Torque Compensation Function Adjustments - Omron VARISPEED L7 Manual

Adjusting Slip Compensation Limit (C3-03)
Using parameter C3-03 the upper limit for the slip compensation can be set as a percentage, taking the motor
rated slip as 100%.
If the speed is lower than the target value but does not change even after adjusting the slip compensation gain,
the slip compensation limit may have been reached. Increase the limit, and check the speed again. Always
make sure that the value of the slip compensation limit and reference frequency does not exceed the tolerance
of the machine.
The following diagram shows the slip compensation limit for the constant torque range and fixed output range.
Enable the Slip Compensation Function During Regeneration (C3-04)
Enables or disables the slip compensation function during regenerative operation. The factory setting is
enabled.
Operation Selection when the Output Voltage is Saturated (C3-05)
6
Generally the Inverter cannot output a voltage that is higher than the input voltage. If in the high-speed range
the output voltage reference for the motor (monitor parameter U1-06) exceeds the input voltage, the output
voltage becomes saturated, and inverter cannot respond to speed or load changes. This function automatically
reduces the output voltage to avoid voltage saturation.
Thereby the speed control accuracy can be maintained even at high speeds (around the rated speed of the
motor). By the lowered voltage the current can be around 10% higher compared to the operation without volt-
age limiter.

Torque Compensation Function Adjustments

The torque compensation function detects a rising motor load, and increases the output torque.
In V/f control the inverter calculates the motor primary loss voltage using the terminal resistance value (E2-
05) and adjusts the output voltage (V) to compensate insufficient torque at startup and during low-speed oper-
ation.
The compensation voltage is calculated by the calculated Motor primary voltage loss × parameter C4-01.
In Open Loop Vector control the motor excitation current and the torque producing current are calculated and
controlled separately. The torque compensation affects the torque producing current only.
The torque producing current is calculated by the calculated torque reference × C4-01.
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6-
Slip compensation limit
E1-06: Base frequency
E1-04: Maximum output frequency
Fig 6.9 Slip Compensation Limit
Output frequency