The WT3000E provides engineers with a solution for verifying product efficiency and compliance to IEC harmonic and flicker standards. The WT3000E is ideal for the design and testing of appliances, solar inverters, motor drives, lighting systems, uninterruptible power supplies, transformer testing, aircraft power systems, and other power conversion devices.
With a basic power accuracy of ±0.04% (total), DC and 0.1 Hz1 MHz measurement bandwidths, and up to four input elements, the WT3000E provides highaccuracy measurement of I/O efficiency.
High accuracy and wide frequency range:
Basic power accuracy:
±(0.01% of reading + 0.03% of range)
Frequency range:
DC, 0.1 Hz to 1 MHz
Low Power Factor Error:
Power factor error when cos ø=0:
0.03% of S where
S is the reading value of apparent power
ø is the phase angle between voltage and current
Current Range:
Direct Input:
0.5 / 1 /2 / 5 / 10 / 20 / 30 [A] or 5 / 10 / 20 / 50 / 100 / 200 / 500 [mA], 1 / 2 [A] *
* 2A and 30A input elements can be installed together in one unit.
External Input:
50m / 100m / 200m / 500m / 1 / 2 / 5 / 10 [V]
Standard Features  Optional Features 


Example of basic characteristics showing the WT3000E’s high precision and excellent stability
Checking phase voltage when you measure line to line voltage
This function allows you to calculate individual phase voltages from the line voltage measured in a threephase, threewire (3V3A) system. RS line voltage can be calculated in systems measured from a threephase, threewire method (using two elements). This is useful when you want to determine the phase voltage in motors and other items under test with no neutral lines. Line to line voltage and phase current (measurements equivalent to 3V3A) can be estimated in systems not measured from a threephase, threewire configuration (using two elements).
When you have fluctuating data or during motor evaluation *you may need to capture rapidly changing phenomena such as during load fluctuations in a motor. These tasks can be handled effectively with the cyclebycycle measurement function. The function takes measurements of parameters such as voltage, current, and active power for each cycle, then lists the data on screen in a time series. Up to 3000 data (measurements of signals from 0.1 Hz to 1000 Hz) can be saved in CSV format.
* Requires the motor evaluation option (/MTR)
The range indicator on the WT3000E is an easytoread sevensegment green LED, so the set range can be monitored at all times. The range can easily be switched using the up and down arrows next to the display.
Cursor keys can be used to move the screen cursor in four different directions, so it is easy and intuitive to set scaling factor and other settings.
The WT3000E has nine item pages for displaying measurement values. Once you set the measurement parameters you want displayed on a particular item page, you can easily switch between entire groups of displayed parameters. For example, the following settings make it easy to switch and compare data:
Page 1: Voltage, current, active power, and current frequency for input element 1
Page 2: Voltage, current, active power, and current frequency for input element 2
Page 3: Voltages for input elements 1, 2, 3, and 4
Page 4: Currents for input elements 1, 2, 3, and 4
Page 5: Power for input elements 1, 2, 3, and 4
The WT3000E lets you display input signal waveforms in addition to numerical value data. This means you don't need to connect a special waveform analyzer just to check signal waveforms. ^{1}
In addition, the optional advanced calculation function lets you display vectors and bar graphs for enhanced visual presentation. The information display shows voltage range, current range, filter, and scaling value altogether, making it easy to check your settings. ^{2}
^{1} Waveforms up to approximately 10 kHz can be displayed accurately.
^{2} More than two sets of same type input elements are required.
The fast update rate allows you to precisely capture rapidly changing transient states in the measurement subject.
* The WT3000E switches between two different calculation systems depending on the data update interval. See other page for details.
The WT3000E has compensation functions for highprecision measurements. These functions can compensate for instrumentrelated losses resulting from the power meter’s internal impedance as well as losses related to wiring during measurement with two power meters. The following compensation functions are provided to compensate for instrumentrelated losses:
When measurements are performed using two power meters with threephase, threewire wiring, errors may occur if current flows to the middle wire (or if there is a leakage current). The WT3000E has a function to compensate for such errors. Even when measurements are performed with two power meters (requires measurement with threephase threewire (3V3A) wiring), the current flowing to the middle wire is calculated, and a corresponding correction value can be added to the power measurement. This improves the accuracy of power measurements.
