This series of motors feature squirrel-cage windings placed on the rotor. They can start automatically at power frequency without the need for a frequency converter, offering high efficiency and significant energy-saving effects. The speed is constant and they can operate at synchronous speed. As rare earth permanent magnet motors do not require reactive excitation current, the power factor can be significantly improved to the limit value (1.0). It can adapt to various load conditions and has a significant energy-saving effect.