Rockwell Automation 7000A PowerFlex Medium Voltage AC Drive - Air-Cooled (A Frame) - Manual (Page 226)

4-72 Commissioning
7000A-RM001A-EN-P – January 2011 7000 “A” Frame
4. FluxSpeed Regulator [SYNCHRONOUS MOTORS]
I M P O R T A N T I M P O R T A N T Before the FluxSpeed 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. ACB Port 1.
2.
Set the analog output scale parameter e.g. Anlg Out1 Scale in
Analog Output 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.
ACB Port 1). The setup of the field current reference is complete
and you can proceed with the tuning of the FluxSpeed regulator.
Tuning Procedure (cont.)