WT1800E High-Performance Power Analyzer

The WT1800E is a high-performance power analyzer that guarantees power accuracy of 0.05% of reading plus 0.05% of range. It is capable of harmonics analysis up to the 500th order of a 50/60 Hz fundamental frequency. With up to 6 input channels, a wide range of display and analysis features, and PC connectivity, the WT1800E is the ideal tool for engineers to accurately measure power characteristics and efficiency of electrical devices.

Yokogawa Special Offers and Discounted Products

Free Fundamentals of Power Poster

One Instrument for your Complete System Measurement Needs

  • Simultaneous Electrical Power Measurements of up to 6 Voltages and 6 Currents at 2MS/s (16 bits)
  • Mechanical parameters such as Rotational Speed & Direction, Torque, Slip, Electrical Angle, Mechanical Power, and Motor Efficiency


Peace of Mind with Guaranteed Accuracy

  • Basic Power Accuracy of 0.05% of reading +/- 0.05% of range, guaranteed from 1% to 110% of the selected range
  • Direct Inputs for Voltage & Current, plus an External Input for Sensor connections
  • Independent Range Configuration with Selective Auto-ranging for repetitive production testing


Say Goodbye to Unwanted Harmonics

  • Analyze up to 500th order of Harmonics for 50/60Hz fundamental signals
  • Multiple harmonic parameters such as THD, HDF, THF, and Impedance
  • Dual Harmonic feature to analyze both input and output of inverters


The WT1800E guarantees a power accuracy of 0.05% of reading plus 0.05% of range and is capable of harmonics analysis up to the 500th order of a 50/60 Hz fundamental frequency. With up to 6 input channels, a wide range of display / analysis features, and PC connectivity, the WT1800E is the measurement solution for a broad range of power efficiency and harmonic analysis applications.

  • Basic power accuracy: 
    • 0.05% of reading
    • 0.05% or range
  • Harmonics analysis up to the 500th order of a 50/60 Hz fundamental frequency
  • Up to 6 input channels at 2 MS/s (16 bits)

6 inputs on a high-resolution display

Make simultaneous measurements on up to 6 inputs at 2 MS/s (16 bits). The high resolution 8.4 inch XGA display of the WT1800E allows split screen viewing of up to 6 waveforms and can display up to 12 pages of diverse measurement parameters making it ideal for efficiency tests of inverter driven motors, renewable energy technologies and traction applications like pumps, fans, and hybrid/electric vehicles. The unit can also display measurements in vector format or trending in time.

WT1800E High Resolution Display

Guaranteed accuracy across a wide range

Measure accurately at a wide range of voltage, current and frequency conditions. The basic power accuracy of the WT1800E is guaranteed between 1% to 110% of the selected voltage and current range. This equates to voltages from 15 mV to 1100 V rms and currents from 0.1 mA to 5.5 A rms (for a 5 A input element) and 10 mA to 55 A rms (for a 50 A input element). The unit is also accurate during large phase shifts and high frequencies thanks to the minimized influence of the low power factor error (±0.07% of apparent power).

Range configuration

Track signal changes faster by eliminating unnecessary range changes. The WT1800E’s range configuration function allows users to select input ranges based on their specific use cases so that optimal range settings are achieved quicker. This reduces the time during repetitive production tests, such as setting to OFF, 100 V, OFF and so on, which is performed frequently on the production line.

Harmonic analysis

Analyze harmonics up to the 500th order for a 50/60 Hz fundamental even at a data update interval of 50 milliseconds. The WT1800E features two options for analyzing harmonics in addition to power parameters.

  • Harmonic measurement mode (/G5 option) for fundamental wave, harmonic components and total harmonic distortion (THD)
  • Dual Harmonic option (/G6 option) for side by side measurement of harmonics on two different sources for example input and output of inverters, variable speed motors, lighting ballasts, UPS, etc.

WT1800E Harmonic Analysi

Power integration and auto ranging

Measure energy bought/soldn grid connections or charged/discharged in batteries. The WT1800E’s Power integration function integrates instantaneous values for both positive and negative readings. It also measures total energy (Wh) and current (Ah) when load conditions vary widely such as in devices transitioning from standby to operation mode. Should an input signal start to fall out of the expected range, this function can automatically adjust the range while continuing to integrate the measured values.

