Low Speed Asynchronous Motors for Minerals Milling Applications

Traditional motors for milling technology has relied on either Wound Rotor Induction, Low Speed Synchronous Motors, or Asynchronous Induction Motors with mechanical gear reducers. A new alternative is now offered: The Low Speed Asynchronous Motor. This alternative provides the benefit of reduced complexity, higher efficiency and both lower capital and operating costs. The combination of the Low Speed Asynchronous Motor with an Adjustable Frequency Drive affords the benefit of flexibility in grinding at different speeds and controlling the rate and energy used during start up and shut down. In addition, operating protections can be added that cannot exist in motors connected directly to the utility. A comparison of different motor types for milling applications is provided. This comparison will analyze initial cost, cost of ownership, energy use, complexity and reliability. The result is intended to provide a reference for motor choices in milling applications. In addition, the actual application of this technology at a mine site will be presented.