INSULATION RESISTANCE
MEASUREMENT TEST
This test is performed to check the insulation integrity of the circuit breaker
(i.e. insulation of the moldings, interphase barriers, and arc chutes)
- Commonly known as the Megger Test
- Values measured and documented in megohms
- Comparative analysis of values documented from one maintenance period to
the next can show insulation deterioration; this data is used to predict and
prevent circuit breaker failures
CONTACT RESISTANCE
MEASUREMENT TEST
Test used to determine the condition of the contact pole assembly and its ability
to carry current. If contacts are not maintained on a regular basis electrical
resistance due to repeated arcing and/or corrosion increases, resulting in a
significant decrease in the contact’s ability to carry current.
- Commonly known as the Ductor Test
- Contact resistance is measured from the primary connection to primary connection
and is documented in micro-ohms
- Assist in determining problems in the following areas
- Corrosion or erosion of the contact surfaces
- Construction of the contact assembly (Loose connections)
- Contaminated or lack of lubrication in the contact assembly
- Improperly adjusted contacts
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