Overview

The UNI-T UTE323 three-phase digital power meter delivers precision measurement across an industry-leading 300 kHz bandwidth with ±0.1% accuracy. Featuring a vivid 5-inch TFT display with integrated waveform visualization, 300 kSa/s sampling, and IEC 61000-4-7 compliant harmonic analysis, this instrument provides the comprehensive measurement capabilities that power electronics engineers demand for development, certification testing, and production validation.

Engineered for professional testing environments, the UTE323 combines three independent measurement channels with real-time math functions, automated pass/fail comparators, and versatile connectivity via USB, LAN, and RS-232. The exceptional bandwidth captures high-frequency switching transients that 100 kHz competitive instruments miss, while the intuitive display eliminates the constant menu navigation required with 7-segment displays. Whether characterizing motor drives, validating power supply efficiency, or performing IEC compliance testing, the UTE323 delivers measurement clarity and workflow efficiency that accelerates your development cycle.

The UTE323's 5-inch full-color TFT display (800×480 resolution) represents a fundamental advantage over competitive power meters using 7-segment displays. Where 7-segment instruments force you to cycle through parameters one at a time—pressing buttons repeatedly to find the measurement you need—the UTE323 presents all critical parameters simultaneously on a single screen.

This simultaneous viewing capability transforms your workflow. Monitor voltage, current, power, apparent power, reactive power, power factor, frequency, and integrated energy all at once. When running efficiency tests, watch input power, output power, and calculated efficiency update together in real time. During harmonic compliance testing, view THD alongside fundamental power and frequency without menu navigation.

The graphical interface uses color coding and logical grouping to make data interpretation immediate. You spend your time analyzing results rather than hunting for measurements. For engineers who run multiple test types daily, this interface efficiency compounds into significant time savings and reduced operator frustration.

This is a significant competitive advantage: the UTE323 provides oscilloscope-like waveform visualization that competitive 7-segment power meters completely lack. Where competitors provide only numeric measurements, the UTE323 simultaneously displays voltage and current waveforms in real time, revealing signal characteristics that numbers alone cannot convey.

The waveform display enables visual identification of phase relationships between voltage and current—instantly see whether your load is inductive or capacitive. Observe harmonic distortion as actual waveform deformation rather than abstract THD percentages. Identify switching artifacts from PWM drives, commutation spikes from motor controllers, and clipping in power amplifiers. Verify that power factor correction circuits are properly shifting current phase. Diagnose rectifier bridge failures by observing asymmetric waveforms.

For many power analysis tasks, this waveform capability eliminates the need to connect a separate oscilloscope. Set up once with the UTE323 instead of running multiple test cables and synchronizing separate instruments. Engineers consistently report that waveform visualization accelerates troubleshooting by making problems visually obvious that would require extensive analysis from numeric data alone.

The UTE323's 300 kSa/s sampling rate provides three times the sampling density of standard 100 kSa/s power meters, directly improving measurement fidelity during transient events. This high sample rate captures the fine temporal detail of startup inrush currents, switching transients, and load step responses that lower-speed instruments miss or misrepresent through aliasing.

Consider motor startup: inrush current can spike to 8× running current over just a few milliseconds. With 300 kSa/s sampling, the UTE323 captures hundreds of samples during this critical period, accurately measuring peak current and energy consumption. A 100 kSa/s instrument might capture only 10-20 samples of the same event, potentially missing the actual peak or averaging away important detail.

For switching power supplies operating at 100+ kHz, the high sample rate ensures each switching cycle is properly sampled according to Nyquist criteria. This prevents aliasing artifacts that would corrupt harmonic measurements and power calculations. The dense sample spacing also improves the accuracy of integrated energy measurements by capturing rapid power fluctuations that coarser sampling would smooth over.

In automated test systems, higher sample rates reduce the update interval needed to achieve measurement stability, increasing production throughput. The combination of 300 kHz bandwidth and 300 kSa/s sampling ensures the UTE323 faithfully represents your signals from DC through high-frequency switching transients.

