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6.4 Light-load Acceleration Function
6.4.1 Light-load Acceleration 1 Function
If the load is detected as being lighter than the amount of the output current or the torque reference, then the
frequency reference is increased and the drive continues to run. This can help constrict operation time.
This function determines whether or not the acceleration is allowed (Light-load) to the frequency reference that has
been set. In other words, when Light-load is operating, the drive can still run at the set frequency reference.
Accordingly, the command following Light-load needs to be the frequency reference. See "Appendix-1: Parameter
Calculations" for more information when setting this parameter.
When enabling or disabling Light-load 1 via one of the digital inputs, Multi-Function Input (H1-01~05) needs to be
set to "30". To have Light-load always enabled, set the Light-load Control Selection (parameter S4-01) to "1".
Light-load Acceleration 1 Function is Enabled
Multi-Function Input Function Setting
S4-01 Setting
Light-load 1 Acceleration Enabled /Disabled
Open
Output frequency does not exceed S4 -06 (detection frequency).
H1-01 ~ H1-05 set to “30”
Digital
Input Closed
Not related to setting.
1: (Acceleration 1 function
enabled)
Light-load acceleration function is enabled.
2: (Acceleration 2 function
enabled)
For the operation, refer to 6.4.2(Light-load acceleration 2 function).
“ 30”
not
set to H1-01 ~ H1-05
0: (Disabled)
Light-load acceleration function is disabled.
Ti is operated by frequency reference.
Multi-Function Input (Light-load Acceleration 1 Enable/Disable)
Setting
Name
Message
Description
30
Light-load Acceleration 1
Enable/Disable
Light-load Acceleration 1
Selection
Light-load acceleration 1 function enable or disable is
selected.
Operation Description
FAMF
: Forward Light-load 1 Max Frequency (S4-02)
FAD
: Light-load 1detection Frequency (S4-06)
FAMR : Reverse Light-load 1Max Frequency (S4 -03)
TA
: Light-load 1detection Time (S4 -07)
IFAT : Forward Light-load 1 Detection Torque (S4 -04)
based on motor rating
IRAT : Reverse Light-load 1 Detection Torque (S4 -05)
based on motor rating
(1) With S4-01 set to "1" (Light-load Function Selection), or with Light-load enabled via one of the digital inputs, the
drive will accelerate beyond the frequency in FAD if a frequency reference larger than the Light-load 1 Detection
Frequency (FAD) is detected. After 1/3 of the Light-load 1 Detection Time (TA) has passed, a load check is
performed by comparing the torque reference and Light-load 1 Detection Torque (IFAT, or IRAT in reverse).
(2) If the torque command (or output current in V/f Mode) lasts for 2/3 of the time set to TA but remains below the time
in FAT (or IRAT in reverse), then the drive will re-accelerate (Light-load) and run at either the previously set
frequency reference or the Light-load 1 Max Frequency (FAMF, or FAMR in reverse), whichever reference is lower.
(3) If the torque command (or output current in V/f Mode) is greater than IFAT (or IRAT in Reverse), then the drive will
continue running at the frequency set to FAD. Even if the torque reference decre ases, re-acceleration (Light-load)
will still not occur.
Hi-Speeds
Lo-Speeds
closed
open
terminal A1 Input
FAD
Lo-Speed
TA
IFAT (IFRT)
Run Command (FWD/REV)
Terminal S1 -S2
Output Freq
Inverter Torque Command
(or Inverter Output Current)
1
3
× TA
2
3
× TA
Runs at FAMF (FAMR) or the Freq Ref, whichever is lower
output frequency when the load is deemed "heavy" by the
load check
Here, no acceleration if the detection torque level is exceeded
even once
Speed Command Input
Terminal A1
Summary of Contents for CIMR-F7Z
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