What is Electric Motor ?

Early examples of this system were the front-wheel drive conversions of horse-drawn cabs by Louis Antoine Krieger in Paris in

the 1890s. The Krieger electric landaulet had a drive motor in each front wheel with a second set of parallel windings (bifilar

coil) for regenerative braking.[4] In England, "automatic regenerative control" was introduced to tramway operators by John S.

Raworth's Traction Patents 1903–1908, offering them economic and operational benefits[5] [6] [7] as explained in some detail by

his son Alfred Raworth. These included tramway systems at Devonport (1903), Rawtenstall, Birmingham, Crystal Palace-

Croydon (1906), and many others. Slowing the speed of the cars or keeping it in control on descending gradients, the motors

worked as generators and braked the vehicles. The tram cars also had wheel brakes and track slipper brakes which could stop

the tram should the electric braking systems fail. In several cases the tram car motors were shunt wound instead of series

wound, and the systems on the Crystal Palace line utilized series-parallel controllers.[clarification needed][8] Following a serious

accident at Rawtenstall, an embargo was placed on this form of traction in 1911; the regenerative braking system was

reintroduced twenty years later.[7] Regenerative braking has been in extensive use on railways for many decades. The Baku-

Tbilisi-Batumi railway (Transcaucasus Railway or Georgian railway) started utilizing regenerative braking in the early 1930s. This was especially effective on the steep

and dangerous Surami Pass.[9] In Scandinavia the Kiruna to Narvik electrified railway carries iron ore on the steeply-graded route from the mines in Kiruna, in the north

of Sweden, down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on the way down to Narvik, and these trains generate

large amounts of electricity by regenerative braking, with a maximum recuperative braking force of 750 kN. From Riksgränsen on the national border to the Port of

Narvik, the trains[10] use only a fifth of the power they regenerate.[not in citation given] The regenerated energy is sufficient to power the empty trains back up to the

national border.[11][not in citation given] Any excess energy from the railway is pumped into the power grid to supply homes and businesses in the region, and the railway is

a net generator of electricity.[citation needed]

Electric cars used regenerative braking since the earliest experiments, but this was often a complex affair where the driver had to flip switches between various

operational modes in order to use it. The Baker Electric Runabout and the Owen Magnetic were early examples, which used many switches and modes controlled by

an expensive "black box" or "drum switch" as part of their electrical system.[12][13] These, like the Krieger design, could only practically be used on downhill portions of a

trip, and had to be manually engaged

Improvements in electronics allowed this process to be fully automated, starting with 1967's AMC Amitron experimental electric car. Designed by Gulton Industries[14]

the motor controller automatically began battery charging when the brake pedal was applied. Many modern hybrid and electric vehicles use this technique to extend the

range of the battery pack, especially those using an AC drive train (most earlier designs used DC power).