The UTE323's 300 kHz bandwidth provides coverage three times wider than competitive instruments typically offering 100 kHz bandwidth. This expanded frequency range directly impacts measurement capability and accuracy for modern switching power electronics.

Consider harmonic measurement at a 10 kHz fundamental frequency (common for high-speed motor drives and switch-mode power supplies). The UTE323's 300 kHz bandwidth enables accurate measurement through the 30th harmonic, while a 100 kHz instrument stops at approximately the 10th harmonic. Those missing higher-order harmonics contain real power and contribute to total harmonic distortion—measurements that 100 kHz instruments simply cannot capture.

For compliance testing against IEC 61000-3-2 or IEEE 519, standards specify harmonic limits through the 40th or 50th order. A 100 kHz bandwidth physically cannot measure compliance for any system operating above 2-2.5 kHz fundamental frequency. The UTE323's 300 kHz bandwidth extends useful harmonic analysis to 6 kHz fundamentals, covering the vast majority of industrial and commercial equipment.

Modern power converters increasingly use SiC and GaN devices switching at 20 kHz and higher to reduce magnetic component size. Characterizing these designs requires bandwidth that extends well beyond the fundamental frequency to capture switching harmonics and EMI signatures. The UTE323's 300 kHz bandwidth future-proofs your test capability as switching frequencies continue to increase.

This bandwidth advantage isn't just about measuring faster signals—it's about measuring complete signals. Higher harmonics contain energy that contributes to RMS current, power loss, and heating. Without adequate bandwidth, you're making incomplete measurements that underestimate current stress, power dissipation, and compliance violations.

The UTE323 implements IEC 61000-4-7:2002 compliant harmonic measurement methodology, ensuring your pre-qualification results match the methods certification laboratories will use for official testing. This compliance encompasses the complete measurement chain: PLL-based synchronization, rectangular windowing, grouping methods, and FFT calculation parameters specified by the standard.

The power meter analyzes harmonics through the 50th order, covering the full range required by IEC 61000-3-2 (harmonic current emission limits) and IEC 61000-3-3 (voltage fluctuation limits). For each harmonic, the UTE323 reports magnitude, phase angle, and percentage relative to fundamental, presented in both tabular format and graphical bar charts that make compliance verification immediate.

Harmonic measurement supports both conventional mode (fixed 1024-point FFT) and IEC mode (200 ms time window for 50/60 Hz systems). The IEC mode implements the precise measurement windows and grouping algorithms that certification labs use, ensuring your measurements correlate directly with official test results. This correlation is critical—catching compliance failures in-house costs hours of engineering time, while discovering them during official certification costs weeks and thousands of dollars in retest fees.

Beyond compliance testing, harmonic analysis supports filter design, EMI troubleshooting, and power quality investigation. The waveform display complements numeric harmonic data by showing visually how harmonics distort the time-domain signal, providing intuitive insight into harmonic content and its effects.

Beyond instantaneous power measurement, the UTE323 integrates power over time to measure energy consumption (Wh, Wh+, Wh-) and charge flow (Ah, Ah+, Ah-). This integration function is essential for efficiency testing, standby power measurement, and battery characterization. The power meter supports three integration modes—manual, standard, and repetitive—to match different test protocols.

The integration function runs continuously for up to 10,000 hours, making it suitable for long-term monitoring and lifetime testing. Set a timer to automatically stop integration after a specified period, or run continuously until you manually stop it. The large integration capacity (±999,999 MWh) accommodates both milliwatt standby measurements and kilowatt continuous operation without overflow concerns.

For Energy Star testing, measure standby power by integrating over the required 24-hour test period, then divide integrated energy by time to get average standby power. For battery testing, track amp-hours during charge/discharge cycles to verify capacity. For production testing, integrate energy during a standard test cycle and compare against limits to verify efficiency compliance.

Here's a common frustration: you're measuring input power on channels 1-3 and output power on an external meter. To calculate efficiency, you typically need to export both measurements to a spreadsheet, align the timestamps, divide output by input, multiply by 100, and plot the results. If you're sweeping across 20 load points, that's 20 manual calculations—and if you spot an issue and need to re-run the test, you do it all again.

