Power Quality Analyzer Fit Tool

Overview

How to Use This Calculator

1. Enter the expected site voltage — type the voltage at the measurement point.

2. Enter the expected site current — type the current at the measurement point.

3. Select the required phase configuration — choose 1-phase or 3-phase for the job.

4. Select the required harmonic-analysis level — choose Basic, Standard, or Advanced.

5. Select the required event-capture level — choose None, Basic, Fast, or Advanced.

6. Select the required recording depth — choose Snapshot, Short-Term, or Extended.

7. Enter the selected analyzer voltage limit — type the analyzer or kit maximum voltage.

8. Enter the selected analyzer current limit — type the analyzer or CT setup maximum current.

9. Select the analyzer phase capability — choose 1-phase or 3-phase.

10. Select the analyzer harmonic, event, and recording classes — choose the available capability levels.

11. Click "Calculate" — get analyzer fit percentage, electrical headroom scores, and result status.

12. Review the result — check fit %, headroom scores, capability coverage, and status from UNDERSIZED to STRONGLY MATCHED.

All numeric inputs must be greater than zero. Phase, harmonic, event-capture, and recording class selections are required. If the analyzer phase capability does not match the required job configuration, the result is UNDERSIZED regardless of other scores.

Inputs & Outputs

Formula

Voltage_Score = Selected_Analyzer_Max_Voltage / Site_Voltage

Current_Score = Selected_Analyzer_Max_Current / Site_Current

If Analyzer_Phase_Capability >= Required_Phases:
  Phase_Score = 1
Else:
  Phase_Score = 0

If Analyzer_Harmonic_Class >= Required_Harmonic_Class:
  Harmonic_Score = 1
Else:
  Harmonic_Score = 0

If Analyzer_Event_Capture_Class >= Required_Event_Capture_Class:
  Event_Score = 1
Else:
  Event_Score = 0

If Analyzer_Recording_Class >= Required_Recording_Class:
  Recording_Score = 1
Else:
  Recording_Score = 0

Headroom_Score = min(Voltage_Score, Current_Score)

Fit_Score =
  (0.30 × Headroom_Score)
  + (0.20 × Phase_Score)
  + (0.20 × Harmonic_Score)
  + (0.15 × Event_Score)
  + (0.15 × Recording_Score)

Fit_Percent(%) = Fit_Score × 100

Key Facts

• Electrical headroom has the highest weight — 30%. If voltage or current headroom fails, the result is capped at LIMITED FIT.
• Phase mismatch means UNDERSIZED in this model, with no exception.
• Harmonic, event-capture, and recording classes act as binary pass/fail capability layers on top of electrical headroom.
• Fit above 100% means extra margin, not an error or compliance guarantee.
• Use this to screen an existing analyzer kit before a new job, or compare two analyzer profiles against the same site requirement.
• This estimator does not replace CAT rating review, probe selection, CT selection, or safe measurement procedure.
• A fit below 55%, or a phase mismatch, indicates an undersized profile regardless of other scores.
• Voltage_Score and Current_Score each equal the analyzer limit divided by the site requirement.

Applications

• First-pass check before choosing which analyzer kit to bring to a three-phase industrial site.
• Comparing two analyzer profiles against the same site voltage, current, and feature requirements.
• Screening whether an existing single-phase analyzer is adequate for a new three-phase monitoring job.
• Estimating whether a basic logger can handle a site that requires advanced harmonic analysis.
• Quick pre-job review before extended logging campaigns where recording depth matters.
• Training and educational use to understand how voltage headroom, current headroom, and capability classes combine into an overall fit estimate.

Standards & References

• IEC 61000-4-30 — Electromagnetic compatibility (EMC) — Part 4-30: Testing and measurement techniques — Power quality measurement methods — Official IEC standard defining power quality measurement methods and instrument performance classes.
• IEC 62586-1 — Power quality measurement in power supply systems — Part 1: Power quality instruments (PQI) — Official IEC standard covering power quality instrument requirements.
• IEC 62586-2 — Power quality measurement in power supply systems — Part 2: Functional tests and uncertainty requirements — Official IEC standard for PQ instrument functional testing and uncertainty.
• Fluke 1736 and 1738 Three-Phase Power Quality Loggers — Product page — Manufacturer product page showing a typical three-phase PQ logger specification for real-world reference. Practical note: IEC 61000-4-30 defines how power quality should be measured and how instruments should perform. IEC 62586-1 and 62586-2 set the instrument requirement and testing framework. Both usually require purchase. Fluke's product page is a free real-world reference for understanding what a practical three-phase PQ logger is expected to capture and record.

Common Mistakes to Avoid

• Assuming a high fit score proves the analyzer is safe to connect — it does not. Safety review is separate from this screening estimate.
• Ignoring voltage or current headroom below 1.00 — that forces the result down to LIMITED FIT at best in this model.
• Treating phase capability as optional — a phase mismatch makes the analyzer UNDERSIZED regardless of other scores.
• Thinking fit above 100% is an error — it usually means the analyzer has margin beyond the minimum stated requirement.
• Entering analyzer limits higher than the actual instrument rating — always verify against the actual product datasheet.
• Selecting a lower capability class to make the fit score look better — this undermines the purpose of the screening check.

Frequently Asked Questions