Mitsubishi Electric FR-A800 Series Instruction Manual page 253

• Use Pr.85 Excitation current break point to change the low-speed range, and use Pr.86 Excitation current low-speed
scaling factor to change the torque in the low-speed range. When Pr.85 = "9999 (initial value)", a predetermined
frequency is used. When Pr.86 = "9999 (initial value)", a predetermined scaling factor is used (refer to
Pr.803 setting
The torque changes according to
0 (initial value)
the scaling factor set in Pr.86.
1 Constant torque
2 Constant torque
10 Constant torque
The torque changes according to
11
the scaling factor set in Pr.86.
*1 This is applicable only under Real sensorless vector control. The upper limit of the torque at 0 Hz is determined by multiplying the torque limit in
the constant-torque range by the scaling factor set in Pr.86.
• To avoid overload or overcurrent of the inverter or motor, use Pr.801 Output limit level to limit the torque current.
Pr.801 setting
0 to 400%
9999
Pr.803=0
Torque
Low-speed
Constant torque
range
range
Torque rise limit
Pr.85
Pr.803=2
Torque
Low-speed
range
Pr.801
Constant torque
limit
Pr.85
Pr.803=10
Torque
Low-speed Constant torque
range
range
Constant torque limit
Pr.85
NOTE
• When the torque limit setting value (Pr.22, Pr.812 to Pr.817, etc.) is less than the value set in Pr.801, the Pr.801 setting is
used for limiting the torque current.
 Trip during torque limit operation (Pr.874)
• The inverter can be set to be shut off at activation of torque limit and stalling of the motor.
252
5. PARAMETERS
5.3 Speed control under Real sensorless vector control, vector control, PM sensorless vector control
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Torque characteristic in low-
speed range
*1
*1
Set the torque current limit level.
The torque limit setting value (Pr.22, Pr.812 to Pr.817, etc.) is used for limiting the torque current.
Constant power range
Constant power limit
Rated speed Speed
Constant torque
Constant power range
range
Torque reduction when the
output is limited
Constant torque
limit
Rated speed
Constant power range
Constant power limit
Rated speed Speed
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Torque characteristic in constant-power range
Torque characteristic
Constant motor output
Constant torque
Constant torque
Constant motor output
Constant torque
Description
Pr.803=1
Torque
Low-speed
range
Constant torque limit
Pr.85
When the output limit
is not exceeded
Speed
Pr.803=11
Torque
Low-speed
range
Torque rise limit
Pr.85
page
Output limit
—
Without
With
—
Without
Constant torque
Constant power range
range
Constant torque limit
Rated speed Speed
Constant torque
range Constant power range
Constant torque limit
Rated speed Speed
711).