Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 240)

Commissioning 4-81
7000 “B” Frame 7000-UM150I-EN-P – June 2013
Synchronous Motor Flux Regulator
This section applies only to firmware revision 3.001 and higher.
Before the flux regulator can be tuned, the analog output for the field
current reference must be set up.
Configuring the Field Current Reference
Excitation for the synchronous motor is provided by a current regulated
field supply, either a dc supply for a slip ring or dc brushless machine,
or a three phase ac supply for an ac brushless machine. The drive
provides an analog current reference as an input to the field supply.
The analog current reference has a range of 0-10V, where 0V
corresponds to zero field current and 10V corresponds to maximum
field current. The scaling of the analog current reference must be
adjusted to achieve a linear relationship between the current reference
and the actual field current. If this is not done, the flux regulator may
be unstable. The scaling of the analog output can be adjusted using the
following procedure:
1. Temporarily assign variable “Autotune Lmd” in “Autotuning” to
the analog output used to control the field supply (e.g. CIB Port 1).
2. Set the analog output scale parameter (e.g. Analog CIB Port 1
Scale) in “Analog Parameters” to:
Analog Scale = maximum analog input of field supply / 10V
3. Set “Autotune Lmd” to a value of 10.00. Confirm that the reference
input of the field supply is at its maximum value. Adjust the
analog output scaling parameter if necessary.
4. Start the field supply and confirm that the field current goes to its
maximum value. If necessary, adjust the field supply to achieve a
field current slightly above rated.
CAUTION: Applying maximum field current to a stationary machine
for an extended period may damage the exciter. Adjust the current as
quickly as possible.
5. Stop the field supply. Assign variable “I Field Command” in “Flux
Control” to the analog output used to control the field supply (e.g.
CIB Port 1). The setup of the field current reference is complete
and you can proceed with the tuning of the flux regulator.