ABB A43 User Manual page 87

Measurement Methods
Illustration The following illustration shows a direct connected single phase meter measuring
the active energy (E) consumed by a load.
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1-element metering in a 4-wire system
In 4-wire system the single element metering method only gives correct results
in a balanced system (same voltage, current and power factor in all phases).
This method should not be used for accurate measurement, but can be used
when high accuracy is not needed.
Illustration The following illustration shows single phase metering in a 3-phase system.
L1
L2
L3
2CMC48001M0201
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Meter
Meter
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Load
Load
A43/A44
User Manual