Circuit Breaker Operation Time (In-Service)

In-service testing methods First trip and Voltage Based Timing (VTM) show degradation accumulated during long idle times better than their off-service counterparts because to prepare a breaker for off-service testing, it has to be operated at least once. For the First trip test method connections are made at the trip coils and the CT’s secondary side. For the Voltage Based Timing (VTM) measurement method, the connections are made at the trip cols and the VT’s secondary side. These test methods are very well suited to detected degraded lubricants, contaminated surfaces or corroded mechanical elements.

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During a First Trip test, CIBANO measures the opening times by monitoring the CTs’ secondary current. Please note that the measured time will include the arcing time.

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CMC 430

Users of a CMC test device who also own an EnerLyzer software option, can also use their CMC for simple medium voltage circuit breaker testing. The ideal CMC test device to perform such tests is the CMC 430.


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