Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011 123
Detailed Drive Operation Chapter 1
Sensorless Operation in Frames 9 and Up Drives
In some installations with frames 9 and up drives it may be necessary to increase
parameter 501 [Torque En Dly] if faults occur when the drive is started.
Parameter 501 [Torque En Dly] is used to delay the torque command to the
motor until a preset time to flux up the motor has completed.
Note: The actual delay is twice the value of parameter 501 in firmware prior to
v3.001. A value of 100 ms will actually wait 200 ms in a frame 9 and up PowerFlex
700S drives.
Sensorless Flying Start
Refer to Flying Start on page 56.
Skip Speeds
Note: Skip speeds are only active when parameter 485 [Motor Ctrl Mode] = 3
“V/Hz”.
Some machinery may have a resonant operating speed that must be avoided to
minimize the risk of equipment damage. To assure that the motor cannot
continuously operate at one or more of these points, skip speeds are used.
Configuration:
Parameters 136 [Skip Speed 1]…138 [Skip Speed 3] are available to set the speeds
to be avoided.
The value programmed into the skip speed parameters sets the center point for an
entire “skip band” of speeds. The width of the band (range of speed around the
center point) is determined by parameter 139 [Skip Speed Band]. The range is
split, half above and half below the skip speed parameter value.
Speed
(A)
(A)
(B)
(B)
Skip Speed
Speed
Reference
Drive Output
Speed
Skip + 1/2 Band
Skip – 1/2 Band
1050 RPM
900 RPM
750 RPM
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