Like any other conventional Motor, the External Rotor Motor has a wound Stator and an Aluminum Die Cast Rotor. The only difference is that in this case the Rotor moves externally around the stator. Salient Features : CE Mark and manufactured to EN 60335-1 Compact in size, Continuous Rating with High Efficiency, Variable Speed by changing Input Voltage or Frequency, Dynamically Balanced in 2 planes as per grade 2.5 of ISO 1940-1973 in accordance to VDI 2060, Winding Surge and H.V. Tested. Double Shielded pre lubricated Ball Bearings.