Allen-Bradley PowerFlex 70 Reference Manual page 41

Inertia Test
FV
Vector
[Total Inertia] is set by the inertia test. [Total Inertia] represents the time in
seconds, for the motor coupled to a load to accelerate from zero to base speed at
rated motor torque. During this test, the motor is accelerated to about 2/3 of base
motor speed. This test is performed during the Start-up mode, but can be
manually performed by setting [Inertia Autotune] to "Inertia Tune". The [Total
Inertia] and [Speed Desired BW] automatically determine the [Ki Speed Loop]
and [Kp Speed Loop] gains for the speed regulator.
Autotune Procedure for Sensorless Vector and Economizer
The purpose of Autotune is to identify the motor flux current and stator
resistance for use in Sensorless Vector Control and Economizer modes.
The user must enter motor nameplate data into the following parameters for the
Autotune procedure to obtain accurate results:
• [Motor NP Volts]
• [Motor NP Hertz]
• [Motor NP Power]
Next, the Dynamic or Static Autotune should be performed:
• Dynamic - the motor shaft will rotate during this test. The dynamic autotune
procedure determines both the stator resistance and motor flux current. The
test to identify the motor flux current requires the load to be uncoupled from
the motor to find an accurate value. If this is not possible then the static test
can be performed.
• Static - the motor shaft will not rotate during this test. The static test
determines only [IR Voltage Drop]. This test does not require the load to be
uncoupled from the motor.
The static and dynamic tests can be performed during the Start-up routine on the
LCD HIM. The tests can also be run manually by setting the value of the
[Autotune] parameter to 1 "Static Tune" or 2 "Rotate Tune".
Alternate Methods to Determine [IR Voltage Drop] & [Flux Current Ref]
If it is not possible or desirable to run the Autotune tests, there are three other
methods for the drive to determine the [IR Voltage Drop] and [Flux Current]
parameters:
• The first method is used when the motor nameplate parameters are left at
default. When the drive is initially powered up, the [Autotune] parameter is
defaulted to a value of 3 "Calculate". The values for [IR Voltage Drop] and
[Flux Current] are calculated based on the default motor nameplate data.
This is the least preferred method.
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013
Autotune
41