Description
2.7 Electronic trip unit
3VA molded case circuit breakers with UL and IEC certification
Manual, 01/2019, L1V30435333-01
95
2.7.7
Measuring with a Rogowski coil
The Rogowski coil is a toroidal coil without a ferromagnetic core. It is used as a component
in electronic measuring devices to measure alternating current.
Advantages of the current sensor:
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Each transformer can be optimized for its task and operating points
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Transformers for power generation
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Transformers for measurement
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Higher accuracy of current measurement and therefore higher accuracy for ground-fault
currents
A power measurement is made possible by the more exact and more linear measurement of
the current together with the integrated voltage tap in the molded case circuit breaker.
Accuracy levels of the specified measured values of the 8-series ETU, including the
integrated current sensors
Interpretation of measured values
PF
Power factor
Measured current and voltage values are always positive.
The "normal" direction of energy flow of the 3VA UL molded case circuit breaker is from top
(terminals 1, 3, 5) to bottom (terminals 2, 4, 6), which corresponds to operation in quadrants
Q1 and Q4. If the molded case circuit breaker is supplied from below (terminals 2, 4, 6), it
operates in quadrants Q2 and Q3, and the measurement direction can be adjusted using the
powerconfig software.
