Improved Operating Efficiency
6-35
 Compensating for Insufficient Torque at Startup and Low-speed Opera-
tion (Torque Compensation)
The torque compensation function detects that the motor load has increased, and increases the output torque.
V/f control calculates and adjusts the motor primary loss voltage according to the output voltage (V), and
compensates for insufficient torque at startup and during low-speed operation. Calculate the compensation
voltage as follows: Motor primary voltage loss × parameter C4-01.
Vector control separates the motor excitation current and the torque current by calculating the motor primary
current, and controlling each of the two separately. 
Calculate the torque current as follows: Calculated torque reference × C4-01
Related Parameters
* The display shows the factory settings for Open loop vector 1 (OLV1).  Default settings will change in accordance with the control mode.
Parameter
Number
Name
Description
Setting 
Range
Factory 
Setting
Change 
during 
Operation
Control Methods
Display
V/f 
V/f with 
PG
Open
Loop
Vector
1
Flux
Vector
Open
Loop
Vector
2
C4-01
Torq Comp 
Gain
This parameter sets the gain for 
the Drive's automatic torque boost 
function to match the Drive's 
output voltage to the motor load. 
This parameter helps to produce 
better starting torque. It 
determines the amount of torque 
or voltage boost based upon 
motor current, motor resistance, 
and output frequency.
Note: Adjustment is not normally 
required.
0.00 
to
2.50
1.00 Yes A A A No No
Torq Comp 
Gain
C4-02
Torque 
Compensation 
Primary Delay 
Time
This parameter adjusts the filter 
on the output of the torque 
compensation function. Increase 
to add stability, decrease to 
improve response.
Note: Adjustment is not normally 
required.
0 
to 
10000
20ms
*
No A A A No No
Torq Comp 
Time
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