6-46
6
Machine Protection
Limiting Motor Torque (Torque Limit Function)
This function allows limitation of motor shaft torque independently for each of the four quadrants. The torque
limit can be set as fixed value using parameters or as variable value using an analog input. The torque limit
function can be used with Open Loop Vector and Closed Loop Vector control only.
Related Parameters
Multi-function Digital Output (H2-01 to H2-03)
Setting the Torque Limit Using Parameters
Using L7-01 to L7-04, four torque limits in the following directions can be set individually: Forward drive,
reverse drive, forward regenerative and reverse regenerative (see Fig 6.48)
Fig 6.48 Torque Limit Parameters
Using a Digital Output to Signalize Operation at the Torque Limit
If a multi-function digital output is set for this function (H2-01 to H2-03 is set to “30”), the output is switched
ON when the motor output torque reaches one of the torque limits.
Parameter
No.
Name
Factory
Setting
Change
during
Opera-
tion
Control Methods
V/f
V/f with
PG
Open
Loop
Vector
Closed
Loop
Vector
L7-01 Forward drive torque limit
200%
* 1
* 1. A setting value of 100% equals the motor rated torque.
No No No A A
L7-02 Reverse drive torque limit 200% *1 No No No A A
L7-03 Forward regenerative torque limit 200% *1 No No No A A
L7-04 Reverse regenerative torque limit 200% *1 No No No A A
L7-06 Torque limit time constant 200 ms No No No A No
L7-07 Torque limit operation during accel./decel. 0 No No No A No
Set
Value
Function
Control Methods
V/f
V/f
with
PG
Open
Loop
Vector
Closed
Loop
Vector
30 During torque limit No No Yes Yes
L7-01
Output Torque
Output Speed
L7-03
L7-02
L7-04
Forward
Drive
Reverse
Drive
Reverse
Regenerative
Forward
Regenerative