High-speed data capture

The high-speed data capturing function can measure Sigma-Urms, Sigma-Irms, and Sigma-P from DC signal and three phase devices every 5 ms when External Synchronization is OFF. It can also update at 1 ms to 100 ms when External Synchronization is ON depending on the frequency of the clock signal.

Flexible & automatic data updates

Manually or automatically set measurement intervals. The WT1800E offers 9 data update interval between 50 ms to 20 s but can also follow fluctuating input frequencies by changing the data update rate automatically. This is useful when measuring devices like motors whose input signal frequency varies with RPM.

WT1800E Flexible

DC power supply for AC/DC current sensors (/PD2 option)

The WT1800E can be equipped with a DC power supply for the CT series of AC/DC current sensors. By using dedicated connection cables and shunt resistors, the WT1800E can measure large currents. Improved S/N ratio and noise immunity is achieved by connecting the sensors in this way.

WT1800E Flexible 2

* /EX1 to /EX6 option must be installed in the WT1800E to be able to use the Shunt Resistor Box.

Motor evaluation function

Measure more than just electrical parameters. The motor evaluation function enables measurement of rotation speed and direction, torque, mechanical power, synchronous speed, slip, electrical angle, motor efficiency and total system efficiency from the analog or pulse outputs of rotation and torque sensors.

WT1800E Motor Evaluation Function

761941 WTViewerE Application Software for WT3000E/ WT3000/ WT1800E/ WT1800/ WT500/ WT300E/ WT300

WTViewerE software enables PC connectivity for Yokogawa power analyzers such as the WT3000E, WT1800E, WT500 and WT300E through Ethernet, USB, GPIB or RS232. This connectivity allows users to easily control, monitor, collect, analyze, and save measurements remotely.

WT1800E WTViewerEfree Application Software

WTViewerEfree application software

Easily view, control and download measurements from your PC. The WTViewerEfree is free software that connects the WT1800E to a PC via a communications interface making numeric, waveform, trend and harmonic data easily accessible via PC.

WT1800E WTViewerEfree Application Software

User-defined events and computations

The event trigger function of the WT1800E allows users to set limits for the capture of readings that fall into or out of a specific range of power, current or other parameters. Data that meets the trigger conditions are stored, printed, saved to a USB memory device etc. Users can also define and use up to 20 expressions for custom calculations.

Example of basic characteristics showing the WT1800E’s high precision and excellent stability

WT1800E Example Of Frequency Versu Power Accuracy Characteristic At Unity Power Factor

Example of frequency versus power accuracy characteristic at unity power factor

Example Of Effect Of Common Mode Voltage On Reading

Example of effect of common mode voltage on readings

WT1800E Total Power Error With Rated Range Input For An Arbitrary Power Factor 50 60 Hz

Total power error with rated range input for an arbitrary power factor (50/60 Hz)

WT1800E Example Of Frequency Versu Power Accuracy At Zero Power Factor

Example of frequency versus power accuracy at zero power factor

Interfaces & Connections

WT1800E Front Connection Interface

Standard Features Optional Features
  1. External Media Slot
  2. Element Setting
  3. U/I range display
  4. Display Settings
  5. Measurement item selection
  6. Integration Settings
  7. Data Saving
  1. Built-in Printer (/B5 Option)
  2. Current Sensor Power (/PD2 Option)

WT1800E Back Connection Interface

Standard Features Optional Features
  1. Voltage Input Terminals
  2. Current Input Terminals
  3. GP-IB port
  4. BNC Connector for Two-System Synchronized Measurement
  5. Ethernet Port (1000BASE-T/100BASE-TX)
  6. USB Port (PC)
  1. External Current Sensor Input Terminals (/EX Option)
  2. Torque and Speed Input Terminals (/MTR Option)
  3. D/A Output (/DA Option)
  4. RGB Port (/V1 Option)

Two types of Input Elements

Basic Power Accuracy: ±(0.05% of reading + 0.05% of range)*1
Measurement Bandwidth: DC, 0.1 Hz to 1 MHz
Low Power Factor Error: Power factor influence when cosø = 0

