WT500 Mid-Range Power Analyzer

The WT500 Power Analyzer excels at single- and three-phase power measurements. Standard features include a color TFT display and USB interface for communications and memory. The instrument has a basic power accuracy of 0.1%, maximum inputs of 1000 V, 40 A and a measurement bandwidth of DC to 100 kHz.


  • Simultaneous measurement of voltage, current, power, and harmonics
  • High-speed data updating (100 ms)
  • Display of numerical values, waveforms and trends
  • Measurement of bought and sold watt hours
  • Easy setup and operation
Current range: 0.5 to 40 A
Voltage range: 15 to 1000 V
Basic Power Accuracy: 0.1%
frequency range: DC 0.5 Hz to 100 kHz

Key layout offers intuitive control

  1. Cursor Keys
    Cursor keys can be used to move the on-screen cursor in four different directions. The cursor keys and SET key can also be used for making selections in soft menus. The WT500's menu structure is even more user-friendly than other models.
  2. RANGE Keys
    The RANGE keys can be used to set the voltage and current ranges. Quick intuitive range control is available by using direct keys.
  3. DISPLAY Keys
    DISPLAY keys can be used to switch between numerical values, waveforms, and other displays. The display format can easily be changed.
  4. SETUP Key
    The SETUP key can be used to enter various settings required for power measurement such as the wiring method and filters.
  5. FILE, IMAGE, and STORE Keys
    The keys related to data storage are located in the same area. Data can be easily stored to USB memory.
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  • Simultaneous measurement of DC and AC signals
    Evaluation of DC/AC signal conversion technology is critical in the renewable energy market. With input from 2 or more elements, the WT500 can measure DC and AC signals simultaneously and calculate input-to-output efficiency.
  • Separate integration functions for charge/discharge and bought/sold power
    The WT500 is equipped with integration functions that can not only evaluate charge and discharge current such as from secondary cells, but also bought and sold power in photovoltaic power generation systems.
  • Saving measured data directly to USB memory
    Measured data can be saved in CSV format directly to USB memory.
  • Easy setup with cursor keys
    Menu-type screen offers intuitive setting.
  • Simultaneous measurement of normal data and harmonic data with the harmonic measurement, /G5 option
    RMS voltage, RMS current, power values, and harmonic components up to the 50 order can be measured simultaneously.
  • WT series for power evaluation of energy-saving equipment
    The WT series have been used as powermeters for Green IT, Energy Star, CO2 reduction and other energy-saving equipment. The WT series-Including the WT500--supports your power evaluation needs.

Newly Designed Architecture

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Intuitive control by using cursor keys in four different directions.
To reduce setting errors, menus display settings in order of relative importance in order.

Measured Value Direct Save Function

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Two USB ports for peripherals are installed for direct data saving (up to 1 G byte) in USB memory at shortest intervals.
The saved data can be opened in applications such as Excel.

* Excel is a registered trademark of Microsoft Corporation in the U.S.A.

A Variety of Display Formats

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In addition to numerical data, the WT500 can display input signal waveforms and trends (time variation of numerical data).
Bar graph display and vector display are also available with the harmonic measurement (/G5) option.

*1 Waveforms of up to approximately 5 kHz can be displayed.
*2 Excludes single-phase models.
Split screen display for numerical values and waveforms is not available.

Simple Setting and Display of Efficiency

Two efficiency calculations can be set by selecting input elements or output elements from a list. Example: η1 = PΣ/P1 x 100%
η2 = PΣ/P2 x 100%

USB Memory Storage Function

Only necessary items within the measured data like voltage, current, and power can be saved in USB memory in binary or CSV format (up to 1 GB).

Files saved in CSV format can be opened in general-purpose applications such as Excel to allow displaying of data in graphs.

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Variety of Integration Functions

In addition to integration functions of active power (WP), current (q), reactive power (WQ), and apparent power (WS), a new feature provides measurement of bought and sold watt hours. Also, average active power can be calculated over an integration interval.
This feature is useful for evaluating the power consumed by intermittent-control instruments in which the power value fluctuates. Average active power is calculated by using user-defined settings.

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GP-IB Communication (/C1)

 GP-IB communication enables you to control the WT500 or transfer data from a PC.

Ethernet Communication (/C7)

Data can be transferred via Ethernet* communication.
It enables file transfers using an FTP server.

