WEG CFW-10 - Page 68

68
CHAPTER 6 - DETAILED PARAMETER DESCRIPTION
Range
[Factory Setting]
Parameter Description / Notes
P138 0.0 to 10.0
Slip [ 0.0 ]
Compensation 0.1 %
The parameter P138 is used in the motor slip compen-
sation function.
This function compensates the drop of themotor speed
due to load, which is a inherent characteristic relating
to the operation principle of the induction motor.
This speed drop is compensated by increasing the
output frequency (applied to the motor) as a function
of the increase of the active motor current, as shown
in the block diagram and in the V/F curve below.
Slip
Compensation
Active Output
Current (I
a
)
Frequency
Reference (F*)
Ramp Input
Frequency (Fe)
F
Filter P138
Figure 6.9 - Block diagram of the slip compensation function
Figure 6.10 - V/F curve with slip compensation
Output Voltage
(function of
the motor
load)
Output
Frequency
To set the parameter P138 adopt the following
procedure:
- run the motor without load up to approximately
half of the application top speed;
- measure the actual motor or equipment speed;
- apply rated load to equipment;
- increase parameter P138 until the speed reaches
its no-load speed.