GE M60 Instruction Manual page 301

CHAPTER 5: SETTINGS
VD SAFE STALL TIME @ 100% V
current at rated motor voltage (t
VD ACCEL. INTERESECT @ 100% V
between the acceleration thermal limit at rated voltage and the programmed relay overload curve (I
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 figure shows the voltage dependent overload curves.
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
M60 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
— This setting defines the maximum time the motor is allowed to withstand the locked rotor
).
3
— This setting defines the starting current level corresponding to the crossing point
Figure 5-84: Voltage dependent overload curves
THERMAL MODEL CURVE
ACCELERATION INTERSECT@ minV (2)
ACCELERATION INTERSECT@ 100%V (4)
(A)
(B)
(C)
SAFE STALL POINT @ minV (1)
1 2 3
PER UNIT CURRENT
THERMAL MODEL CURVE LOCKED ROTOR LINE
100% ACCELERATE 110% ACCELERATE
100% V LINE 110% V LINE
ACCELERATION INTERSECT@ 110%V (6)
LOCKED ROTOR THERMAL LIMIT CURVE
SAFE STALL POINT @ 100%V (3)
SAFE STALL POINT @ 110%V (5)
4 5 6
MIN V ACCELERATE
MIN V LINE
GROUPED ELEMENTS
). This value can be
4
7 8
833715A1.CDR
5-173
5