1-minute interval (once every 20 times).Such a risk can be avoided by setting the update rate that is suited to the interval at which you want to save data.

Computation Range Display

Direct display of primary current values
WT1800 Computation The setting ranges of voltage and current are usually displayed with voltage and current signal levels that are input to the power analyzer. The WT1800 provides not only this direct display but also added a new computation range display function to the external current sensor range. This function allows you to display the primary current range for the voltage output type current sensor. It allows you to intuitively set a range that is suited to the primary measurement signal level.

User-defined event function

Capture only a particular event
WT1800 User Defined The data saving function of the WT Series is capable of continuously saving data for a long period of time. However, to check an irregular event, data must be retrieved using spreadsheet software. The event trigger function allows you to set the high and low limits and only trigger data that falls into or out of that range to be saved.

Individual Null Function

Function to reset only a particular input signal to zero
WT1800 Null Function A null function allows you to reset the offset value to zero in the connected state. Previously, all inputs could only be collectively set to ON or OFF. With the WT1800, the null value for each input can be set to ON, HOLD, or OFF. In a motor evaluation test, the offset value for only a particular input can be reset to zero. This makes it possible to perform a more accurate motor evaluation test.

Help Function

Display the manual on the screen
WT1800 Help Function

English help menu supports measurement
Display the manual on the screen Frequently used functions (keys) can be performed without the instruction manual. You may, however, want to use a new function during evaluation. The WT1800 includes a built-in instruction manual on the functions, so if a new operation is required, you can read the explanation of the function on the screen.

Line Filter

Capture an original signal masked by high frequency component

WT1800 Line Filter 1WT1800 Line Filter 1a
WT1800 Line Filter 2WT1800 Line Filter 2a
WT1800 Line Filter 3WT1800 Line Filter 3a

In power evaluation such as an inverter waveform and distorted waveform, measurement values are affected by high frequency component. A new digital filter function makes it possible toremove unnecessary high frequency components superimposed on signals. A filter can be independently set for each input element. An analog filter for 1 MHz/300 kHz, and digital filter that can be set from 100 Hz to 100 kHz in increments of 100 Hz are available as standard.

Range configuration function

High-speed range setting suited to input signals

WT1800 Range Config 2

WT1800 Range Config 1

A new range configuration function is available. It allows you to choose a particular voltage and current input range (effective measurement range). Eliminating unnecessary ranges has made it possible to achieve optimal range setting that is faster than Yokogawa's previous model*. This allows more quicker tracking of signal changes. If the peak goes over the limit, you can switch to a preset range. This is effective in reducing the production time for a repeat test, such as setting to OFF, 100 V, OFF and so on, which is performed frequently on the production line.

Numerical and harmonic bar graphs

Dual Harmonic Measurement

WT1800 Dual Harmonic A harmonic measurement option (/G5) makes it possible to display both numerical data and bar graphs to help understand measurement data visually. In addition, a dual harmonic measurement function (/G6) makes it possible to measure and display two-line harmonic bar graphs (dual harmonic) simultaneously.


Support for 6 split screen displays

WT1800 Waveform A high resolution display makes is possible to split the waveform display into up to 6 split screens. This makes it possible to split the display of signals between the input and output of a three-phase inverter and display them simultaneously. Waveform display allows you to display waveforms for the voltage alone or the current alone, or arbitrarily set the display position, so you can also display only the signals you want to compare one above the other.

Dual Vector

Simultaneous two vector displays

WT1800 Dual Vector

Fundamental harmonic voltage and current signal phase vectors can be displayed. With Yokogawa's previous model, vector display is limited to a single line. With the WT1800, Dual vectors can be displayed. In addition, combination display of vectors and numerical values is also possible. This allows you to view the numerical parameters and voltage and current phase status visually.


Capture efficiency changes visually

WT1800 Trend When evaluating inverter efficiency, sometimes small efficiency changes can hardly be recognized with just numerical values. Trend display makes it possible to display measurement values and measurement efficiency as trend data in time series to help capture even small changes visually. Trend data over several minutes or several days can be displayed.

Setting Information

Combination display of information and numerical screens

WT1800 Setting The screen can be split into two, with one above the other, and two types of screens can be displayed simultaneously. Screen can be selected from Numerical, Waveform, Trend, Bar Graph, and Vector displays. Another new function allows you to press the NFO button on the Numerical screen to display the setting information in the upper row and automatically scale down the numerical nformation displayed in the lower row.


Customize display screen

WT1800 Custom Image data can be loaded onto the screen and the position and size of the numerical data can be specified.

The display screen can be customized so that the corporate logo of your company is displayed on the screen, or only the measurement items you want to view, such as input and output efficiency or frequency, are displayed one above the other.

*The data for the created screen needs to be loaded from a USB storage device.

Data Sheet & Downloads