Toshiba Tosvert VF-AS1 - Manual (Page 80)

E6581301
E-14
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6) Operating a permanent magnet motor
Setting of V/f control mode selection RV= (PM control)
Permanent magnet motors (PM motors) that are light, small in size and highly efficient, as compared to induction
motors, can be operated in sensorless operation mode. Note that this feature can be used only for specific motors.
For more information, contact your supplier.
7) Performing speed control/torque control with high accuracy using the
motor speed sensor
Setting for V/f control mode selection RV=, (PG feedback vector control 1, 2)
The torque produced by the motor is controlled by means of specified torque command signals. The rotational speed
of the motor depends on the relation between the load torque and the torque produced by the motor.
Set RV to (PG feedback vector control 2) to perform speed/torque control with high accuracy.
Set RV to (PG feedback vector control 1) to operate a motor(s) with a two or more notches lower rating. Note that
the accuracy obtained by RV= is lower than that obtained by setting RV to . Also, RV should be set to to
perform torque control. RV cannot be set to in such a case.
Output torque decreases considerably in regenerative low speed operation (motor slip frequency or less). Set RV to
if regenerative low speed torque is necessary.
+ Motor constant must be set.
If the motor you are using is a 4P Toshiba standard motor and if it has the same capacity as the inverter, there is
basically no need to set the motor constant.
The motor constant can be set in any of the following two ways:
1) The motor constant can be set automatically (auto-tuning 1). Set the extended parameter H=.
⇒ For details, refer to selection 2 in Section 6.22.
2) Each motor constant can be set individually.
⇒ For details, refer to selection 3 in Section 6.22.
8) Precautions on vector control
1) The sensorless vector control exerts its characteristics effectively in frequency areas below the base frequency
(XN). The same characteristics will not be obtained in areas above the base frequency.
2) Set the base frequency between 40 and 120Hz when selecting a sensorless vector control mode (RV=~),
or between 25 and 120Hz when selecting a sensor vector control mode (RV=, ).
3) When setting RV to or , use the inverter along with a general-purpose motor with an equal or one notch lower
rating.
4) Use a motor that has 2 to 16P.
5) Always operate the motor in single operation (one inverter to one motor). (Except for; RV=) Sensorless vector
control cannot be used when one inverter is operated with more than one motor.
6) To operate a motor other than 4P standard motors recommended by Toshiba, enter the information* indicated on
the motor nameplate (*XN (Base frequency), XNX (Base frequency voltage), H (Motor rated capacity),
H
(Motor rated current), H (Motor rated rotational speed), and then set the auto-tuning 1 parameter
H to . If the cable length is in excess of 30m, be sure to perform the auto-tuning 1 mentioned above, even
when using a standard motor recommended by Toshiba. In this case, the torque produced by the motor decreases
more or less around the rated frequency because of a voltage drop cause motor-generated torque in the vicinity of
rated frequency to be somewhat lower.
7) Connecting a reactor or surge voltage suppression filter between the inverter and the motor may reduce motor-
generated torque. Setting auto-tuning 1 may also cause a trip (GVP) rendering sensorless vector control
unusable.
8) Connect speed sensor for vector control with sensor to the motor. Connecting via gear, etc. causes motor's
oscillating or inverter's trip by lack of rigidity.