Concepts Regarding Torque Control; Applied To Application Where The Direction Of Rotation Does Not Change - Toshiba TOSVERT VF-AS1 Instruction Manual

4. Concepts regarding torque
control
4.1 Applied to application where the direction
of rotation does not change
Polarities of torque command and torque limit
If the direction of rotation does not change continuously because of the machine characteristics, the
torque control is used with f435 (Prohibition of rotation in any direction other than the specified one (F
or R)) =1 (enabled). The direction of rotation of the motor is set by a command: F (forward run signal) or R
(reverse run signal).
Reverse run commands enabled (R)
f443 : Regenerative braking
Reverse run
f441 : Power running torque
In paper manufacturing lines and so on, once machines have been set up, the directions of rotation of their
motors are fixed and not be changed in succession, and when controlling the operation of the entire
system, the torque produced in the desired direction of rotation (direction specified by a rotation
command) is assumed to be positive torque and the torque produced in the direction opposite to that
specified by the rotation command is assumed to be negative torque. For example, as shown in the next
figures (inverter 1 and 2), the directions of rotation of the motors that drive rolls arranged in a line and
rotate to send materials in one direction along the manufacturing line differ according to whether they are
placed on this side or other side of the rolls that they drive. In this example, a selection between F
(forward) and R (reverse) commands is made for each inverter according to the circumstances under
which the system is operated. (Inverter 1: forward run, inverter 2: reverse run) However, torque commands
from the host control unit of the system to the inverters have unified polarity and the direction of rotation of
each individual motor is ignored. For this reason, this setting is usually used for systems that use motors
whose directions of rotation depend on the circumstances under which the system is operated and are not
be changed in succession. To prevent a motor from rotating in the direction opposite to that specified by a
command under normal conditions, this setting is used with parameter f435 (prohibition of rotation in
opposite direction (F or R) set to 1 . It can also be used for fixing the side from which a rewinder sends out
the material: upper or lower side.
torque limit
Region ②
Region ③
limit
Forward run commands enabled (F)
f441 : Power running torque
limit
Region ①
Forward run
Region ④
f443 : Regenerative braking
torque limit
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