Question

What is the difference between torque control and torque limiting? Can any of your drives do this?

Answer

Torque control can be done with any of our PID capable drives. Torque control would be a closed loop system where the process variable would be torque. You would have both a torque reference and torque feedback signal. The user would establish a torque signal and allow the drive to control to that set point. Many customers have used torque sensors, load cells, and current transducers to establish an analog input to the drive. Ideally a vector drive would work better than a volts/hertz drive. A vector drive would allow tighter speed regulation and better control in the lower speed range.

Torque limiting can be done with our Hitachi SJ300 series drive. Instead of using an external torque sensor, torque limiting uses the drive's internal current sensor. The operator would set the torque limit, and when that level is exceeded, the drive would act like a governor on a generator. The speed would be restricted until the appropriate level is again maintained. Mechanical devices, in addition to drives, are also employed for torque limiting. Items such as clutches, shear pins, gearboxes, and etc.

---

FAQ Subcategory: None

This item was last updated on 2004-02-25
Document ID: 943

---

The information provided in the AutomationDirect knowledge base is provided "as is" without warranty of any kind. AutomationDirect disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall AutomationDirect or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if AutomationDirect or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion of limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.