Date Code 20010719 701 Motor Protection Relay
Settings Calculation
General Data
4.5
If you connect the IN current input to the secondary of a neutral or ground current
transformer as shown in Figure 2.6 on page 2.7 in Section 2: Installation, calculate
CTRN and INTAP based on the ground CT ratings similar to the phase CT calculations
shown in the example above.
If you connect the IN input residually, as shown in Figure 2.7 on page 2.8 in
Section 2: Installation, set CTRN equal to CTR and INTAP equal to ITAP.
Phase Rotation, Nominal Frequency Settings
Table 4.3 Phase Rotation, Nom inal Frequency S ettings
The phase rotation setting tells the relay your phase labeling standard. Set
PHROT equal to ABC when B-phase current lags A-phase current by 120°. Set
PHROT equal to ACB when B-phase current leads A-phase current by 120°.
Figure 4.1 Phase Rotation Settings.
Set the FNOM setting equal to your system nominal frequency. The DATE_F
setting allows you to change the relay date presentation format to either North
American standard (Month/Day/Year) or engineering standard (Year/Month/Day). The
DMTC setting defines the thermal time constant used by the relay current and power
demand meter function, if voltages are included.
Table 4.3 Phase Rotation, Nominal Frequency Settings
Setting Prompt
Setting Range
Setting Name =
Factory Default
Phase Rotation ABC, ACB PHROT = ABC
Nominal Frequency 50, 60 Hz FNOM = 60
Date Format MDY, YMD DATE_F = MDY
Demand Meter Time Constant 5, 10, 15, 30, 60 min DMTC = 15
A
C
PHROT = ABC
A
B
PHROT = ACB
C
B
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