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99-617: Steep gradients on the Natal section of South African Railways, particularly in the Natal Midlands meant that electrification could be beneficial, particularly if regenerative braking was employed. In 1921 the estimated cost of the electrification project, inclusive of the Power Station was £ 2,033,000. Building started in 1921 and the power station was opened in 1926 with a capacity of 60 MW. Initially it only provided power for

198-428: A battery or a capacitor . Once stored, this power can then be later used to aid forward propulsion . Because of the electrified vehicle architecture required for such a braking system, automotive regenerative brakes are most commonly found on hybrid and electric vehicles . This method contrasts with conventional braking systems, where excess kinetic energy is converted to unwanted and wasted heat due to friction in

297-399: A ferromagnetic core. Electric current passing through the wire causes the magnetic field to exert a force ( Lorentz force ) on it, turning the rotor. Windings are coiled wires, wrapped around a laminated, soft, iron, ferromagnetic core so as to form magnetic poles when energized with current. Electric machines come in salient- and nonsalient-pole configurations. In a salient-pole motor

396-532: A flywheel ) or as electrical energy (as in a battery or supercapacitor ). Two minor incidents were reported during testing of KERS systems in 2008 . The first occurred when the Red Bull Racing team tested their KERS battery for the first time in July: it malfunctioned and caused a fire scare that led to the team's factory being evacuated. The second was less than a week later when a BMW Sauber mechanic

495-430: A magnetic field that passes through the rotor armature, exerting force on the rotor windings. The stator core is made up of many thin metal sheets that are insulated from each other, called laminations. These laminations are made of electrical steel , which has a specified magnetic permeability, hysteresis, and saturation. Laminations reduce losses that would result from induced circulating eddy currents that would flow if

594-404: A 100- horsepower induction motor currently has the same mounting dimensions as a 7.5-horsepower motor in 1897. In 2022, electric motor sales were estimated to be 800 million units, increasing by 10% annually. Electric motors consume ≈50% of the world's electricity. Since the 1980s, the market share of DC motors has declined in favor of AC motors. An electric motor has two mechanical parts:

693-431: A 20-hp squirrel cage and a 100-hp wound rotor with a starting rheostat. These were the first three-phase asynchronous motors suitable for practical operation. Since 1889, similar developments of three-phase machinery were started Wenström. At the 1891 Frankfurt International Electrotechnical Exhibition, the first long distance three-phase system was successfully presented. It was rated 15 kV and extended over 175 km from

792-470: A commutator-type direct-current electric motor was built by American inventors Thomas Davenport and Emily Davenport , which he patented in 1837. The motors ran at up to 600 revolutions per minute, and powered machine tools and a printing press. Due to the high cost of primary battery power , the motors were commercially unsuccessful and bankrupted the Davenports. Several inventors followed Sturgeon in

891-463: A comparatively small air gap. The St. Louis motor, long used in classrooms to illustrate motor principles, is inefficient for the same reason, as well as appearing nothing like a modern motor. Electric motors revolutionized industry. Industrial processes were no longer limited by power transmission using line shafts, belts, compressed air or hydraulic pressure. Instead, every machine could be equipped with its own power source, providing easy control at

990-418: A contributing factor in the fatal crash of Jules Bianchi at the 2014 Japanese Grand Prix . Bosch Motorsport Service is developing a KERS for use in motor racing. These electricity storage systems for hybrid and engine functions include a lithium-ion battery with scalable capacity or a flywheel , a four to eight kilogram electric motor (with a maximum power level of 60 kW or 80 hp), as well as

1089-694: A drive motor in each front wheel with a second set of parallel windings ( bifilar coil ) for regenerative braking. The Orwell Electric Truck introduced by Ransomes, Sims & Jefferies in England during WW1 used regenerative braking switched in by the driver. 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 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

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1188-402: A flywheel can be described by this general energy equation, assuming the flywheel is the system: Electric motor An electric motor is a machine that converts electrical energy into mechanical energy . Most electric motors operate through the interaction between the motor's magnetic field and electric current in a wire winding to generate force in the form of torque applied on

