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CHAPTER 4: SETPOINTS
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
typically used to detect a voltage loss condition. If a voltage loss has been detected
while the motor accelerates, the thermal curve is switched to one based on the
programmed 100% voltage thermal limit:
VD STALL CURRENT @ MIN V
Range: 1.50 to 20.00 FLA in steps of 0.01
Default: 4.50 x FLA
The setting defines the locked rotor current level at minimum motor voltage (I
VD STALL TIME @ MIN V
Range: 0.1 to 1000.0 in steps of 0.1
Default: 20.0 seconds
The setting defines the maximum time that the motor is allowed to withstand the locked
rotor current at minimum motor voltage (t
VD ACCEL. INTERSECT @ MIN V
Range: 1.50 to 20.00 in steps of 0.01
Default: 4.00 x FLA
The setting defines the starting current level corresponding to the crossing point
between the acceleration thermal limit at minimum voltage and the programmed relay
overload curve (I
). This value can be typically determined from motor acceleration
2
curves. The value at the breakdown torque for the minimum voltage start is
recommended for this setting.
VD STALL CURRENT @ 100% V
Range: 1.50 to 20.00 FLA in steps of 0.01
Default: 6.00 x FLA
The setting defines the locked rotor current level at the rated motor voltage (I
VD STALL TIME @ 100% V
Range: 0.1 to 1000.0 in steps of 0.1
Default: 10.0 seconds
The setting defines the maximum time the motor is allowed to withstand the locked
rotor current at rated motor voltage (t
VD ACCEL. INTERSECT @ 100% V
Range: 1.50 to 20.00 in steps of 0.01
Default: 5.00 x FLA
The 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
). The value can be typically determined from the motor acceleration
4
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 in the
following figure.
).
1
).
3
PROTECTION
Eq. 24
).
1
).
3
4–127
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