Performance of large line-start permanent magnet synchronous motors

A successful design of a 25 hp permanent-magnet synchronous motor using SmCo/sub 5/ and NdBFe magnets is presented. Expressions to predict the motor run-up and terminal performance are given. The rotor was tested for the straight interior rotor magnet arrangement. A record efficiency of over 94% was obtained at full load with a high power factor when the NdBFe magnets were used. The starting and synchronization were quick and smooth. There was no evidence of temperature limitations on the embedded rotor NdFBe magnets. A reasonable agreement between the computed and measured results was obtained.<
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