1287-430: A form that can be either used immediately or stored until needed. Typically, regenerative brakes work by driving an electric motor in reverse to recapture energy that would otherwise be lost as heat during braking, effectively turning the traction motor into a generator. Feeding power backwards through the system like this allows the energy harvested from deceleration to resupply an energy storage solution such as

1386-422: A generator and the other as motor. The drum rotor was introduced by Friedrich von Hefner-Alteneck of Siemens & Halske to replace Pacinotti's ring armature in 1872, thus improving the machine efficiency. The laminated rotor was introduced by Siemens & Halske the following year, achieving reduced iron losses and increased induced voltages. In 1880, Jonas Wenström provided the rotor with slots for housing

1485-401: A kinetic energy recovery system" in 2007. Peugeot was the first manufacturer to unveil a fully functioning LMP1 car in the form of the 908 HY at the 2008 Autosport 1000 km race at Silverstone. On electric bicycles, regenerative braking can be used in principle. However, as of 2024 it is rarely used on bicycles, mainly because it requires a direct-drive hub motor (while many bicycles use

1584-454: A maximum recuperative braking force of 750  kN . From Riksgränsen on the national border to the Port of Narvik, the trains use only a fifth of the power they regenerate. The regenerated energy is sufficient to power the empty trains back up to the national border. Any excess energy from the railway is pumped into the power grid to supply homes and businesses in the region, and the railway

1683-839: A mid-drive motor which drives the chain), and because it cannot be combined with a freewheel mechanism. Also, the amount of energy regenerated is typically too low to be worthwhile. Regenerative braking is also possible on a non-electric bicycle. The United States Environmental Protection Agency , working with students from the University of Michigan , developed the hydraulic Regenerative Brake Launch Assist (RBLA). Many hybrid electric and fully electric vehicles employ regenerative braking in conjunction with friction braking, Regenerative braking systems are not able to fully emulate conventional brake function for drivers, but there are continuing advancements. The calibrations used to determine when energy will be regenerated and when friction braking

1782-437: A model electric vehicle that same year. A major turning point came in 1864, when Antonio Pacinotti first described the ring armature (although initially conceived in a DC generator, i.e. a dynamo). This featured symmetrically grouped coils closed upon themselves and connected to the bars of a commutator, the brushes of which delivered practically non-fluctuating current. The first commercially successful DC motors followed

1881-425: A rotating bar winding rotor. Steadfast in his promotion of three-phase development, Mikhail Dolivo-Dobrovolsky invented the three-phase induction motor in 1889, of both types cage-rotor and wound rotor with a starting rheostat, and the three-limb transformer in 1890. After an agreement between AEG and Maschinenfabrik Oerlikon , Doliwo-Dobrowolski and Charles Eugene Lancelot Brown developed larger models, namely

1980-410: 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. 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

2079-509: A serious safety hazard: in many early electric vehicles with regenerative braking, the same controller positions were used to apply power and to apply the regenerative brake, with the functions being swapped by a separate manual switch. This led to a number of serious accidents when drivers accidentally accelerated when intending to brake, such as the runaway train accident in Wädenswil, Switzerland in 1948, which killed twenty-one people. In

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2178-398: A solid core were used. Mains powered AC motors typically immobilize the wires within the windings by impregnating them with varnish in a vacuum. This prevents the wires in the winding from vibrating against each other which would abrade the wire insulation and cause premature failures. Resin-packed motors, used in deep well submersible pumps, washing machines, and air conditioners, encapsulate

2277-584: A type of actuator . They are generally designed for continuous rotation, or for linear movement over a significant distance compared to its size. Solenoids also convert electrical power to mechanical motion, but over only a limited distance. Before modern electromagnetic motors, experimental motors that worked by electrostatic force were investigated. The first electric motors were simple electrostatic devices described in experiments by Scottish monk Andrew Gordon and American experimenter Benjamin Franklin in

2376-493: A world record, which Jacobi improved four years later in September 1838. His second motor was powerful enough to drive a boat with 14 people across a wide river. It was also in 1839/40 that other developers managed to build motors with similar and then higher performance. In 1827–1828, Jedlik built a device using similar principles to those used in his electromagnetic self-rotors that was capable of useful work. He built

