Toshiba VF-AS1 instruction manual Exciting strengthening coefficient Stall prevention factor

E6581301

6.23Increasing the motor output torque further in low speed range

￿￿￿￿￿: Exciting strengthening coefficient

￿￿￿￿￿: Stall prevention factor

The output torque of the motor can adjusted using the parameters described in 6.22 in most cases, but if a finer adjustment is required, use these parameters.

[Parameter setting]

Title	Function	Adjustment range	Default setting
￿￿￿￿￿	Exciting strengthening coefficient	￿￿￿~￿￿￿ %	￿￿￿￿
￿￿￿￿￿	Stall prevention factor	￿￿~￿￿￿	￿￿￿￿

$If the torque needs to be increased in low speed range (10Hz or less as a guide)

Perform auto-tuning according to the instructions in 6.22, and if the torque needs to be increased further in low speed range, first increase the slip frequency gain (￿￿￿￿) to a degree (80% or so as a guide) that hunting of the motor does not occur. Then, increase motor constant 1 (￿￿￿￿) by 1.1 times the current value as a guide. If the torque needs to be increased even further, increase the exciting current factor (￿￿￿￿) to a maximum of 130%.

￿￿￿￿is a parameter that increases the magnetic flux of the motor at low speeds, so specifying a higher value for

￿￿￿￿increases the no-load current. If the no-load current exceeds the rated current, do not adjust this parameter.

$If the motor stalls when operated at frequencies above the base frequency Adjust ￿￿￿￿ (stall prevention factor).

If a heavy load is applied momentarily (transiently), the motor may stall before the load current reaches the stall

6 prevention level (￿￿￿￿). In such a case, a motor stall may be avoided by reducing the value of ￿￿￿￿

gradually.

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