mpec SA380-IT, Руководство пользователя

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When the snapshot period elapses (default 1 hour)
When a transient spot-reading crosses an alert boundary (at any time)
Benefits
Through the balance of fast and slow scan, spot-reading and average readings the SA380-IT is able to achieve:
Rapid measurement and detection of transient earth faults.
Accurate measurement of high resistance / capacitive circuits
Stable Readings of circuits with a high resistance to earth
In addition to the above methods, the SA380-IT applies proprietary signal conditioning algorithms to improve measurement accuracy
under transient conditions, such as:
Unstable monitored circuit voltage.
Dynamic resistance to earth changes.
Transient events on monitored circuits.
2.5.2 DC Circuits Only
In a DC circuit, the Resistance to earth of each circuit leg can cause current flow from the monitored circuits supply U , through SA380-IT
s
measurement circuitry. For DC sources, such a current will always appear to flow in the same "direction" through the measurement circuit,
regardless of measurement pulse polarity.
The equivalent circuit and associated current trace are shown below:
i = Ammeter current solely due to monitored circuit voltage "bleed through" in a DC circuit.
Us
The net current flow measured by the internal ammeter is the sum of the current produced by the test pulse voltage and the current caused
by the monitored circuit voltage "bleeding through" the SA380-IT.