3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
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System overview
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3.1
Product description
Product description
The tried and tested SIRIUS monitoring relays for electrical and mechanical quantities
enable constant monitoring of all important characteristic quantities that provide information
about the reliability performance of the plant. Sudden disturbances and gradual changes,
which may reveal a maintenance requirement, for example, are both indicated. By means of
relay outputs, the monitoring relays enable direct shutdown of the affected sections of the
plant as well as issuing an alarm (e.g. by switching on a warning lamp). To respond flexibly
to short-term disturbances such as voltage dips or load variation, the monitoring relays have
settable delay times. This avoids unnecessary alarming and shutdowns while enhancing
plant availability.
The individual 3UG4 monitoring relays offer the following functions in various combinations:
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Undershoot and/or overshoot of liquid levels
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Phase sequence
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Phase failure, neutral failure
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Phase asymmetry
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Undershoot and/or overshoot of voltage thresholds
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Undershoot and/or overshoot of current thresholds
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Undershoot and/or overshoot of power factor thresholds
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Monitoring of the active current or apparent current
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Monitoring of the fault current
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Monitoring the insulation resistance
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Undershoot and/or overshoot of speed thresholds
The 3RT2 contactors for mounting on 3RR2 current monitoring relays offer:
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Phase sequence
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Phase failure
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Undershoot and/or overshoot of current thresholds
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Monitoring of the active current or apparent current
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Monitoring of the fault current