GLOBAL-TOOL-15 · TOOL-002 v1.0.0 · AVAILABLE

Three-phase voltage and current unbalance record

Compare three same-condition readings by their average and maximum absolute deviation. The record shows the calculation method and keeps acceptance decisions outside the tool.

Reviewed 23 July 2026
Runs in this browser
No input is stored or transmitted
Magnitude comparison—not acceptance

Three same-condition voltage or current readings flow to average, absolute deviations and maximum-deviation percentage — Decision-support diagram—not a customer installation, field measurement or limit.

Hold the comparison when

The three readings were not taken at the same point and operating state; RMS, bandwidth, waveform or VFD-output suitability is unclear; or the applicable OEM, site or authority criterion is missing.

What this tool does not decide

It does not calculate negative-sequence components, certify IEC 61000-4-30 compliance, identify root cause, or approve equipment operation, protection settings or corrective work.

Measurement inputs

Comparison result

Calculated relationship—not acceptance

Unbalance (%) = maximum |reading − average| ÷ average × 100

Voltage comparison

Average: —
Maximum deviation: —
Voltage unbalance: —

Pair	Reading	Absolute deviation

Current comparison

Average: —
Maximum deviation: —
Current unbalance: —

Phase	Reading	Absolute deviation

Interpretation boundary

Use the percentage only to compare magnitude readings. Apply an acceptance limit only after confirming the equipment, jurisdiction, site procedure, operating condition and the criterion’s own measurement method.

Field context for the print record

These fields remain in this browser and are included only if you print the page.

Equipment / asset

Measurement point

Date and time

Operating and load state

Instrument, RMS/bandwidth and clamp/probe

Waveform/VFD context, OEM criterion and notes

Primary sources and application boundary

Schneider Electric — TeSys T metering and monitoring functions: average line voltage/current and maximum percent deviation method.
Fluke — How to diagnose and fix three-phase voltage imbalance: three line-to-line readings and maximum deviation from average.

Sources reviewed 23 July 2026. They support the displayed magnitude-comparison method only. This is not a symmetrical-component calculation, a power-quality compliance instrument, or an equipment acceptance rule. Confirm the applicable country, AHJ, site permit, OEM method, qualified personnel and responsible technical review.