  1. 0.07% of S
    S is reading the value of apparent power
    ø is phase angle between voltage and current

Temperature range: 23 ±5˚C
Current Range:

  • Direct Input: 1/2/5/10/20/50 A*2
    • 10/20/50/100/200/500 mA, 1/2/5 A*2 (50 A and 5 A input element can be installed together)
  • External Input: 50/100/200/500 mV, 1/2/5/10 V*2

Voltage Range: 1.5/3/6/10/15/30/60/100/150/300/600/1000 V*2
Effective input range: 1% to 110%
Data Update Interval: 50 ms to 20 s or Auto

*1 Please refer to “specifications” in detail
*2 Voltage range and current range are for crest factor 3

WT1800E Input Module

Both 5A and 50A input elements can be installed in a single unit. This enables engineers to use a single WT1800E for multiple applications such as standby power measurement and the evaluation of various operating modes of the device under test.

The WT1800E is a versatile instrument, unlocking precision power measurement capabilities for researchers, designers and engineers working on a wide variety of applications in energy efficiency and conservation and renewable energy. Whether it is for the manufacture of energy efficient devices and appliances, hybrid/electric vehicles or renewable energy technologies, the WT1800E is a universal meter for power electronic measurements and energy analysis. Key applications include:

  • Electric, Hybrid Electric and Plug-in Hybrid Electric Vehicles
  • Industrial equipment such as Inverters, Motors and Pumps
  • Renewable energy technologies such as Solar and Wind power
  • Office and Home appliances like Air conditioners and Refrigerators
  • IT Data center equipment like Servers, Routers and Switches
  • Battery charging and Portable devices
  • Ballasts, LEDs & Fluorescent lighting
  • Aircraft Power systems

Inverter and motor testing

WT1800E Inverter Motor Testing


Electric and hybrid vehicles have many electrical and mechanical components and therefore an overall performance evaluation requires the efficiency measurement of both. With 6 channels of power inputs, flexible operation and a wide bandwidth, the WT1800E is ideal for efficiency tests between the input and output of inverters. An optional motor evaluation function enables the measurement of rotation speed and changes in torque.

WT1800E Phase

Delta computation

Obtain the line and phase voltages from the sums and differences of the instantaneous values of voltage and current in each element.

  • Line voltages and phase currents that are not measured are computed in the three-phase three-wire system (Figure 1).
  • Star-delta conversion: Line voltage is computed from the phase voltage using the three-phase four-wire system data.
  • Delta-star conversion: Phase voltage is computed from the line voltage in the three-phase three-wire system (3V3A system) (Figure 2).

WT1800E Advantages

Wide bandwidth and High speed sampling

The WT1800E is capable of 16-bit high resolution and 2 MHz sampling making it possible to measure faster signals with higher precision.

Motor evaluation: Electrical angle/rotation/ direction

Measure rotation speed, torque, and output (mechanical power) of motors from analog/pulse inputs of rotation or torque sensors.

Harmonics and dual harmonics

Simultaneously measure distortion factors like THD, fundamental and harmonic components. Harmonics up to the 500th order can be measured even at 50 ms data update rate. Users can also measure harmonics on two different sources simultaneously.

Battery charge/discharge measurements

In integrated measurement, the battery charge and discharge can be evaluated. Instantaneous positive and negative values captured at a high-speed sampling rate of 2 MS/s are integrated.

Line filter to remove high frequency components

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

Efficiency of renewable energy systems

WT1800E Power Flow Of Photovoltaic Power


Energy generated by photovoltaic cell modules and wind turbines is converted from DC to AC by a power conditioner. Minimizing losses in these conversions improves the efficiency in the overall energy system. The WT1800E provides up to 6 power inputs per unit for measuring voltage, current, power, and frequency (for AC) before and after each converter, as well as the converter and charging efficiencies.

WT1800E Typical Voltage Curret And Power

Measuring instantaneous peak power

In photovoltaic power generation, an MPPT control varies the voltage to maximize energy harvested from the solar panel. The WT1800E can measure not only the voltage, current, and power but also the voltage, current, and power peak values for both plus (+) and minus (−) sides.