The UTE323's built-in math functions eliminate this workflow. Configure a math channel to automatically calculate efficiency as (Pout)/(P1+P2+P3)×100, and the result updates in real time on the display alongside your raw measurements. The power meter supports six mathematical operations:

• A+B: Sum powers for total system input or multi-channel totalization
• A-B: Calculate losses (input minus output) or power differentials
• A×B: Scale measurements or calculate products (e.g., power × time for energy)
• A/B: Efficiency calculations (Pout/Pin), cost per watt ($/W), power factor ratios
• A²/B: Power density (Power²/Volume) for thermal calculations
• A/B²: Specialized ratios for power electronics analysis

Math results appear as live measurements that update with your data acquisition rate. You can output them via D/A channels for real-time monitoring, log them to USB along with raw measurements, or send them via remote commands for automated test sequences. This transforms efficiency testing from a post-processing exercise into real-time feedback that lets you optimize your design during the test rather than hours later after analyzing spreadsheets.

Production testing has a fundamental problem: operators need instant pass/fail decisions, but power measurements involve multiple parameters—voltage, current, power, power factor, efficiency, harmonics. An operator can't mentally check whether all six parameters simultaneously fall within specification limits while maintaining production throughput.

The UTE323's comparator function solves this by implementing automated go/no-go testing. Define upper and lower limits for any measured parameter—say, efficiency must be 88-92%, power factor must exceed 0.95, and THD must stay below 5%. The power meter continuously evaluates all active comparator conditions and displays clear PASS or FAIL status. Connect the comparator output to your test fixture's indicator lights or automated handling system, and you've eliminated operator interpretation errors.

For production environments, this means:

• Consistent test criteria across all operators and shifts
• Instant visual feedback reduces test time per unit
• Automated sorting of passing and failing units
• Digital output signals for integration with conveyor systems and MES
• Documentation of test limits in saved configurations

The comparator configuration saves with your measurement setup, ensuring every test applies identical acceptance criteria. This consistency is essential for quality control, especially when validating that contract manufacturers meet your specifications.

Long-term reliability testing creates a time-bind: you need to monitor equipment over hours, days, or weeks, but you can't dedicate lab space and engineering time to watching measurements continuously. Many engineers resort to writing custom data acquisition scripts, setting up separate DAQ systems, or manually recording measurements at intervals—all of which consume time better spent on analysis rather than data collection.

The UTE323's USB data logging provides autonomous measurement recording. Insert a USB flash drive, configure the logging interval and parameters, start the test, and walk away. The power meter records all selected measurements—voltage, current, power, harmonics, efficiency calculations, integrated energy—directly to CSV files that open in any spreadsheet application.

Practical applications include:

• Burn-in Testing: Monitor power consumption and efficiency over 48-hour product burn-in cycles
• Temperature Cycling: Record power parameters as equipment cycles through environmental chamber profiles
• Standby Power Verification: Measure average standby power over 24-hour periods as required by Energy Star
• Load Profile Recording: Capture power consumption patterns of equipment under realistic operating cycles
• Drift Testing: Monitor long-term parameter stability to verify calibration intervals

The logged data includes timestamps, making it straightforward to correlate power measurements with other test conditions or events. This unattended capability multiplies your lab's effective capacity—one engineer can supervise multiple long-term tests simultaneously rather than being tied to a single measurement station.

Every test has different measurement priorities. When characterizing startup behavior, you care about peak voltage and inrush current. During efficiency mapping, you need input power, output power, and the calculated ratio. For harmonic compliance, THD and individual harmonic magnitudes matter most. Constantly navigating menus to access the parameters relevant to your current test wastes time and breaks concentration.

The UTE323 allows you to create custom display configurations tailored to specific test types. Set up a "Motor Efficiency" screen showing three-phase input power, mechanical output, calculated efficiency, and power factor. Create a "Harmonic Compliance" layout with THD, individual harmonic bar charts, and IEC 61000 comparison results. Configure a "Production Test" display with large PASS/FAIL indicators and the six critical parameters your test procedure requires.

