Toshiba VF-nC1 - Manual (Page 60)

E6581090
E-8
5
1) Constant torque characteristic
Setting of V/F control mode selection RV to  (V/F constant)
This setting is applied to loads, such as conveyers and cranes that require the same torque as the
rated torque even at low speeds.
Ou
tp
u t v
ol
ta
g
e [%]
Rated voltage of
motor
H
Output frequency (Hz)
XD
Base frequency XN
0
◎ To further increase the torque, increase the setting of the torque boost parameter (XD).
■ Parameter setting
Title Function Adjustment range Default setting
XD Torque boost 1 (%) 0.0～30.0(%) Depends on the model.
The default torque characteristic is set based on the torque characteristic of World Energy series 4P
motors manufactured by Toshiba Industrial Machinery.
When using the inverter with a VF motor or a motor with 6 or more poles, set the torque boost
parameter at 80% or so of the default setting.
When the inverter is used with a special motor with a particular V/F ratio, it requires adjustments.
Excessively boosting torque could results in an overcurrent trip. To avoid this, do not increase torque
by more than 1.2 times the default torque.
2) Correcting the error in rotational speed due to the slippage of the motor
Setting of V/F control mode selection RV to  (Vector control)
Setting this parameter to 3 causes the inverter to monitor the load currents and automatically
correct the error in speed caused by the slippage of the motor. Slip correction gain is adjusted to
correct the error in speed caused by the slippage of the motor.
⇒ See 6.12 for details.
Torque
Rated torque
Rotational speed converted
to frequency
Synchronous
rotational speed Rotational
speed