WT1800E Advantages

Multiple channels and wide input range

Evaluate Power conditioner efficiency using 6 input channels for simultaneous measurements from the inputs and outputs of boost converter, inverter, and storage battery. Direct input terminals (voltage range: 1.5 V to 1000 V and current range: 10 mA to 5 A or 1 A to 50 A) make it possible to perform high-precision measurements without using a current sensor.

Harmonic distortion factor measurement

Voltage fluctuations and harmonics flow into the power system due to reverse power flow. A harmonic measurement function enables measurement of harmonic components to compute and display total harmonic distortion (THD).

Ripple factor and power loss measurements

A user-defined function makes it possible to compute power loss, DC voltage and DC current ripple factors between the input and output. Up to 20 arithmetic expressions can be set. Display names for the arithmetic operations F1, F2, and so on can be freely changed.

Typical arithmetic expressions

  1. DC voltage ripple factor = [(Voltage peak value (+) – Voltage peak value (−))/2 × DC voltage value (mean)] × 100
  2. Power loss = Output power – Input power

Energy bought/sold and charged/discharged

Measure the amount of power sold/bought in grid interconnection and of battery charge/discharge. Measure the amount of power sold/ bought in grid interconnections and in battery charge/discharges. The WT1800E enables the integration of current (q), apparent power (WS), reactive power (WQ), as well as the effective power integration in sold/bought power and charge/discharge modes. Furthermore, a user-defined function makes it possible to calculate the Average active power within the integration period.

Efficiency of inverter-motor in electric vehicles

WT1800E Inverter Motor In Electrical Vehicle


The WT1800E supports power measurements on up to 6 input channels making it ideal for evaluating the efficiency between the input and output of an electric vehicle. An optional motor evaluation function makes it possible to simultaneously monitor voltage, current, and power changes, as well as changes in rotation speed, torque and mechanical power.

WT1800E Typical Repetitive High Speed Charging

Battery charge/discharge measurements

In integrated measurement, the battery charge and discharge can be evaluated. Instantaneous positive and negative values captured at 2 MS/s high-speed sampling rate are integrated, and each of the total values is displayed.

WT1800E Advantages

Wide bandwidth and High speed sampling

The WT1800E is capable of 16-bit high resolution and 2 MHz sampling making it possible to measure faster signals with greater precision.

Harmonics and dual harmonics

Motor testing is performed at various rotation speeds. The WT1800E supports a lower limit frequency of 0.1 Hz to enable measurement of harmonics at a very low motor rotation speed without using an external sampling clock.

Motor evaluation: Electrical angle/rotation/direction

Measure rotation speed, torque, and output (mechanical) power of motors from analog/pulse outputs of rotation or torque sensors.

Individual null function: offset correction for each input

A common problem when testing inverter motors is the presence of ambient noise that can mean test values are non-zero even before testing begins. The WT1800E’s null function allows users to enable, disable or reset the offset values for voltage, current and motor input signals of each element separately.

DA output and remote control

Users may want to check changes in data, along with other measurement data (temperature, etc.) at the same time that communication data, such as voltage, current, power, and efficiency are required. A DA output function allows users to generate analog signals on up to 20 channels.

366924 BNC to BNC 1m Cable

  • 366924 BNC to BNC cable for oscilloscope 
  • 1m BNC wire
  • Simultaneous measurement with 2 units
  • Input external trigger signal

366925 BNC to BNC 2m Cable

BNC-BNC 2m. For connection to simultaneously measurement with 2 units, or for input external trigger signal.

701902/701903 Safety BNC to BNC Cable 1m/2m

  • 701902/701903 Safety BNC to BNC Cable for oscilloscope
  • Safe, high-voltage measurements with DL350, DL950, and SL1000 isolated input modules 
  • 701902: 1000 Vtms-CAT II (BNC-BNC), 1 m
  • 701903: 1000 Vrms-CAT II (BNC-BNC), 2 m

758917 DMM Measurement Lead Set

  • Set of 0.8m long red and black multimeter test leads
  • Used in combination with a pair of optional 758922 or 758929 alligator-clip adapters
  • 1000 Vrms, 32 Arms CAT II

758921 Fork terminal adapter

  • 758921 Fork Terminal Adapters
  • For fitting a 4mm banana plug to a fork terminal
  • One black and one red clip
  • 1000 Vrms-CAT II

A1559WL, A1560WL Dedicated Cable

Dedicated Cables for WT1800E /PD option.