* 100BASE-TX

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External Current Sensor Input (/EX1, /EX2, /EX3)

Current can be measured by using current clamps without disconnecting power supply wiring (voltage output type). By setting an external current sensor conversion ratio, it can support various types of current clamp-on probes.

VGA Output (/V1)

By connecting to a monitor, you can create large displays of numerical values and waveforms. This function is convenient for simultaneously confirming data on multiple monitors, or to check data remotely.

Harmonic Measurement (/G5)

This function enables simultaneous measurement of normal and harmonic data. Harmonic components of up to the 50th order can be measured. With the WT500 you can simultaneously confirm voltage, current, and the distortion factor (THD) as well as measure the distortion factor without switching modes.

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Harmonic Dual List   THD measurement

Delta Computation (/DT)

This function allows you to calculate individual phase voltages and phase currents from the line voltages and phase currents measured in a three-phase, three-wire (3P3W) system. The phase voltage can be calculated from the line voltage measured with the three-phase, three-wire (3V3A) method. This is useful when you want to determine the phase voltage in a DUT with no neutral line by using the three-phase, three-wire (3V3A) method.

Note: This function cannot be installed on products with only one element.

Added Frequency Measurement (/FQ)

In addition to the standard two channels of frequency measurement, an option is available for frequency measurement on all channels. This option provides frequency measurement of voltage and current on all channels with input elements 1 through 3 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.

Note: This function cannot be installed on products with only one input element.

Rear Panel

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Standard features

  1. Voltage input terminals
  2. Current input terminals
  3. USB communication interface
  4. External trigger Signal, External clock input Connector

Optional features

  1. External Current Sensor Input Terminals (/EX option)
  2. GP-IB communication Interface (/C1 option)
  3. Ethernet Port (/C7 option)
  4. VGA Output (/V1 option)


Example of basic characteristics showing the WT500's high precision

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Connection Diagram

Connection for the Measurement Cables and Adapters

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Product Part no.  Specifications Order quantity
Output connector B8200JQ D-SUB 9-pin, with 2 screws 1
Load resistors B8200JR   10 Ω, 0.25 W x 4
Connect 4 in parallel to set resistance to 2.5 Ω.   

Connection Diagram for Clamp-on Probe

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*Don't connect and use the current input terminal and EXT terminal simultaneously.

CT60/CT200/CT1000/CT2000A AC/DC Current Sensor

AC/DC current sensors capable of highly accurate measurement starting in DC range.

B9284LK External Sensor Cable

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

96001/751552 Current Clamp-On Probe

Special AC-Input Clamp-on Probes for Large-current Hot Line Measurement

751512 Banana (Male) to Binding Post Adapter

Safety-terminal-binding-post adapter. Use for circuits having voltage levels no greater than 42 V.

758917 DMM Measurement Lead Set

A set of 0.8m long red and black test leads, used in combination with a pair of optional 758922 or 758929 alligator-clip adapters.

758921 Fork terminal adapter

Adapters for fitting a 4mm banana plug to a fork terminal. Set contains one black and one red clip. 1000 Vrms-CAT II.

758922 Small Alligator-Clip Adapter 300V

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

758923 Spring Hold Safety Terminal Adapter Set

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

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

Rated at 1000V. Attaches to the 758917 test leads. Sold in pairs.

758931 Screw-Fastened Safety Voltage Terminal Adapter Set

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

701959 Safety mini clip (hook type)

Set contains one black and one red clip. 1000 Vrms-CAT II.