As many as twenty userdefined formulas can be set in the WT3000E. These equations can be used to calculate various parameters, such as mean active power (see "A variety of integration functions" below).
This function can be used to set up to four efficiency calculation formulas.
The crest factor is the ratio of the waveform peak value and the RMS value. 
When checking the measurable crest factor of our power measuring instruments, please refer to the following equation.
* However, the peak value of the measured signal must be less than or equal to the continuous maximum allowed input.
* The crest factor on a power meter is specified by how many times the peak input value is allowed relative to rated input value. Even if some measured signals exist whose crest factors are larger than the specifications of the instrument (the crest factor standard at the rated input), you can measure signals having crest factors larger than the specifications by setting a measurement range that is large relative to the measured signal. For example, even if you set CF = 3, CF5 or higher measurements are possible as long as the measured value (RMS) is 60% or less than the measuring range. Also, for a setting of CF = 3, measurements of CF = 300 are possible with the minimum effective input (1% of measuring range).
Voltage, current, power, and other measured data can be stored to the unit's approximately thirty megabytes of internal memory. These data can be saved in binary or ASCII format on a PC card or USB memory*.
* The USB port (for peripherals) comes with the /C5 option.
Each measured item can be stored at every data update interval. You can specify to store only the desired measured items, thus saving memory.
Files saved in ASCII format can be opened in generalpurpose applications such as Excel allowing display of data in graphs.
* Please note that data saved in binary format can only be manipulated using dedicated software to be made available by Yokogawa.
Excel Example 
A wide variety of optional functions make it easy to perform sophisticated power evaluations.
When you purchase a WT3000E from Yokogawa, you can select just the options you need. This approach lets you maximize performance at a lower cost.
The Advanced Calculation Function provides for wide bandwidth harmonic measurement, IEC compliant harmonic measurement (requires harmonic measurement software), FFT calculation, waveform calculation functions, and saving of waveform sampling data.
Enables harmonic measurement over wide bandwidths. Supports measurement of harmonic signals beyond those of the harmonic measurement function in normal measurement mode. This option allows for harmonic analysis on waveforms with a fundamental frequency range of 0.1 Hz–2.6 kHz (*1). You can measure up to the 50th order harmonic at 1 kHz fundamental.(*2).
*1 0.1–10 Hz using an external sampling clock.
*2 Harmonic measurement of up to the 20th order possible in the 1 kHz to 2.6 kHz range.
This function enables simultaneous measurement of normal and harmonic data, which was not possible with previous Yokogawa models. With the WT3000E you can simultaneously confirm total voltage and current as well as the distortion factor and fundamental wave without switching modes, this allows for more accurate and efficient measurement of the power supply quality, the fundamental wave of motor drive voltage, and other factors.
The IEC harmonic measurement mode meets the window width requirement of the latest IEC harmonic standard (10 cycles of 50 Hz and 12 cycles of 60 Hz). Also, this mode allows users to use the 761922 harmonic measurement software to perform tests conforming to IEC 6100032 and IEC61000312.
* These modes cannot be used at the same time.
Two FFT calculations can be performed simultaneously on waveform data of measured voltage and current. You can select a resolution for FFT of 1 Hz or 10 Hz. FFT analysis of up to 100 kHz can be performed.
Up to two waveform calculations and other Waveform Calculation functions can be used at once. If you create a formula that multiplies voltage and current waveforms, you can confirm an instantaneous power waveform on screen. Waveform Calculation data can be saved in CSV or WVF format.
All captured voltage and current waveform data (200 kS/s), calculated waveforms, and FFT calculated waveforms can be saved. You can choose to save in CSV or WVF format, and to save to PC card or USB memory (/C5 option).
In addition to the standard two channels of frequency measurement, a sixchannel frequency measurement option is also available. This option provides frequency measurement of voltage and current on all eight channels (with input elements 1 through 4 installed). This is necessary when you want to measure voltage and current frequency from the instrument’s I/O as well as voltage and current frequencies of multiple items under test at the same time.
