Rockwell Automation 20D PowerFlex 700S with Phase I Control Reference Manual - Manual (Page 127)

Rockwell Automation Publication PFLEX-RM002D-EN-E - August 2013 127
Detail Drive Configuration and Operation Chapter 1
Speed Regulator Tuning
Basic Tuning Procedure with a Gearbox or Belt
1. Identify motor and system inertia (in seconds).
The motor inertia can be determined by performing an inertia test with
the motor uncoupled from the load, or the motor inertia in seconds can be
calculated using the following formula:
where WK2 is the inertia in lbft2, RPM is the base motor speed of the
motor, and Tacc is the rated torque of the motor in lb
•
ft. Tacc can be
calculated by the following:
where HP is the nameplate horsepower of the motor and RPM is the base
motor speed of the motor.
System Inertia (parameter 9 [Total Inertia]) is determined by performing
the inertia test with the load coupled, or the value (in seconds) can be
calculated using the formulas above if WK2 is known for the system.