Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual - Manual (Page 56)

56 Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011
Chapter 1 Detailed Drive Operation
To use the lead function:
1. Set Wld equal to the desired lead in radians/second
2. Set Wlg equal to 5x Wld
3. Wn=Wlg
4. Kn=Wlg/Wld
The torque reference has a notch filter used to eliminate resonance signals. The
notch frequency is set by parameter 118 [Notch Filt Freq]. This frequency is set
to the mechanical resonance in hertz.
Firmware Functions Parameter 147 [FW Functions En] allows the user to enable and display firmware
functions in the drive. When a function is disabled, the parameters cannot be
changed. The parameters associated with the disabled function will not be
displayed on the HIM module. Parameter 149 [FW FunctionsActl] will display
the actual functions that are enabled or disabled. Changes to [FW Functions En]
will take affect immediately.
To view parameters in DriveExecutive for a firmware function that has just been
turned on you can either create a new database after you have enabled the
function in the drive, or turn on the Show hidden parameters feature in
DriveExecutive by selecting View > Options > Components.
Flying Start
The flying start feature is used in sensorless mode to start into a rotating motor, as
quickly as possible, and resume normal operation with a minimal impact on load
or speed.
When a drive running in sensorless mode is started in its normal mode, it initially
applies a frequency of 0 Hz and ramps to the commanded speed. If the drive is
started in this mode with the motor already spinning, large currents will be
generated. An overcurrent trip may result if the current limiter cannot react
quickly enough. The likelihood of an overcurrent trip is further increased if there
is residual voltage on the spinning motor when the drive starts. Even if the current
limiter is fast enough to prevent an overcurrent trip, it may take an unacceptable
amount of time for synchronization to occur and for the motor to reach its
desired frequency. In addition, larger mechanical stress is placed on the
application, increasing downtime and repair costs while decreasing productivity.
ATTENTION: The Flying Start function is only used for sensorless
operation. In all other cases the motor speed is known from the feedback
device and a normal start may be used even if the motor is rotating,
provided the user has determined that the system is safe for re-starting
while rotating.