GE M60 Instruction Manual page 299

CHAPTER 5: SETTINGS
1000
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Voltage dependent overload functionality is operational only if the selected
menu is assigned to a valid three-phase VT.
 MOTOR SETUP
NOTE
In this instance, each distinct portion of the thermal limit curve must be known and protection coordinated against the
curve. The relay protecting the motor must be able to distinguish between a locked rotor condition (curve 4) and an
accelerating condition for different levels of the system voltage (curves 2 and 3). Voltage is continually monitored during
motor starting and the acceleration thermal limit portion of the relay overload curve is dynamically adjusted based on
motor voltage variations.
M60 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
Figure 5-82: Thermal limit curve for high inertia
HIGH INERTIA LOAD OVERLOAD CURVES
8800 HP, 13.2 kV, REACTOR COOLANT PUMP
1
2
9
8
7
6
5
4
3
2
1
1 2 3
MULTIPLES OF FULL LOAD AMPS
GE Multilin
1- Running Overload Thermal Limit
2- Acceleration Thermal Limit at 80%V
3- Acceleration Thermal Limit at 100%V
4- Locked Rotor Thermal Limit
5- Motor Acceleration Curve at 80% V
6- Motor Acceleration Curve at 100%V
3
4
5
6
4 5 6 7
806821A4.CDR
MOTOR LINE SOURCE
GROUPED ELEMENTS
8
in the
SYSTEM
5-171
5