There are several torque limits in the drive. The first to consider is the Maximum Torque Limit. This is the absolute maximum forward torque. The maximum negative torque limit may have its own parameter or it may be the negative of the Maximum Torque Limit.
Typically the Maximum Torque Limit is set at 300%. The percentage is a percentage of the torque calculated from the motor nameplate.
If no other torque limits are enabled, the drive will be limited to the Maximum Torque Limit. Hitting the maximum torque limit in ordinary operation should be a very special and rare occurrence – think Emergency Stop. If this maximum torque limit is reached, drive protection will fault the drive in a few seconds (10 to 60) to protect the motor – not the web handling equipment or the web.
Other torque limit options in the drive may be used to:
- Control the stopping time
- Protect equipment such as extruder screws
- Control tension by torque
During commissioning, it is useful to check the torque limit (by E-Stop) to ensure that the drive and motor are capable of achieving this torque without fault. We learn the most about our equipment when we push it to the limit. The torque limit is an electronic function and if the drive has not been set up or tuned correctly, may not operate as expected.