ABB traction motors for metro

Group drive means that one converter feeds several motors, depending on whether car control or bogie control is used. This configuration keeps down the total cost of the vehicle and is the most common for metros around the world.

With group drive, the traction motors should be designed so that the rotor resistance allows the train to be operated with a specified wheel diameter difference. A high rotor resistance allows for a larger diameter difference, while a low rotor resistance provides higher efficiency.

ABB’s favors die-cast aluminum rotors, allowing for larger wheel diameter differences – prolonging maintenance intervals and reducing costs. Aluminum rotors are also very robust. ABB’s jointless aluminum rotors have proven reliable in thousands of metro motors worldwide.

Fueled by stricter energy efficiency demands, new traction drive solutions are beginning to be explored. One such example is single-axle control for metros, using induction, asynchronous or synchronous motor technologies.

With single-axle control, each converter feeds only one motor. Every axle is controlled individually, allowing for precise adhesive control. The solution also provides very high redundancy.

Using low-resistance copper rotors in the traction motors allows for more demanding mission cycles, while maintaining the vehicle’s high energy efficiency. By utilizing advanced calculation tools, ABB is able to boost the energy efficiency of asynchronous technologies – while being at the R&D forefront for synchronous motors.