There are already concepts that would see electric vehicles draw power from cables in the road, thus freeing those vehicles up from lugging around heavy batteries. British firm Texchange, however, is going a step farther – it's developing a system where the motor is in the "road," too.
The company ultimately hopes to see the technology used for mass rapid transit in developing nations, although its more immediate application could be in mine carts. It's based around synchronous linear electric motors.
In a regular cylindrical electric motor, a magnet-equipped rotor spins within a magnetic field-generating stator (that's the part with the copper coils in it). A linear electric motor is sort of like a regular one, except it's "unrolled" to form a slab. The stator is now flat, and the rotor likewise now takes the form of a flat reaction plate. Instead of spinning, the reaction plate shoots across the stator, from one end to the other.
By synchronizing a series of those motors laid end-to-end along a track, a reaction plate could be made to "surf" a traveling magnetic wave all the way down that track in the same way as some maglev trains – but without the levitation. Attach that plate to the underside of a mine cart, and you get a motorless moving cart. Additionally, multiple carts could be made to move independently on one track at the same time, going in either direction and at different speeds.
According to Texchange, not only should the system be more energy-efficient than using heavier motor-equipped carts, but it should also be more reliable, more robust, and allow for the climbing of gradients of over 20 percent. It could conceivably even be used in cable-less elevators.
Texchange managing director Rupert Cruise tells us that the company is currently building a demonstration model with a manufacturing partner in Leicester.