Published by B&D Engineering,
Five Tips on Extruder Retro-fits
- 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.
- 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.
- 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.
- 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.
- 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.