758922 Small Alligator-Clip Adapter 300V

Rated at 300 V. Attaches to the 758917 test leads. Sold in pairs.

A1589WL Direct Current Input Cable

Direct Current Input Cable (with Burden Resistor 2.7 Ohm) for WT1800E /PD2 option.

758923 Spring Hold Safety Terminal Adapter Set

Two adapters in a set (spring-hold type).

B9284LK External Sensor Cable

For connection the external input of the WT3000 to the current sensor.
Length: 50cm

751522/751524 Current Sensor Unit

Current sensor unit accessories for digital power meters and power analyzers.
DC to 100 kHz/1000 a peak guaranteed calibration with power analyzers.

A1628WL Direct Current Input Cable

Direct Current Input Cable (without Burden Resistor) for WT1800E /PD2 option

758924 BNC to Banana Conversion Adapter

For conversion between BNC and female banana plug
Applicable for DL750/DL750P, SL1000 & SL1400.

758929 Large Alligator Clip Adapter 1000V

  • Yokogawa 758929 Alligator Clip Adapter 
  • Rated at 1000V
  • Attaches to 758917 test leads
  • Sold in pairs black/red

758931 Screw-Fastened Safety Voltage Terminal Adapter Set

Screw-fastened adapters. Two adapters in a set. 1.5 mm Allen Wrench.

B8200GD Screw for B8200JQ

Screws for B8200JQ, D-SUB connector

AC/DC Split Core Current Sensor CT1000S

Measure high currents without disassembling existing cabling. Compatible with power analyzers and waveform measurement instruments.

B8200JQ Output connector

D-Sub 9-pin connector with 2 screws
(female on connector side)

B8200JR Load resistor

10 Ω/0.25 W (×4)

B9316FX Printer Paper Roll

Printer Paper Roll
Thermal paper (10m) for WT1600, WT 1800, WT3000, & WT3000E - 1 roll

751535-E4 Rack mounting kit

RACK MOUNTING KIT For an EIA-compliant Single-housing Rack

A1323EZ, A1324EZ, A1325EZ Shunt resistor boxes

Shunt resistor boxes for WT1800E /PD option.

751535-E5 Rack mounting kit

RACK MOUNTING KIT For an EIA-compliant Single-housing Rack

751535-J4 Rack mounting kit

RACK MOUNTING KIT For an JIS-compliant Single-housing Rack

751535-J5 Rack mounting kit

RACK MOUNTING KIT For an JIS-compliant Single-housing Rack


Energy consumption in low-power and standby modes is an important issue due to increased awareness that energy resources are becoming limited and demand for energy-saving household electrical appliances continues to grow. IEC62301 Ed2.0 (2011) and EN 50564:2011 define standby mode as the lowest energy consumption of an appliance not performing its main function, when connected to the mains. IEC62301 Ed2.0 (2011) defines test methods and requirements for both the mains supply and the test equipment. It is crucial that design and test engineers choose highly accurate power measurement tools to confirm that their devices meet these requirements.


【search key】 WT1, WT18, WT180, WT3, WT30, WT5, WT50, WT500, WT


Designing an instrumentation system for high current measurement requires careful consideration of the trade-offs associated with each type of sensing device. The purpose of this application note is to help engineers understand the sensing choices available and the corresponding trade-offs with each technology.


Total efficiency measurement of EV/PHV

  • Power consumption/quality measurements for product design and test
  • Design, compliance, and customer information
  • Best practices
  • Instruments and components
Application Note

This white paper describes the WT1800, a precision power analyzer that has been replaced by the WT1800E, a unit with numerous improvements including better accuracy. Please visit the WT1800E product page to learn more about the WT1800E.

