Mitsubishi Electric FR-A800 Series Instruction Manual page 280

The following diagram indicates operation relative to commands given by analog input via terminal 1.
(Forward
command)
• At the STF signal ON, the speed limit value is raised in accordance with the setting of Pr.7.
• Speed control is performed when the actual speed exceeds the speed limit value.
• At the STF signal OFF, the speed limit value is lowered in accordance with the setting of Pr.8.
• Under torque control, the actual operation speed is a constant speed when the torque command and load torque are
balanced.
• The direction of motor torque generation is determined by a combination of the input torque command polarity and the start
signal, as given in the following table.
Polarity of torque
command
+ torque command
- torque command
NOTE
• Once the speed limit is activated, speed control is performed and internal torque limit (Pr.22 Torque limit level) is enabled.
(Initial value) In this case, it may not be possible to return to torque control.
Torque limit should be external torque limit (terminals 1 and 4). (Refer to
• Under torque control, the undervoltage avoidance function (Pr.261 = "11" or "12"), which is one of the power failure time
deceleration-to-stop function, is invalid.
When Pr.261 = "11 (12)", the operation is performed in the same manner as if Pr.261 = "1 (2)".
• Under torque control, perform linear acceleration/deceleration (Pr.29 = "0 (initial value)"). When acceleration/deceleration
patterns other than the linear acceleration/deceleration are selected, the protective function of the inverter may be activated.
(Refer to
• Performing pre-excitation (by using the LX or X13 signal) during torque control (under Real sensorless vector control) may
rotate a motor at a low speed even though a start command (STF or STR) is not given. The inverter at a start command ON
may also rotate the motor at a low speed even though a speed limit value is set to 0. It must be confirmed that the motor running
does not cause any safety problem before performing pre-excitation.
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Speed
Pr.7
∗
Speed Speed Speed
STF
rotation
Speed limit
Torque control operation
operation
(Speed control)
OL
ON
Torque generation direction
STF signal ON
Forward direction (forward
power driving / reverse
regenerative driving)
Reverse direction (forward
regenerative driving / reverse
power driving)
page 372.)
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Speed limit value
∗
Speed limit
operation
(Speed control)
ON
∗When the speed limit activates, torque according to the commanded is not developed.
STR signal ON
Reverse direction (forward
regenerative driving / reverse
power driving)
Forward direction (forward
power driving / reverse
regenerative driving)
page
5.4 Torque control under Real sensorless vector control and Vector control
Pr.8
∗
Time
Torque Speed limit
control operation
operation (Speed control)
ON
245.)
5. PARAMETERS
1
2
3
4
5
6
7
8
9
10
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