Mitsubishi Electric FR-A720-0.4K Instruction Manual page 511

1.6 Low-speed range torque characteristics (Pr.788)
Torque characteristics in a low-speed range can be changed.
Parameter
Number
788
Low-speed range torque
characteristics
P M P M P M
* Current synchronization operation is always performed for IPM motors other than MM-CF, even if "9999" is set.
(1) When the low-speed range torque characteristic is enabled ("9999" (initial value))
· The high frequency superposition control provides enough torque in the low-speed range operation.
· Refer to page 17 for the torque characteristics.
(2) When the low-speed range torque characteristic is disabled ("0")
· The current synchronization operation reduces much motor noise compared with the high frequency superposition
control.
· The torque in a low-speed range is low. Use this setting for an operation with light start-up load.
· Refer to page 17 for the torque characteristics.
REMARKS
 Position control under PM sensorless vector control is not available when the current synchronization operation is selected.
1.7 Setting the acceleration/deceleration time in the low-speed range
(Pr.791, Pr.792)
Parameter
Name
Number
791
Acceleration time in
low-speed range
P M P M P M
792
Deceleration time in
low-speed range
P M P M P M
* Depends on the Pr. 21 Acceleration/deceleration time increments setting. The initial value for the setting range is "0 to 3600s" and the setting
increments is "0.1s".
Initial
Name
Setting
9999
P M P M P M
Initial
Value
9999
9999
Setting
Range
Disables the low-speed range torque characteristic
0
(current synchronization operation).
Enables the low-speed range torque characteristic
9999
*
(high frequency superposition control)
Setting Range
Set the acceleration time in a low-speed
0 to 3600/360s range (less than 1/10 of the rated motor
*
frequency).
The acceleration time set in Pr.7 is applied.
9999 (When the second functions are enabled,
the settings are applied.)
Set the deceleration time in a low-speed
0 to 3600/360s range (less than 1/10 of the rated motor
*
frequency).
The deceleration time set in Pr.8 is applied.
(When the second functions are enabled,
9999
the settings are applied.)
14/24
P M P M P M
t M Å I P Å t Å s
Operation
Description
BCN-C22005-634