Toshiba VF-A7 instruction manual Setting motor constants, ①Slip frequency gain 

Step 2: Setting motor constants

This section describes how to set motor constants. Select the items to be improved and change the related motor constants.

①Slip frequency gain 

This parameter is to adjust the slippage of the motor.

Setting this parameter at a larger number can reduce the slippage of the motor. However, setting it at an excessively large number may result in hunting, etc., and thus cause an unstable operation.

③Motor constant #1  (Primary resistance) (Motor test reports may be useful.) This parameter is to adjust the primary resistance of the motor.

Setting this parameter at a larger value can prevent the drop of the motor torque in low speed ranges due to a voltage drop. However, setting it at an excessively large number may result in large current in low speed range and appearance of overload trip, etc..

③Motor constant #2  (Secondary resistance)

This parameter is to adjust the secondary resistance of the motor.

The larger the set value, the more the slippage of the motor can be compensated.

④Motor constant #3  (Exciting inductance) (A motor test record can be used for this setting.)

This parameter is to adjust the exciting inductance of the motor.

The larger the set value, the more the no-load current can be decreased.

⑤Motor constant #4  (Load inertia moment)

This parameter is to adjust the transient response of the motor.

Setting this parameter at a larger value can reduce overshooting on completion of acceleration or deceleration. Set this parameter at a value, which matches to the effective moment of inertial.

⑥Motor constant #5  (Leak inductance) (Motor test reports may be useful.) This parameter is to adjust the leakage inductance of the motor.

The larger the set value, the larger torque the motor can be produced in high-speed ranges.

F-38