The torque limit function limits the internal torque reference for the drive to and keeps the torque from the motor constant. This function limits the torque applied to loads and regenerative torque to a value less than a set quantity. This function also prevents damage to machinery and increases the reliability of continuous operation. You can set torque limits individually for the four quadrants, which include torque direction (motoring/regeneration) and direction of motor rotation (forward/reverse). When the torque reference value is at the set torque limit, the MFDO terminal set for During Torque Limit [H2-xx = 30] activates.

Note:

  • The drive output current limits maximum output torque. The drive limits torque to 150% of the rated output current for Heavy Duty Rating (HD) and to 110% of the rated output current for Normal Duty Rating (ND). The actual output torque is not more than the limits of the drive rated output current when you set the torque limit to a high value.

  • When you use torque limits for lifting applications, do not lower the torque limit value too much. When the torque limit function is triggered, falls and rollbacks can occur because of sudden acceleration stops and stalls of the motor.

Configuring Settings

Use one of these methods to set torque limits:

  • Individually set the four torque limit quadrants using L7-01 to L7-04 [Torque Limit].

  • Use MFAI to individually set the four torque limit quadrants. Set H3-02, H3-10 = 10, 11, 12 [MFAI Function Select = Forward Torque Limit, Reverse Torque Limit, Regenerative Torque Limit].

  • Use MFAI to set all four torque limit quadrants together. Set H3-02, H3-10 = 15 [General Torque Limit].

  • Use a communication option to set all four torque limit quadrants together.

Figure 1 shows the configuration method for each quadrant.

Figure 1. Torque Limits and Analog Input Setting Parameters
Note:

  • When L7-01 to L7-04 and analog inputs or communication option torque limits set torque limits for the same quadrant, the drive enables the lowest value.

    In this example of parameter settings, the torque limit for quadrant 1 is 130% and the torque limit for quadrants 2, 3, and 4 is 150%.

    Settings: L7-01 = 130%, L7-02 to L7-04 = 200%, and MFAI torque limit = 150%

  • The drive output current limits maximum output torque. The torque limit is 150% of the rated output current for HD and to 120% of the rated output current for ND. The actual output torque is not more than the limits of the drive rated output current when you set the torque limit to a high value.