Testing and checking of switches

What you can try

Main Circuit

Operating mechanism

Auxiliary circuit

Types of tests (application)

Time measurement

Definitions (IEC 62271-100):

Definitions (IEC 62271-100): 3.7.136

Main contact operating time measurement

  1. Conventional method
    (one side connected to ground)
  2. Both sides grounded (BSG) method:
  3. a) Tank under voltage circuit breaker
  4. b) Dead tank circuit breakers
  5. c) GIS circuit breakers


Both sides grounded on AIS (live tank)

IEEE Standard 510-1983 "IEEE Recommended Practices for High Voltage and High Power Test Safety"

IEEE Standard 510-1983.

Main contact wire connection for BSG for AIS circuit breakers

Both sides Grounding timing on the dead tank circuit breaker

Both sides grounded in GIS (gas insulated substation) CB

Contact resistance (static)


The higher the current, the higher the accuracy, contamination and oxidation of the contact surface

According to the standard, a test current as close as possible to the rated current

is recommended.

Both sides grounded

Safety reasons

Current clamp

Dynamic resistance measurement

DRM - measuring principle

MilliOhms arc pair contacts

Full DRM test

Contact voltage drop and motion measurements allow calculation of arcing contact sweep

Case Study 1 - DRM Test

Comparison of DRM results (resistance increase - change in resistance curve)

Case study 2

After disassembly, the length of the contacts was measured with a caliper and compared with the results of the DRM, and confirmed with the results obtained with the CAT device.

Testing of the operating mechanism

Examples of transducer mounting:

Motion and velocity measurement - graphical analysis

Motor load time and current Parameters:

It can be used to evaluate:

Auxiliary circuit

Measure the coil resistance

Minimum trigger voltage

Minimum operating voltages of the coils:

International and national standards such as IEC 56, IEEE C37.09, etc.

"Test" First trip