2475-592: A wound rotor forming a self-starting induction motor , and the third a true synchronous motor with separately excited DC supply to rotor winding. One of the patents Tesla filed in 1887, however, also described a shorted-winding-rotor induction motor. George Westinghouse , who had already acquired rights from Ferraris (US$ 1,000), promptly bought Tesla's patents (US$ 60,000 plus US$ 2.50 per sold hp, paid until 1897), employed Tesla to develop his motors, and assigned C.F. Scott to help Tesla; however, Tesla left for other pursuits in 1889. The constant speed AC induction motor

2574-510: Is rectified for DC motors). In areas where there is a constant need for power unrelated to moving the vehicle, such as electric train heat or air conditioning , this load requirement can be utilized as a sink for the recovered energy via modern AC traction systems . This method has become popular with North American passenger railroads where head end power loads are typically in the area of 500 kW year round. Using HEP loads in this way has prompted recent electric locomotive designs such as

2673-497: Is a net generator of electricity. Electric cars used regenerative braking since the earliest experiments, but this initially required the driver 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. These, like

2772-567: Is available. The 240 mm diameter flywheel weighs 5.0 kg and revolves at up to 64,500 rpm. Maximum torque is 18 Nm (13.3 ftlbs). The system occupies a volume of 13 litres. Formula One have stated that they support responsible solutions to the world's environmental challenges, and the FIA allowed the use of 60 kW (82 PS; 80 hp) KERS in the regulations for the 2009 Formula One season . Teams began testing systems in 2008: energy can either be stored as mechanical energy (as in

2871-400: Is insufficient to safely stop the vehicle – will not wear out as quickly as they would in a vehicle relying solely on traditional brakes. The most common form of regenerative brake involves an electric motor functioning as an electric generator. In electric railways , the electricity generated is fed back into the traction power supply . In battery electric and hybrid electric vehicles,

2970-567: Is not by itself sufficient as the sole means of safely bringing a vehicle to a standstill, or slowing it as required, so it must be used in conjunction with another braking system such as friction -based braking. Regenerative and friction braking must both be used, creating the need to control them to produce the required total braking. The GM EV-1 was the first commercial car to do this. In 1997 and 1998, engineers Abraham Farag and Loren Majersik were issued two patents for this brake-by-wire technology. Early applications commonly suffered from

3069-522: Is reduced by regenerative braking on streetcars ( AE ) or trams ( CE ) in Oranjestad, Aruba . Designed and built by TIG/m Modern Street Railways in Chatsworth , USA, the vehicles use hybrid/electric technology: they do not take their power from external sources such as overhead wires when running but are self-powered by lithium batteries augmented by hydrogen fuel cells . The energy of

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3168-699: Is similar as it also forms part of the driveline assembly. However, the whole mechanism including the flywheel sits entirely in the vehicle's hub (looking like a drum brake). In the CPC-KERS, a differential replaces the CVT and transfers torque between the flywheel , drive wheel and road wheel. The first of these systems to be revealed was the Flybrid. This system weighs 24 kg and has an energy capacity of 400 kJ after allowing for internal losses. A maximum power boost of 60 kW (82 PS; 80 hp) for 6.67 seconds

3267-451: Is the need to closely match the generated current with the supply characteristics and increased maintenance cost of the lines. With DC supplies, this requires that the voltage be closely controlled. The AC power supply and frequency converter pioneer Miro Zorič and his first AC power electronics have also enabled this to be possible with AC supplies. The supply frequency must also be matched (this mainly applies to locomotives where an AC supply

3366-468: Is used on some parts of the London Underground , achieved by having small slopes leading up and down from stations. The train is slowed by the climb, and then leaves down a slope, so kinetic energy is converted to gravitational potential energy in the station. This is normally found on the deep tunnel sections of the network and not generally above ground or on the cut and cover sections of

3465-491: Is used to slow down the vehicle affects the way the driver feels the braking action. The regenerative braking system (RBS) of electric automobiles is the key mechanism for recovering braking energy. With the help of RBS, the efficiency has been significantly improved. RBS affects the fuel economy, emissions, safety, and other functions of electric vehicles. It significantly improves the vehicle's energy recovery rate and helps improve stability and reliability. Power consumption

