Insulation-Processing of Copper Die-Cast Squirrel-Cage Rotor on Motor Efficiency in high-speed operation over 10,000 r/min

This paper verifies the effect of a new heat-resistant insulation-processing between rotor core and copper die-cast bar on motor efficiency in high-speed operations. Two prototypes of copper die-cast squirrel-cage rotors are assembled: an insulated-slot rotor and a non-insulated-slot rotor. These rotors are installed to the same stator whose ratings are 0.75 kW, 200 V, 2 poles and 12,000 r/min. Full-load driving tests over 10,000 r/min are implemented. The results suggest that to insulate between the copper die-cast rotor bar and rotor core by the proposed heat-resistant agent contributes to improving the motor efficiency in high-speed and heavy-load operations. In addition the impact of the slot insulation on loss segregation of the copper die-cast induction motor is clarified.