GE 489 Instruction Manual page 112

4.10 S9 THERMAL MODEL
To illustrate the Voltage Dependent Overload Curve feature, the thermal limits shown in Figure 4–13: Thermal Limits for
High Inertial Load on page 4–61 will be used.
1. Construct a custom curve for the running overload thermal limit. If the curve does not extend to the acceleration ther-
mal limits, extend it such that the curve intersects the acceleration thermal limit curves. (see CUSTOM CURVE below).
2. Enter the per unit current value for the acceleration overload curve intersect with the custom curve for 80% voltage.
Also enter the per unit current and safe stall protection time for 80% voltage (see ACCELERATION CURVE below).
3. Enter the per unit current value for the acceleration overload curve intersect with the custom curve for 100% voltage.
Also enter the per unit current and safe stall protection time for 100% voltage (see ACCELERATION CURVE below)
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MULTIPLES OF FULL LOAD AMPS
808827A3.CDR
Figure 4–14: VOLTAGE DEPENDENT OVERLOAD CURVES
489 Generator Management Relay
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4 SETPOINTS
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489 Custom Curve
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808828A3.CDR
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