Hong Kong trams, commonly known as “Ding Dings”, has been running over centuries since 1904, but is still popular with HK residents and tourists, energetically shuttles in the city with its “core”, which is upgraded by CRRC Yongji Electric Co., Ltd.
On Jan. 28th 2016, the permanent magnet traction system developed for HK trams by CRRC Yongji Electric Co., Ltd. approved by specialists of Beijing Jiaotong University, Southwest Jiaotong University, CRRC and HK Tramways. The result of expert review showed that the design of the system achieved the advanced level of domestic electric transmission system, and was qualified for loading and trial run.
At the earliest, Hong Kong Trams used DC Electric Drive System powered by DC motor. In 2008, special AC Asynchronous Electric Drive System for Hong Kong trams was developed by CRRC Yongji Electric CO., LTD. It is not only improved the reliability of the system, but also become smaller and easier maintenance. In April 2009, the first AC Asynchronous Electric Drive system was delivered. And it’s the first fully update for electric transmit system of ‘Centuries Ding Dings’. At present, 71 nos AC asynchronous electric transmission system were supplied by Yongji and “Ding Dings” operation was guaranteed.
With AC Asynchronous System Trams increasing, the grid capacity of Hong Kong Tramways DC power station cannot meet the operational requirement. So, at the beginning of 2015, Yongji Electric began to develop more energy-efficient AC Permanent Magnet Electric Drive System for Hong Kong Tramways. At present, the system has been completed prototype producing, type testing, combined testing and passed expert review. Also, it is going to carry out the loading and trial run inspection. Regarding Permanent Magnet Traction Technology, a few enterprises like Alstom etc., have the experience in mass application so far. However, the development of Traction Permanent Magnet Synchronous Motor and Permanent Magnet Electric Driving System in domestic is still in its primary stage. It is a weak field that the Permanent Magnet Electric Drive System is applied to urban rail vehicle so far. The Hong Kong Tramways Permanent Magnet Electric Drive System is another new product in the field of rail vehicle for CRRC Yongji Electric Company besides the Electric Vehicles, Marine Propulsion System and so on. Permanent magnet motor is more suitable for urban rail transit vehicles, because of small size, light weight, high efficiency, steady speed, low noise, high reliability and so on. Through a large number of researches and actual running instances in the domestic and overseas, energy-efficient is a prominent advantage in the field of urban rail transit. Under the same operating conditions, Permanent Magnet Traction System could save more than 20% energy compared with Asynchronous Traction System, and the ability of energy saving increased with the performance of regenerative braking increased. At present , on condition of running ten hours and 120 km per day , the power consumption of Hong Kong trams is 50000 KWH per year with the Asynchronous Traction System, however, the trams with Permanent Magnet Traction System will at least reduce 9000 KWH of power consumption per year. (March 18)