3564-475: The 2009 Hungarian Grand Prix on 26 July 2009. Their second KERS equipped car finished fifth. At the following race, Lewis Hamilton became the first driver to take pole position with a KERS car, his teammate, Heikki Kovalainen qualifying second. This was also the first instance of an all KERS front row. On 30 August 2009, Kimi Räikkönen won the Belgian Grand Prix with his KERS equipped Ferrari. It

3663-483: The 2009 Le Mans Series season , although it was not capable of scoring championship points. Peugeot plans also a compressed air regenerative braking powertrain called Hybrid Air. McLaren began testing of their KERS in September 2008 at the Jerez test track in preparation for the 2009 F1 season, although at that time it was not yet known if they would be operating an electrical or mechanical system. In November 2008 it

3762-457: The ALP-46 and ACS-64 to eliminate the use of dynamic brake resistor grids and also eliminates any need for any external power infrastructure to accommodate power recovery allowing self-powered vehicles to employ regenerative braking as well. A small number of steep grade railways have used 3-phase power supplies and induction motors . This results in a near constant speed for all trains, as

3861-483: The South Side Elevated Railroad , where it became popularly known as the " L ". Sprague's motor and related inventions led to an explosion of interest and use in electric motors for industry. The development of electric motors of acceptable efficiency was delayed for several decades by failure to recognize the extreme importance of an air gap between the rotor and stator. Efficient designs have

3960-755: The Tokachi 24 Hours race in July 2007. BMW has used regenerative braking on their E90 3 Series as well as in current models like F25 5 Series under the EfficientDynamics moniker. Volkswagen have regenerative braking technologies under the BlueMotion brand in such models as the Volkswagen Golf Mk7 and Mk7 Golf Estate / Wagon models, other VW group brands like SEAT , Skoda and Audi . KTM racing boss Harald Bartol has revealed that

4059-439: The armature . Two or more electrical contacts called brushes made of a soft conductive material like carbon press against the commutator. The brushes make sliding contact with successive commutator segments as the rotator turns, supplying current to the rotor. The windings on the rotor are connected to the commutator segments. The commutator reverses the current direction in the rotor windings with each half turn (180°), so

Colenso Power Station - Misplaced Pages Continue

4158-426: The brakes . Similarly, with rheostatic brakes , energy is recovered by using electric motors as generators but is immediately dissipated as heat in resistors . In addition to improving the overall efficiency of the vehicle, regeneration can significantly extend the life of the braking system. This is because the traditional mechanical parts like discs, calipers, and pads – included for when regenerative braking alone

4257-451: The traction motor connections are altered to turn them into electrical generators. The motor fields are connected across the main traction generator (MG) and the motor armatures are connected across the load. The MG now excites the motor fields. The rolling locomotive or multiple unit wheels turn the motor armatures, and the motors act as generators, either sending the generated current through onboard resistors ( dynamic braking ) or back into

4356-416: The 1740s. The theoretical principle behind them, Coulomb's law , was discovered but not published, by Henry Cavendish in 1771. This law was discovered independently by Charles-Augustin de Coulomb in 1785, who published it so that it is now known by his name. Due to the difficulty of generating the high voltages they required, electrostatic motors were never used for practical purposes. The invention of

4455-672: The 1950s and is exemplified in such systems as the Zytek , Flybrid, Torotrak and Xtrac used in F1. Differential based systems also exist such as the Cambridge Passenger/Commercial Vehicle Kinetic Energy Recovery System (CPC-KERS). Xtrac and Flybrid are both licensees of Torotrak's technologies, which employ a small and sophisticated ancillary gearbox incorporating a continuously variable transmission (CVT). The CPC-KERS

4554-543: The 2020s, most vehicles equipped with regenerative braking can completely halt reasonably quickly in One Pedal Driving mode. Some car models do not illuminate the braking light when engaging in regenerative braking, leading to safety concerns. Most regulations do not mandate the illumination of a braking light when the vehicle decelerates through regenerative braking. The One Pedal Driving (OPD) mode also lead to concerns over sudden unintended acceleration (SUA), as

