Rockwell Automation 1336VT AC DRIVE 5-300AMP (2-160KW) PROGRAMMING MANUAL - Manual (Page 45)

Local and Serial Port Parameters
Firmware Version 1.01-3.01
Chapter 3
3-31
Parameter 42 Ċ Slip Compensation
Freq P R
P R Enter Hertz
.0
5.0
.0
Read and Write
Units
Minimum Value
Maximum Value
Factory Setting
Important: Parameter 78, Traverse Period, must be set to 0 to allow Slip
Compensation. If not, the drive will fault and display F37 –– P-Jump
Error.
Parameter 42 adds frequency to the drive output. This added frequency will
be seen at the drive Output Frequency Display and will be shown even
when the drive is set to zero speed. At Maximum Frequency however, Slip
Comp will be clamped by the Maximum Frequency set by Parameter 19.
Slip Compensation is based on a percentage of drive output current and
compensates for motor slip in an induction motor. Adding frequency to the
drive output shifts the motor speed towards the synchronous speed of the
motor. By setting Parameter 42, variations in motor speed due to changes
in motor load can be reduced.
The amount of motor load and motor slip is sensed in the drive by
monitoring drive output current. Slip compensation may be set from 0 to 5
Hertz. As the output current of the drive increases from zero to full load,
the drive adds a portion of the slip compensation setting to the output
frequency. If Parameter 66 (Output Frequency) is viewed, it will show the
adjusted frequency — Parameter 65 (Command Frequency), plus a portion
of Parameter 42 (Slip Compensation Frequency).
For example:
•
At 25% of drive full load output current, one-quarter of the hertz set in
Parameter 42 will be added to the output frequency of the drive.
•
At 50% of drive full load output current, one-half of the hertz set in
Parameter 42 will be added to the output frequency of the drive.
•
At 75% of drive full load output current, three-quarters of the hertz set in
Parameter 42 will be added to the output frequency of the drive.
•
At 100% of drive output current, all of the hertz set in Parameter 42 will
be added to the output frequency of the drive.