* The range is 0V to 5V for some functions, such as frequency measurement
The optional builtin printer is installed on the front side of the WT3000E, so it is easy to use even if the WT3000E is mounted on a rack. The printer can be used to print data and waveform memos.
The Auto Print function allows you to set a time interval at which measured values are automatically printed on the builtin printer. You can also set a start and stop time in order to record data over a desired time period. You can also specify to print only the desired measured items.
The VGA port can be used to connect an external monitor in order to view numerical value data and waveforms on a larger screen. This capability is useful if you want to simultaneously check large amounts of data on a separate screen, or view data in a separate location.
A USB port for peripherals with type A connectors can be included with the WT. The various kinds of data stored in the main unit such as voltage, current, and power, can be saved in binary or ASCII format on a peripheral such as a USB memory. You can also connect a keyboard for easy input of userdefined math expressions.
The USB port (type B connector) on the rear panel of the WT3000E allows data communications with a PC¹. Also, instruments with this option installed can be used in conjunction with the communication functions of PC application software for data acquisition via USB².
* USB stands for universal serial bus. USB is a standard designed to provide connectivity across a wide range of PC peripherals and other devices through the use of a common communication mechanism.
The option conforms to 100BASETX and 10BASET and provides for data exchange via Ethernet. It supports file transfers via FTP server, as well as FTP client (network drives), LPR client (network printers), and email (SMTP client) functions.
* The WT3000E does not have a builtin hard disk. The FTP server function is available when a PC card or USB memory is inserted or connected to the PC.
This function enables measurement of voltage fluctuations/flicker in compliance with EN6100033 and IEC61000311. It can measure relative working voltage change, maximum relative voltage change (dmax), relative voltage change time (dt), shortterm flicker value (Pst), and longterm flicker value (Plt). The initial limit values for the individual parameters are set in accordance with the IEC standard.
IEC6100032, IEC61000312, JIS C 3100032
(Advanced Calculation Function /G6 and software for testing standards compliance)
IEC6100033, IEC61000311
(Voltage fluctuation/flicker measurement, with the /FL option)
Support for IEC and JIS Standards Testing
Compared to the reference product WT1600, CO_{2} emission was reduced by about 20%. Results of Life Cycle Assessment 
BNCBNC 1m. For connection to simultaneously measurement with 2 units, or for input external trigger signal.
BNCBNC 2m. For connection to simultaneously measurement with 2 units, or for input external trigger signal.
For connection the external input of the WT3000 to the current sensor.
Length: 50cm
A set of 0.8m long red and black test leads, used in combination with a pair of optional 758922 or 758929 alligatorclip adapters.
Adapters for fitting a 4mm banana plug to a fork terminal. Set contains one black and one red clip. 1000 VrmsCAT II.
Rated at 300 V. Attaches to the 758917 test leads. Sold in pairs.
For conversion between BNC and female banana plug
Applicable for DL750/DL750P, SL1000 & SL1400.
Rated at 1000V. Attaches to the 758917 test leads. Sold in pairs.
Screwfastened adapters. Two adapters in a set. 1.5 mm Allen Wrench.
Printer Paper Roll
Thermal paper (10m) for WT1600, WT 1800, WT3000, & WT3000E  1 roll
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If a product uses power, then power consumption and power quality measurements must be made as part of product design and test. These measurements are essential to optimize product design, comply with standards and provide nameplate information to customers.
This article will discuss best practices for making these measurements, starting with power measurement basics and proceeding to the types of instruments and associated components typically used to make measurements. The article will conclude with realworld examples, which apply the information imparted earlier in the article to solve practical measurement problems. Although most of us have been exposed to basic power measurement equations, a primer is helpful to summarize this information and to show how it applies to product design and test.
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The accuracy of a measurement instrument varies with the range over which a reading is measured.
But what if different manufacturers specify this range differently in their instruments?
This article explores the impact of range definitions on measurement accuracy and how one can be mindful when comparing accuracy across instruments.