4653-600: The 274 km section of the Glencoe – Pietermaritzburg part of the Durban-Johannesburg railway – the area that had the greatest gradients, and also the area that was closest to the coalfields of the Glencoe region. Power generated at Colenso was distributed at 88,000 volts to twelve substations where it was converted to 6,600 volts and then to 3,000 volts DC current by synchronous motor generators for use by

4752-459: The FOTA teams agreeing to the use of KERS devices once more, meant that KERS returned for the 2011 season. This is still optional as it was in the 2009 season; in the 2011 season 3 teams elected not to use it. For the 2012 season , only Marussia and HRT raced without KERS, and by 2013, with the withdrawal of HRT, all 11 teams on the grid were running KERS. In the 2014 season , the power output of

4851-506: The KERS controller for power and battery management. Bosch also offers a range of electric hybrid systems for commercial and light-duty applications. Automakers including Honda have been testing KERS systems. At the 2008 1,000 km of Silverstone , Peugeot Sport unveiled the Peugeot 908 HY , a hybrid electric variant of the diesel 908, with KERS. Peugeot planned to campaign the car in

4950-499: 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 the motor controller automatically began battery charging when the brake pedal was applied. Many modern hybrid and electric vehicles use this technique to extend

5049-582: The Lauffen waterfall on the Neckar river. The Lauffen power station included a 240 kW 86 V 40 Hz alternator and a step-up transformer while at the exhibition a step-down transformer fed a 100-hp three-phase induction motor that powered an artificial waterfall, representing the transfer of the original power source. The three-phase induction is now used for the vast majority of commercial applications. Mikhail Dolivo-Dobrovolsky claimed that Tesla's motor

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5148-529: The MGU-K (The replacement of the KERS and part of the ERS system that also includes a turbocharger waste heat recovery system) was increased from 60 kW to 120 kW and it was allowed to recover 2 mega- joules per lap. This was to balance the sport's move from 2.4-litre V8 engines to 1.6-litre V6 engines. The fail-safe settings of the brake-by-wire system that now supplements KERS came under examination as

5247-553: The Metropolitan and District Lines. What are described as dynamic brakes (" rheostatic brakes " in British English) on electric traction systems, unlike regenerative brakes, dissipate electric energy as heat rather than using it, by passing the current through large banks of resistors . Vehicles that use dynamic brakes include forklift trucks , diesel-electric locomotives , and trams . This heat can be used to warm

5346-474: The Orange Free State. Between 1944 and 1959 a series of new generators were commissioned, resulting in the power station's capacity being increased to 160 MW. However, in the 1960s, changes in technology led to a change in the economics of power production. New power stations such as Ingagane were built at the coal fields themselves and the use 400 kVA power lines from 1972 onwards reduced

5445-454: The continued use of the Colenso power station was no longer economically viable. The original part of the power station was decommissioned in 1970 and the 1944-1959 extensions in 1985. The power station's cooling towers remain standing to this day. In recent years a concerted effort has been in process to re-establish a new, larger, independent base load power station near the original site of

5544-470: The cost of transporting electricity. In the early 1980s Eskom initiated a major development programme: in 1980 new large power stations at Kriel (3,000 MW), Hendrina (2,000 MW) and Camden (1,600 MW) had been commissioned and in the next few years a number of other new power stations gave South Africa a surplus of generating capacity and many of the 1960s vintage power stations (including Colenso's refurbishment) had become uneconomic. This meant that

5643-523: The development of DC motors, but all encountered the same battery cost issues. As no electricity distribution system was available at the time, no practical commercial market emerged for these motors. After many other more or less successful attempts with relatively weak rotating and reciprocating apparatus Prussian/Russian Moritz von Jacobi created the first real rotating electric motor in May 1834. It developed remarkable mechanical output power. His motor set

5742-478: The developments by Zénobe Gramme who, in 1871, reinvented Pacinotti's design and adopted some solutions by Werner Siemens . A benefit to DC machines came from the discovery of the reversibility of the electric machine, which was announced by Siemens in 1867 and observed by Pacinotti in 1869. Gramme accidentally demonstrated it on the occasion of the 1873 Vienna World's Fair , when he connected two such DC devices up to 2 km from each other, using one of them as

