There are following Commissioning Tests, Diagnostic Tests and Trials of Circuit Breaker.

1) Measurement of Insulation Resistance:

Objective: To ensure that each pole of CB has sufficient Insulation Resistance with respect to Earth (i.e. CB body) and between each Pole.

 

 Test Procedure:

  1. Connect the Insulation tester
  2. It can be attended by proper allignment of Contacts or replacement of Finger contacts.

 

 Caution:

  1. During Testing, “Do not touch the Live parts”.
  2.  While connecting the Test Leads, Breaker should be in closed condition, along with Earthing, to avoid induction.
Pole Top-Earth Bottom-Earth Top-Bottom Remark
R hjk hjk hjk
Y
B

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2) Contact Resistance Measurement:

Objective: Contact resistance of the main contacts indicates wear out and misalignment of the main contacts.

 

Operating Princile: DC is injected into the main circuit and corresponding Voltage Drop is measured. The Ohm Meter operates on the four wire measurement principle.

 

Test Procedure:

  1. Provide the Earthing to the Test Kit. (Called Master Earthing in the Scope Kit)
  2. Close the Circuit Breaker.
  3. Connect the +C and +V Terminals of the Test kit to the Top Breaker Pad and -C and -V Leads of the Test Kit to Lower Breaker Pad.
  4. Keep the Range on 100 A and operate the Test Button, then keep the Range on 200 A and then again operate the Test button.
  5. Value of contact resistance is directly displayed on the digital LED display Screen.

 

Evaluation of Test Results:

  1. If the value exceeds the permissible Limits, it could result in Overheating of the Contacts.
  2. It can be attended by proper allignment of Contacts or replacement of Finger contacts.

 

 Frequency of Tests:

the main contacts indicates wear out and misalignment of the main contacts.

 

Vtg. Level (KV) CRM (μΩ) Remark
400 50
220/132/33/11  100
Current Injected (A) R Pole Y Pole B Pole
100
200