User manual

102 • vacon parameter descriptions
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1.15 TORQUE BOOST
When this parameter has been activated, the voltage to the motor changes au-
tomatically with high load torque which makes the motor produce sufficient
torque to start and run at low frequencies. The voltage increase depends on
the motor type and power. Automatic torque boost can be used in applications
with high load torque, e.g. in conveyors.
0 = Disabled
1 = Enabled
Note: In high torque - low speed applications - it is likely that the motor will
overheat. If the motor has to run a prolonged time under these conditions,
special attention must be paid to cooling the motor. Use external cooling for
the motor if the temperature tends to rise too high.
Note: The best performance can be reached by running motor identification,
see par. 1.18.
1.16 SWITCHING FREQUENCY
Motor noise can be minimised using a high switching frequency. Increasing
the switching frequency reduces the capacity of the frequency converter unit.
Switching frequency for Vacon 20: 1.5…16 kHz.
1.17 BRAKE CHOPPER
Note! An internal brake chopper is installed in three phase supply MI2 and MI3
size drives.
0 = Disable (No brake chopper used)
1 = Enable: Always (Used in Run and Stop state)
2 = Enable: Run state (Brake chopper used in Run state)
WHEN THE FREQUENCY CONVERTER IS DECELERATING THE MOTOR, THE ENERGY
STORED TO THE INERTIA OF THE MOTOR AND THE LOAD ARE FED INTO AN EX-
TERNAL BRAKE RESISTOR, IF THE BRAKE CHOPPER HAS BEEN ACTIVATED. THIS
ENABLES THE FREQUENCY CONVERTER TO DECELERATE THE LOAD WITH A
TORQUE EQUAL TO THAT OF ACCELERATION (PROVIDED THAT THE CORRECT
BRAKE RESISTOR HAS BEEN SELECTED). SEE SEPARATE BRAKE RESISTOR IN-
STALLATION MANUAL.
1.19 MOTOR IDENTIFICATION
0 = Not active
1 = Standstill identification