Manual 37351A
MFR 11 Packages - Protection Relay
© Woodward
Page 7/59
Measurement Value Logging
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Voltage
Voltage is displayed as three-phase r.m.s measurement of the phase-neutral and/or phase-phase voltages.
Package
SC
utilizes single-phase r.m.s. measurement of the synchronizing voltage V
L1-L2
.
This device can be ordered with the following measuring voltage input ranges (rated voltages). Please indi-
cate the measuring voltage input required when ordering (refer to Technical Data on page 48):
•
66 V/115 V ....................[1]
•
230 V/400 V ....................[4]
•
400 V/690 V ....................[7]
Frequency
Frequency measurement is extracted from the digitally filtered measuring voltages. The frequency is meas-
ured three-phase if the measured voltage exceeds 15% of the nominal voltage. This ensures rapid and precise
measurement of the frequency. However the frequency is still measured correctly even if voltage is only ap-
plied to one phase.
