Parker torque motors replace gearboxes to cut costs and boost efficiency

Many extrusion systems and similar high power machines use AC or DC motors linked to gearboxes to provide the required torque and speed to drive screws, shafts and associated components. This configuration can, however, be noisy, unreliable, draw relatively high levels of power, and, perhaps as importantly, be complex to install, operate and maintain.

By comparison, the latest Parker TMW Series torque motors are based on a proven design of permanent magnet, brushless servo motor, which produces high levels of torque at low operating speeds. Used in combination with Parker AC890 variable speed drives, this enables screws to be connected directly to a motor, with speed and torque being controlled by the drive; unlike traditional gearbox systems, this allows operating parameters to be varied infinitely within the performance envelope of the motor. In practice, this is a far more efficient process as there are virtually no power losses in the transmission mechanism, which helps to reduce energy usage and stresses on moving parts within the system; additionally, the TMW motors are virtually noiseless, have a far smaller footprint, can easily be retrofitted in a matter of hours, and require only minimal maintenance.

Unlike competing torque motors, the TMW range of products feature an integrated thrust bearing, that can be sized according to the application, plus an innovative screw extraction mechanism to simplify installation and maintenance. In addition, Parker is able to offer both standard and customised mechanical interfaces for shafts and barrels, with the shaft being hollow to improve cooling. The TMW range can be used with machinery requiring from 1,200 up to 22,000Nm of torque and running at speeds of between 50 and 500rpm.

Parker quotes typical efficiency improvements from a TMW motor and AC890 drive combination, compared with a traditional gearbox based system, as being up to 10%; used on a standard 110kW extruder running 7,200 hours per year this would produce energy savings of around 7,900€ p.a., based on an energy cost of 0.10€/kWh.