Multilin 469 Motor Management Relay ... - GE Digital Energy

Note
CHAPTER 5: SETTINGS
The 469 takes the information provided and create protection curves for any voltage
between the minimum and 100%. For values above the voltage in question, the 469
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% voltage level, the trip time of 110% will be used (see figure below).
TIME TO TRIP (SECONDS)
1000
900
800
700
600
500
400
300
200
100
90
80
70
60
50
40
30
20
10
9
8
7
6
5
4
3
2
1
HIGH INERTIA LOAD OVERLOAD CURVES
8800 HP, 13.2 kV, REACTOR COOLANT PUMP
Custom Curve
GE Multilin
Acceleration Intersect at 80%V
Acceleration Intersect at 100%V
Safe Stall Time at 80%V,
80%V Stall Current
Safe Stall Time at 100%V,
100%V Stall Current
Safe Stall Points
Extrapolated to 110%V
1 2 3 4 5 6 7 8
MULTIPLES OF FULL LOAD AMPS
806824A4.CDR
FIGURE 5–11: 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 only be one value of stall current and therefore, only one safe stall time.
5–52 469 MOTOR MANAGEMENT RELAY – INSTRUCTION MANUAL