Delta CP2000 Series, User Manual

Page: 492 / 868

Chapter 12 Description of Parameter Settings

CP2000
12.1-07-12
 When the setting is too long, the control is stable but the control response is delayed. When the
setting is too short, the response is quick but the control may be unstable. Adjust the setting
according to the stability of the control and response times.

Slip Compensation Filter Time (V/F and SVC Control Mode)
Default: 0.100
Settings 0.001–10.000 sec.
 Change the compensation response time with Pr.07-24 and Pr.07-25.
 If you set Pr.07-24 and Pr.07-25 to 10 seconds, the compensation response is the slowest.
However, the system may be unstable if you set the time too short.

Torque Compensation Gain (V/F and SVC Control Mode)
Default: 0
Settings IM: 0–10 (when Pr.05-33=0)
PM: 0–5000 (when Pr.05-33=1 or 2)

Only applicable in IMVF and PMSVC control modes.

With a large motor load, a part of drive output voltage is absorbed by the short winding resistor;
therefore, the air gap magnetic field is insufficient. This causes insufficient voltage at motor
induction and results in excessive output current but insufficient output torque. Auto-torque
compensation can automatically adjust the output voltage according to the load and keep the air
gap magnetic fields stable to get the optimal operation.

In the V/F control, the voltage decreases in direct proportion when decreasing frequency. It
reduces the torque decrease at low speed due to the AC impedance while the DC resistor is
unchanged. The auto-torque compensation function increases the output voltage at low
frequency to get a higher start torque.

When the compensation gain is set too large, it may cause motor over-flux and result in a too
large output current, overheating the motor or triggering the protection function.
 Slip Compensation Gain (V/F and SVC Control Mode)
Default: 0.00
(1.00 in SVC mode)
Settings 0.00–10.00
 The induction motor needs constant slip to produce magnetic torque. It can be ignored at a
higher motor speed, such as rated speed or 2–3% of slip.
 In operation, the slip and the synchronous frequency are in reverse proportion to produce the
same magnetic torque. The slip is larger with the reduction of synchronous frequency. The
motor may stop when the synchronous frequency decreases to a specific value. Therefore, the
slip seriously affects the motor speed accuracy at low speed.
 In another situation, when you use an induction motor with the drive, the slip increases when the
load increases. It also affects the motor speed accuracy.
 Use this parameter to set the compensation frequency, and reduce the slip to maintain the
synchronous speed when the motor runs at the rated current in order to improve the accuracy of
the drive. When the drive output current is higher than Pr.05-05 (No-load Current of Induction