GE 489 Instruction Manual page 97
Generator management relay
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Also See for 489:
- Instruction manual (314 pages) ,
- Communications manual (78 pages) ,
- Instruction manual (259 pages)
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4 SETPOINT PROGRAMMING
The 489 takes the information provided and create protection curves for any voltage between the minimum and 100%. For
values above the voltage in question, the 489 extrapolates the safe stall protection curve to 110% voltage. This current
level is calculated by taking the locked rotor current at 100% voltage and multiplying by 1.10. For trip times above the 110%
current level, the trip time of 110% will be used (see the figure below).
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Figure 4–15: VOLTAGE DEPENDENT OVERLOAD PROTECTION CURVES
The safe stall curve is in reality a series of safe stall points for different voltages. For a given voltage, there can be
only one value of stall current, and therefore only one safe stall time.
NOTE
GE Power Management
GE Power Management
Custom Curve
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MULTIPLES OF FULL LOAD AMPS
489 Generator Management Relay
4.10 S9 THERMAL MODEL
489
VOLTAGE DEPENDENT OVERLOAD
PROTECTION CURVES
Acceleration Intersect @ 80%V
Acceleration Intersect @ 100%V
Safe Stall T ime @ 80%V,
80%V Stall Current
Safe Stall T ime @ 100%V,
100%V Stall Current
Safe Stall Points
Extrapolated to 1 1 0%V
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808831A2.CDR
4
8
4-59
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