Rockwell Automation 20P PowerFlex Digital DC Drive - Manual (Page 271)

Rockwell Automation Publication 20P-UM001I-EN-P - February 2013 271
Application Notes Appendix C
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 drives 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 (see the block diagram for Droop Compensation - Inertia / Loss
Compensation on page
322 for more information):
Field Weakening Mode
Configuration (v1.006)
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” (Par 14) [Anlg In2 Sel] = “Load Comp” (Par 698)
[Enable Droop] = “Enabled”
[Droop Percent] = 5%
[Droop Filter] = 100 ms
[Droop Limit] = 1000
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, see Using Contactors on page
31 .
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.