751533-E4 Rack mounting kit

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

751533-J4 Rack mounting kit

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

751534-E4 Rack mounting kit

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

751534-J4 Rack mounting kit

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


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Check for differences in the specifications or features of the instruments. For values that do not match when inputting a 50/60 sine wave Check whether the value is within the specifications (error) of each power ...
The WT3000 D/A output terminal is electrically isolated from the case. For all other models, the D/A output terminal is connected to the case.
The difference in measurement values can be attributed to the difference in calculation methods for normal mode and harmonic mode.   The voltage, current, and power in normal mode are displayed as the total of the ...
The peak value and crest factor may be unstable if they have not been captured accurately. If the peak value is not stable, neither will the crest factor be stable. The cause is the difficulty in capturing the narrow ...
In the three-phase three-wire, or 3V3A wiring scheme, the phase angle of voltage and current input to each input differs from that of the actual load because it is the line to line voltage that is measured.  In ...
 In the case of three-phase three-wire, or 3V3A wiring, the power, power factor, and phase angle of each input element do not match because it is the line to line voltage that is measured.   Please download and refer ...
Check for differences in the specifications or features of the instruments. For values that do not match when inputting a 50/60 sine wave Check whether the value is within the specifications (error) of each power ...
The measurement intervals of the measured I/O data must overlap exactly. Check the sync source setting. For example, route the input to a three-phase device under measurement to input elements 1-3 on the power meter, ...
The value depends on the model of the power analyzer. For WT1000, WT2000, WT100, and WT200, it is fixed to the fundamental wave. For power analyzers with 7 segments LED, the relative harmonic content is fixed to the ...
The actual display update rate for the WT500 will depend on the input signal and the trigger setting. In addition, there may be a very small trigger delay (several milliseconds) if the input signal does not match the ...
Check the Synch Source and Frequency Filter settings When a single-phase signal being measured fluctuates around power factor of 1.Slight fluctuations in the measured values of voltage, current, and power can cause a ...
The following may be causing the problem. 5V may have occurred during rating. Check the range setting again. DA output error can affect the values when the input is smaller than the rating. Have you checked the error ...
The input terminals on all Yokogawa power meteras are located on the rear panel. This takes into account safety when handling the measuring instrument.    The signal input to the power meter normally carries high ...
To use USB interface on the WT500 and WT1800 from NI LabVIEW environment, you will need to use the USB driver from National Instruments. This USB driver is usually installed when you install NI-VISA and is called the ...
When the WT1600 is set into Integration mode, the averaged power (watt) values can be calculated and displayed. This is available only by using the User-Defined Function feature found in the MEASURE button menu.  The ...
 You can not use LabVIEW and WTviewer to communicate with the PC using same USB driver. The USB driver for LabVIEW and the USB driver for WTviewer is different. Yokogawa's YKMUSB driver is used by WTviewer ...
There are several items you will need to check and verify to solve this issue. Verify the GP-IB connectionSome instruments have a D/A output connector located next to the GP-IB connector. There have been some ...

The Power Analyzer Accuracy and Basic Uncertainty Calculator can be used to determine the uncertainty in voltage, current, and active power (watts) measurement values for various frequency ranges and wiring systems.

Check the "Sync Source" and zero cross filter (frequency filter) settings. For the WT3000, "Sync Source" setting is irrelevant if the data update rate is 250 ms, 500 ms, 1 s, or 2 s. Sync Source SettingIn principle, if ...
The waveform may actually not be a pure sine wave. Even though a 50/60 Hz sine wave is expected, the following factors may be involved: The waveform is slightly distorted (harmonic components are mixed in) Small ...
This is to prevent an open current circuit. Among non-Japanese power meters, there are products that also use safety terminals for current terminals. Safety terminals can be said to be safe because the terminal is not ...
The WTViewer Save Setting feature will only save the setting information of the WTViewer. The Save Setting feature will NOT save the setting information of the instrument. The saved file for the WT500, WT1800 or ...
The AC Power Input in all Yokogawa instruments is designed as a 3-pin connection (one of which is a GND pin). In some parts of the world, PCs are sold with AC power cables that are 2-pin. Often times this means the ...
THE WT1800 and WT500 STORE function can only be used to record NUMERIC data.   The WT1600 and WT3000 STORE function can be used to record both NUMERIC and WAVEFORM data.
The part numbers for the black current knobs and pads (studder) is listed below: A9105ZG: Black Current Knob Set of 2 B9292GX: Pad (Studder) Set of 10
Although WTViewer is not officially supported under the Linux environment, users have successfully done so using WINE (flavor of Linux) via RS232. For connectivity to WT210/WT230, WTViewer requires that the meter be set ...
Yes, please contact your nearest Yokogawa representative for more details.
The following product tutorial guides have been created for the WT and PZ Series Power Meter and Analyzer instruments and are available for download. Each tutorial contains quick and easy steps to help you get started ...

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This article outlines the top reasons for inaccuracies in power measurements and how to tackle them.

Download the article to learn about:   

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