PowerFlex Digital DC Drive User Manual -
Publication 20P-UM001C-EN-P - July 2008
Application Notes
C-5
Droop Compensation
The Droop function is used when the current must be balanced between two
drives. A typical situation is when two motors are mechanically coupled and
must run at the same speed. If, because of differences in the drive’s speed
regulators, one of the motors runs at a higher speed, it will be overloaded
and the second motor will function, essentially, as a brake.
The Droop function allows you to overcome this difference by adding a load
compensation component to the speed reference, which is proportional to
the actual load differences of the drives.
For Example:
Field Weakening Mode
Configuration (v1.006)
Important: This configuration applies only to firmware version 1.006. For
instructions on configuring a drive with firmware version 2.001
for use with an AC or DC contactor, with or without a dynamic
brake, refer to
.
The following configuration is required when operating the drive in field
weakening mode with a DC contactor and/or inverting fault device installed
in the armature circuit.
When operating the PowerFlex DC drive in field weakening mode
(parameter 469 [Field Mode Sel] set to 1 - “Field Weaken”) and using a DC
contactor and/or an inverting fault device in the armature circuit, you must
complete the appropriate installation and programming requirements
detailed below.
Master Drive
Slave Drive
[Anlg In1 Sel]
= “Speed Ref A”
[Anlg In1 Sel]
= “Speed Ref A”
[Anlg Out1 Sel] = “Torque Ref”
[Anlg In2 Sel]
= “Load Comp”
[Enable Droop] = “Enabled”
[Droop Percent] = 5%
[Droop Filter]
= 100 ms
[Droop Limit]
= 1000
!
ATTENTION: The following information is merely a guide for
proper installation. Rockwell Automation, Inc. cannot assume
responsibility for the compliance or the noncompliance to any
code, national, local or otherwise for the proper installation of
this drive or associated equipment. A hazard of personal injury
and/or equipment damage exists if codes are ignored during
installation.