To keep pace with the increasing speed of switching devices in inverters, Yokogawa has developed the WT1800 precision power analyzer with 10 times faster sampling speed and 5 times wider frequency bandwidth compared with previous models. Its basic accuracy is 0.15% and the frequency bandwidth of voltage and current is 0.1 Hz to 5 MHz (-3 dB, Typical) including the DC component. With up to six inputs, a single WT1800 unit can measure the efficiency of three-phase inverters. In addition, the high-speed data capturing mode allows the WT1800 to measure transient power. This paper describes the high-speed, real-time power measurement technologies underlying these functions.


The objective of this paper is to show the close relationship between efficiency and power quality, and provide education on the causes of power quality, types of power quality issues, and provide guidance on measurement considerations.


To programmatically read all 500 harmonic orders measurement values, please use the ":NUMERIC:LIST" command set. The maximum number of items for the :NUMERIC:LIST:VALUE? command is 64.  However, 1 LIST ITEM can ...

  • Power Analyzer Accuracy and Basic Uncertainty Calculator from Yokogawa Test&Measurement 
  • Determine uncertainty in voltage, current, and active power (watts) measurement values
  • Various frequency ranges and wiring systems
Technical Article
Edition 1

This training module covers the following topics:

  • Introduction & Installation
  • Connecting to Instrument
  • Setup, Measure, and Analyze
  • File Operations: Saving and Loading Data
  • Video Demonstrations

10-video training series from Yokogawa Test&Measurement that covers the basics of power analyzers including an overview of our power analyzers, their theory, wiring, filters and sync source, and voltage and current ranges. 


I’ve been using Yokogawa Test&Measurement instruments for power measurement and analysis for several years and they always get the job done. They provide extensive and thorough documentation for their equipment and their drivers are very handy. Features like screengrabs of test results for easier sharing and the remote interface (which minimizes the time we spend having to automate tests) have proven to be incredibly helpful. My team needs instruments that are well documented, easy to use, and reliable. Yokogawa instruments check all these boxes.

—Power Drive Systems Electrification Validation Test Development, Fortune 500 Leading Global Supplier of Sustainable Automotive Solutions


For standby power measurement and energy certification maintenance, we rely on Yokogawa Test&Measurement instruments. Their precision, accuracy, and ease-of-use are unrivaled. When given a choice between other test and measurement equipment and Yokogawa, our technicians always go for Yokogawa first. The support team provides thoughtful insights based not just on our industry but also our company’s specific needs. My team has used Yokogawa Test&Measurement instruments for decades and will continue to do so well into the future.

—Director of Technology Laboratories, International Multi-Brand Manufacturer of Major Home Appliances




    You know the basics of electrical power measurements, have set up your dyno, and made key measurements – which is great. But as your motor and drive projects progress, the complexities of system drive requirements can change frequently. Control algorithms, networked communications, and mechanical systems form a complex web of interactions that need sorting. This 60-minute webinar explains how to get past ground-level measurements and delve into comprehensive solutions that leverage test and measurement instruments including power analyzers, high-speed data acquisition, and real-time software.

    Topics include:

    • How to avoid the “gotcha's” of inverter-based measurements
    • Computations for field-oriented control
    • The integration of CAN bus communications
    • Correlations in the frequency domain
    • Other advanced motor and drive topics

    The technical presentation includes an audience Q&A.


    Why should you be concerned with your product’s power system voltage and current harmonics? From an engineering perspective, harmonics produce excessive heat in equipment that causes significant damage and results in inefficient operation. From a business perspective, compliance is an absolute requirement for entry into global markets. To minimize or eliminate these issues and establish acceptable levels of harmonics, numerous power quality standards with specifications and limits for harmonic distortion, such as IEEE 519-2014 and IEC61000-3-2, have been introduced. During this webinar, attendees will gain knowledge on the inner workings of harmonics, learn best practices for accurately measuring harmonics, learn to recognize and distinguish the critical difference between DFT and FFT, and discover important measurement tradeoffs across various test equipment.


    Although DC power measurements can be fairly straightforward, complexities with AC power measurements arise when dealing with distorted waveforms, fluctuating power factors, and multiple phases, which introduce intricacies that complicate an otherwise simple measurement process.

    This on-demand webinar provides an informative dive into the various fundamental aspects of power measurement and includes:

    • A look at multi-phase measurements and measurement techniques
    • A review of practical applications
    • Real-world examples

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