Firmware Manual

Appendix A—Description of Parameters
156 PowerXL DG1 Series Adjustable Frequency Drives MN040004EN—March 2014 www.eaton.com
P8.3 109 V/Hz optimization 1, 2, 3, 4 RW
Automatic torque boost
The voltage to the motor changes automatically, 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
where starting torque due to starting friction is high, e.g., in conveyors.
Example:
What changes are required to start the load from 0 Hz?
First set the motor nominal values (Parameter group P1.1).
Option 1: Activate the Automatic torque boost.
Option 2: Programmable V/Hz curve.
To obtain the required torque, the zero point voltage and midpoint voltage/frequency
(in parameter group P1.8) need to be set, so that the motor can draw enough current
at the low frequencies. First set parameter P1.8.3 to Programmable V/Hz curve
(value 2).
Increase the zero point voltage P1.8.8 to get enough current at zero speed. Then set
the midpoint voltage P1.8.7 to 1.4142*P1.8.8 and the midpoint frequency P1.8.6 to
value P1.8.8/100%*P1.1.10.
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.
Code Modbus ID Parameter Application
RO/RW