EK
EK InstrumentsElectrical Testing Solutions
Back to Resources

Resources

Handheld Thermal Imager Buying Guide for Industrial Use

2026年04月20日

Practical buying guide focused on durability, ergonomics, and field workflow features that matter for industrial handheld thermal imagers.

Why Routine CB Testing Matters

Circuit breakers operate rarely but must function flawlessly when they do. A properly equipped circuit breaker test equipment supplier provides the instruments needed to verify operating times, contact resistance, insulation integrity, and dielectric strength — the four pillars of CB reliability.

The Four Routine Tests

  • Contact Resistance (Ductor) Test — passes 100–200 A DC through the closed pole and measures voltage drop. Healthy MV breakers read < 50 µΩ; values rising over time indicate contact erosion.
  • Operating Time / Travel Analysis — measures opening, closing, and reclose times; deviations from factory data flag mechanism wear.
  • Insulation Resistance — 5 kV megger reading between phases and to ground; values below trend line indicate moisture ingress.
  • Dielectric Withstand — applies AC or DC at the rated power-frequency level for 1 minute to confirm bulk insulation integrity.

Applicable Standards

Different regions follow different documents but the technical content overlaps:

  • IEC 62271-100 — high-voltage AC circuit breakers
  • IEEE C37.09 / C37.20.2 — North American switchgear
  • NETA MTS — Maintenance Testing Specifications, the universal field reference
  • GB 1984 — Chinese national standard for HV breakers

Equipment Categories

  • Micro-ohm meter — 100/200/600 A DC for contact resistance.
  • Timing analyser — multi-channel digital recorder with travel transducer support.
  • Insulation tester — 5 / 10 / 15 kV.
  • Hipot tester — AC up to 100 kV or DC up to 200 kV depending on equipment class.

Field Procedure

The recommended sequence on every breaker visit:

  1. Verify isolation, lock-out, and ground status.
  2. Perform "as-found" timing test.
  3. Measure contact resistance on each pole.
  4. Conduct insulation resistance sweep.
  5. Perform maintenance (cleaning, lubrication) if required.
  6. Perform "as-left" timing and resistance checks to verify improvement.

Working with a reliable industrial test equipment for export partner ensures that your field teams have the accuracy and ruggedness required for these critical utility maintenance tasks.