GE M60 Instruction Manual page 263

5 SETTINGS
• VD STALL CURRENT @ 100% V: This setting defines the locked rotor current level at the rated motor voltage (I
• VD SAFE STALL TIME @ 100% V: This setting defines the maximum time the motor is allowed to withstand the
locked rotor current at rated motor voltage (t
• VD ACCEL. INTERESECT @ 100% V: This setting defines the starting current level corresponding to the crossing
point between the acceleration thermal limit at rated voltage and the programmed relay overload curve (I
can be typically determined from the motor acceleration curves. The current value at the breakdown torque for the
100% voltage start is recommended for this setting.
The voltage dependent overload curves are shown below.
10000.00
1000.00
A
C
B
100.00
THERMAL LIMIT CURVES
FOR ABNORMAL CONDITIONS:
- LESS THAN Vmin
- MORE THAN 110%V
- LOSS OF VOLTAGE
10.00
1.00
0
GE Multilin
).
3
THERMAL MODEL CURVE
ACCELERATION INTERSECT@ minV (2)
ACCELERATION INTERSECT@ 100%V (4)
(A)
(B)
(C)
SAFE STALL POINT @ minV (1)
SAFE STALL POINT @ 100%V (3)
1 2 3
PER UNIT CURRENT
THERMAL MODEL CURVE LOCKED ROTOR LINE
100% ACCELERATE 110% ACCELERATE
100% V LINE 110% V LINE
Figure 5–55: VOLTAGE DEPENDENT OVERLOAD CURVES
M60 Motor Protection System
5.6 GROUPED ELEMENTS
ACCELERATION INTERSECT@ 110%V (6)
LOCKED ROTOR THERMAL LIMIT CURVE
SAFE STALL POINT @ 110%V (5)
4 5 6
MIN V ACCELERATE
MIN V LINE
).
3
). This value
4
5
7 8
833715A1.CDR
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