Performance Characterization and Energy Savings Assessment of a Radial Flux Surface Permanent Magnet Motor Technology

Research output: NRELTechnical Report


This project is part of the National Renewable Energy Laboratory's (NREL's) "Commercialization Assistance Program" to provide technical expertise to help emerging companies overcome technical barriers to commercialization. In this study, NREL has evaluated the efficiency and energy saving potential of a novel motor technology designed by ZEUS Motor Inc. located in Wheat Ridge, Colorado. The motor expands on permanent magnet AC motor (PMAC) design to create a new "radial flux, surface PMAC", or RF-sPMAC motor that is expected to outperform other novel motor technologies on the market. Here, the motor showed considerable energy benefits over typical induction motors. The motor benefits from a tightly-packed magnetic steel and copper stator that allows the motor size to be reduced to a thin disc with an internal cavity 1/30th the size of a traditional induction motor. The housing is also aluminum which is magnetically benign. This eliminates the need for external cooling (up to 25 HP), in addition to reducing power consumption. The objective of this project is to compare the performance of the motor against a comparable common alternative, and then model energy savings in two scenarios using those results. The project is therefore composed of two phases: 1) Laboratory characterization of the ZEUS RF-sPMAC under various torque and speed scenarios using a VFD to generate a complete performance map, and compare with available data on a comparable induction motors with equivalent electrical and mechanical specifications; 2) Modelling estimate of the daily and annual energy and demand savings against a comparable induction motor when used in 1) a conveyor belt system, and 2) water pump system.
Original languageAmerican English
Number of pages49
StatePublished - 2023

NREL Publication Number

  • NREL/TP-5500-85342


  • conveyor energy
  • dynamometer
  • motor energy savings
  • motor retrofit
  • novel motor technology
  • PM AC motor
  • pump energy
  • radial flux
  • radial flux surface permanent magnet motor
  • RF-sPMAC
  • sPMAC
  • surface permanent magnet
  • surface permanent magnet motor


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