Timing and motion tests provide a baseline for the installed breaker. Their value depends on correct definitions, sensor setup, control voltage and breaker-specific limits.

Learning objectives

Configure analyser channels, obtain repeatable traces and separate mechanism problems from measurement error.

Core engineering principles

Time definitions must be written

Opening, closing, contact separation and make intervals use different endpoints.

All poles are recorded

Average values can hide one slow pole or excessive spread.

Motion transducer setup is breaker-specific

Mounting point, direction and scaling determine travel and velocity accuracy.

Control voltage affects time

Trip and close terminal voltage should be measured, particularly at acceptance limits.

Manufacturer limits govern

Generic timing values are not valid acceptance criteria for every model.

Engineering application method

  1. Step 1: Confirm breaker condition and analyser calibration.
  2. Step 2: Connect command, main-contact and auxiliary channels.
  3. Step 3: Record control voltage and timing for all poles.
  4. Step 4: Add travel/velocity where required.
  5. Step 5: Compare with manufacturer limits and save baseline traces.

Practical example

A slow pole can be caused by mechanism friction or a wrongly configured analyser threshold. Repeating with verified channel setup prevents false diagnosis.

Common mistakes

  • Reporting only average time.
  • Mixing opening and breaking time.
  • Using an unvalidated transducer point.
  • Ignoring coil voltage.
  • Applying another model’s limits.

Design and review checklist

  • Are definitions explicit?
  • Are all poles recorded?
  • Is setup repeatable?
  • Is control voltage known?
  • Are traces archived?

Standards basis and official sources

Engineering note: Verify the contracted standard edition, amendments, manufacturer evidence and project-specific studies before applying these principles to a supplied assembly.

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