Save these configurations and recall them instantly when switching between test types. The power meter stores setup parameters including measurement ranges, integration settings, math functions, comparator limits, and communication configuration—everything needed to replicate a test exactly. This capability supports several important workflows:

• Standardized Test Procedures: Ensure all engineers run identical tests by loading the validated configuration
• Quick Test Switching: Move between efficiency, harmonics, and inrush testing without manual reconfiguration
• Training Simplification: New engineers load proven configurations rather than learning complex setup procedures
• Multi-Shift Consistency: Production test configurations eliminate shift-to-shift variation

For labs running diverse tests on different product types, saved configurations transform the power meter from a general-purpose instrument requiring setup before each test into a collection of specialized test stations optimized for specific measurements.

Configured with 12 D/A output channels, the UTE323 can proportionally scale and output parameters such as voltage, current, and power from each measurement unit. Each channel provides ±5V full-scale output (±7.5V maximum) with 16-bit resolution, suitable for driving strip chart recorders, data acquisition systems, or process control equipment.

D/A outputs enable several critical workflows:

• Historical Recording: Connect to strip chart recorders for permanent paper documentation of long-term tests
• External Data Acquisition: Feed power measurements to multi-channel DAQ systems alongside temperature, vibration, and other sensor data
• Process Control Integration: Use power measurements as feedback signals for automated test systems and closed-loop control
• Real-Time Monitoring: Display critical parameters on external meters or indicators visible across the lab
• Math Function Output: Output calculated values like efficiency or losses for external analysis or control

The D/A update interval matches your selected data acquisition rate, ensuring analog outputs track measurements in real time. This capability is particularly valuable in automated test systems where multiple instruments must synchronize, or in production environments where operators monitor analog gauges for immediate visual feedback.

The UTE323 provides comprehensive connectivity for both manual remote control and automated test integration. Standard interfaces include:

• LAN (Ethernet): 10/100/1000 Base-T connection supports VXI-11, raw socket, and web browser control
• USB Device: Direct connection to PC for remote control via USB-TMC protocol
• USB Host: Front-panel port accepts flash drives for data logging and firmware updates
• RS-232: Standard serial interface for legacy systems and point-to-point connections

Both SCPI (Standard Commands for Programmable Instruments) and Modbus protocols are supported, enabling integration with test automation frameworks, PLCs, and SCADA systems. SCPI commands provide comprehensive control over measurement configuration, data retrieval, and instrument settings. Modbus RTU and Modbus TCP variants support industrial automation environments.

For rapid automation development, UNI-T provides PC software supporting drag-and-drop test sequence creation, real-time data visualization, and report generation. Python, LabVIEW, and C++ programming examples are available to accelerate custom automation development.

The UTE323's measurement capabilities directly support compliance testing against major international power quality and energy efficiency standards. The IEC 61000-4-7 compliant harmonic measurement methodology ensures your pre-qualification results match certification laboratory methods, while the high accuracy and broad bandwidth enable precise verification across multiple regulatory requirements.

International Power Quality Standards

• IEC 61000-4-7: Compliant harmonic and interharmonic measurement methodology through 50th order
• IEC 61000-3-2: Harmonic current emission limits verification for equipment drawing up to 16A per phase
• IEC 61000-3-3: Voltage changes, voltage fluctuations, and flicker limits assessment
• IEEE 519: Harmonic control in electrical power systems—measure THD and individual harmonic limits

Energy Efficiency Standards

• Energy Star: Measure active mode efficiency at specified load points and standby power consumption
• IEC 60034-2-1: Motor efficiency testing for IE1, IE2, IE3, and IE4 classification
• IEC 61557: Electrical safety testing requirements for low-voltage distribution systems
• 80 PLUS Certification: Power supply efficiency testing at 20%, 50%, and 100% load conditions

Grid Connection and Renewable Energy Standards

• IEEE 1547: Distributed energy resource interconnection—power quality and harmonic injection limits
• IEC 61727: Photovoltaic system utility interface characteristics verification
• UL 1741: Inverter, converter, and controller interconnection equipment testing