Motor overcomes reliability challenges

Commenting on the project, Steve Scurrell, works manager for Synseal, said: “The existing extruder motors were 20 years old and largely obsolete. Although we kept refurbishing them, they were lasting for shorter and shorter times between refurbishments. We knew that if we did not replace them, either could fail at any time and we would lose the use of an extruder line completely. Although we may not lose a huge number of hours, even a minor loss of production time could have a negative effect on our business productivity and this is something we would want to avoid wherever possible.”

At the same time, ABB was looking for a suitable constant torque application to test its new SynRM motor. Phil Nightingale, of ABB authorised value provider Inverter Drive Systems (IDS), explains further: “This was a standard constant torque extruder application, which was ideal to test the capabilities of the SynRM. The servo-motors were long and thin. Although they could have been replaced by normal squirrel cage motors, the SynRM motors were a better fit for the existing installation as they offer more power for their size than conventional motors.”

Said to offer up to 40% more power density than conventional induction motors, a SynRM can be up to two frame sizes smaller than a conventional induction motor, a benefit for machine builders working to space restrictions or for refurbishing existing machines. It offers the high power density of an equivalent permanent magnet motor with the robustness of an asynchronous squirrel-cage motor, says the company.

Because the rotor runs cooler than other technologies, the bearings also run much cooler, making the motor much more reliable.

The two 25 kW motor, together with matched ABB ACS880 drive, was installed on the extruder. IDS installed the drive, while Synseal installed the SynRM motor. This installation included a force vent kit, foot mount and HTL encoder.

As well as curing the reliability and obsolescence problems, the motor also cut 20% off the running costs of the extruder, saving £754 a year on electricity. 

“The motor and drive are now fitted as a permanent installation and we have another machine to convert to this configuration later in the year. The main benefit to us is that we now have much better availability of spare motors off the shelf and know that we can keep our extruders running,” concludes Scurrell..