Five Tips on Extruder Retro-fits

Published by B&D Engineering,

Five Tips on Extruder Retro-fits
  1. The DC motor – If the DC motor is in good shape – save a bundle and stay with DC, ABB is one of the few companies developing modern DC drives with advanced technology. Most companies either do not have DC, so the sales-guy/rep will always push you to AC. The few others that do carry DC often re-package a lesser brand and have difficulty with the complexity of it either during commissioning or after. See our ready-made DC drive kits.
  2. The DC motor is in lousy shape, stick with the AC square frame-motors to match as much as possible with the original foot-print - see additional info via video.
  3. The DC motor generally has a better starting torque curve than the AC designs. However, the system may not be drawing significant current on start-up (unloaded barrel, sound process for start-up, etc.) Do not always assume you must de-rate the drive or increase the HP of the motor from the original design. Do the math and the research.
  4. Pressure control, in many cases, the speed reference of the extruder is controlled from a pressure controller as a stand-alone unit or a PLC. Be prepared to re-tune these as the drive is new and has different dynamics even if staying DC.
  5. OEM designs – sometimes OEMs skimp on torque requirements and service factor, shocking I know. The point here is if the original design is new, inherited from a sister plant, or purchased via auction, work with a group that can assess the machine and discuss the intended loading of the extruder before the retro-fit.
CTolbert VPE