Rockwell Automation 1333 Drive, 3/4-5HP, 230-575V Series D - Manual (Page 54)

Operation and Programming
Chapter 5
5-11
Parameter 04 -- Volts-per-Hertz Curve
Units = Code
Range = 0/1
Factory Setting = 0
This parameter sets the shape of the volts-per-Hertz ramp, either constant
or curved.
If set to 0, the volts-per-Hertz ramp will be linear producing a constant rate
of increase from 0 to base frequency. This setting will be the setting
required for most constant torque applications.
If set to 1, the volts-per-Hertz ramp will be curved, producing a rate of
increase that will gradually curve upward as it increases from 0 to base
frequency. This setting will be required for most variable torque
applications where full rated motor torque is not required at reduced
speeds.
VoltsĆperĆHertz Curve Settings + DC Boost Settings
100%
Parameter 3
DC Boost
0%
0 Hertz
Parameter 5
Output Voltage
Output
Frequency
Parameter 4 = 0
100%
Parameter 3
DC Boost
0%
0 Hertz
Parameter 5
Output Voltage
Output
Frequency
Parameter 4 = 1
DC Boost Settings Parameter 05 -- DC Boost Select
Units = % of Output Voltage
Range = 00/40
Factory Setting = 00
This parameter adds from 0 to 40% of the drive output voltage to the motor
at low drive frequencies in 1% increments, boosting motor torque at
startup. DC boost can be added to any volts-per-Hertz curve. The optimum
DC boost setting is the lowest level that will permit satisfactory starting
torque for the motor and drive. Higher than optimum boost may produce
unnecessary motor current at low frequencies and contribute to motor
overheating. Excessive boost may even force the drive into an overcurrent
condition.