英国Derby铁道科学院在1976年年底制成了该院从1974年起着手研究的一种非传统性的新型牵引电动机——外转子牵引电动机。由于变频器使用现代大功率可控硅元件,从而能实现由直流牵引过渡的交流异步牵引。英国铁路认为牵引用异步感应电机在很多方面要比用直流电动机优越。比如异步电机重量轻、无换向器、有较高的转速以及比同等功率的直流电动机体积小。由于无换向器,所以造价低,而且还可以减少再生制动工况时所出现的一些问题,同时这种电动机的抗震 At the end of 1976, the British Derby Academy of Railway Sciences made a non-traditional new traction motor-external rotor traction motor that the institute started from 1974 onwards. Because the frequency converter uses the modern high-power silicon controlled element, thus can realize the AC asynchronous traction that the DC traction transits. British Rail believes that traction asynchronous induction motors are superior to DC motors in many ways. Induction motors, for example, are light weight, have no commutator, have higher speeds and are smaller than DC motors of comparable power. Because there is no commutator, so the cost is low, but also can reduce the regenerative braking conditions when some of the problems occur, while the motor of the earthquake