5841-404: The driver could confuse the accelerator as the brake in stressful situations when the latter is seldomly used during OPD driving. Electric motors , when used in reverse, function as generators and will then convert mechanical energy into electrical energy. Vehicles propelled by electric motors use them as generators when using regenerative braking, braking by transferring mechanical energy from

5940-508: The electric energy produced in the US. In 1824, French physicist François Arago formulated the existence of rotating magnetic fields , termed Arago's rotations , which, by manually turning switches on and off, Walter Baily demonstrated in 1879 as in effect the first primitive induction motor . In the 1880s many inventors were trying to develop workable AC motors because AC's advantages in long-distance high-voltage transmission were offset by

6039-576: The electric grid, provided for electric distribution to trolleys via overhead wires and the trolley pole, and provided control systems for electric operations. This allowed Sprague to use electric motors to invent the first electric trolley system in 1887–88 in Richmond, Virginia , the electric elevator and control system in 1892, and the electric subway with independently powered centrally-controlled cars. The latter were first installed in 1892 in Chicago by

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6138-474: The electrochemical battery by Alessandro Volta in 1799 made possible the production of persistent electric currents. Hans Christian Ørsted discovered in 1820 that an electric current creates a magnetic field, which can exert a force on a magnet. It only took a few weeks for André-Marie Ampère to develop the first formulation of the electromagnetic interaction and present the Ampère's force law , that described

6237-423: The energy is stored chemically in a battery , electrically in a bank of capacitors , or mechanically in a rotating flywheel . Hydraulic hybrid vehicles use hydraulic motors to store energy in the form of compressed air . In a hydrogen fuel cell powered vehicle, the electrical energy generated by the motor is stored chemically in a battery, similar to battery and hybrid electric vehicles. Regenerative braking

6336-490: The factory raced with a secret kinetic energy recovery system (KERS) fitted to Tommy Koyama 's motorcycle during the 2008 season-ending 125cc Valencian Grand Prix . This was against the rules, so they were banned from doing it afterwards. Automobile Club de l'Ouest , the organizer behind the annual 24 Hours of Le Mans event and the Le Mans Series , was "studying specific rules for LMP1 that will be equipped with

6435-472: The first device to contain the three main components of practical DC motors: the stator , rotor and commutator. The device employed no permanent magnets, as the magnetic fields of both the stationary and revolving components were produced solely by the currents flowing through their windings. The first commutator DC electric motor capable of turning machinery was invented by English scientist William Sturgeon in 1832. Following Sturgeon's work,

6534-586: The inability to operate motors on AC. The first alternating-current commutatorless induction motor was invented by Galileo Ferraris in 1885. Ferraris was able to improve his first design by producing more advanced setups in 1886. In 1888, the Royal Academy of Science of Turin published Ferraris's research detailing the foundations of motor operation, while concluding at that time that "the apparatus based on that principle could not be of any commercial importance as motor." Possible industrial development

6633-644: The load are exerted beyond the outermost bearing, the load is said to be overhung. The rotor is supported by bearings , which allow the rotor to turn on its axis by transferring the force of axial and radial loads from the shaft to the motor housing. A DC motor is usually supplied through a split ring commutator as described above. AC motors' commutation can be achieved using either a slip ring commutator or external commutation. It can be fixed-speed or variable-speed control type, and can be synchronous or asynchronous. Universal motors can run on either AC or DC. DC motors can be operated at variable speeds by adjusting

6732-546: The magnet, showing that the current gave rise to a close circular magnetic field around the wire. Faraday published the results of his discovery in the Quarterly Journal of Science , and sent copies of his paper along with pocket-sized models of his device to colleagues around the world so they could also witness the phenomenon of electromagnetic rotations. This motor is often demonstrated in physics experiments, substituting brine for (toxic) mercury. Barlow's wheel

6831-416: The main reasons that not all cars used KERS immediately is because it raises the car's center of gravity, and reduces the amount of ballast that is available to balance the car so that it is more predictable when turning. FIA rules also limit the exploitation of the system. The concept of transferring the vehicle's kinetic energy using flywheel energy storage was postulated by physicist Richard Feynman in

6930-1363: The motor's shaft. An electric generator is mechanically identical to an electric motor, but operates in reverse, converting mechanical energy into electrical energy. Electric motors can be powered by direct current (DC) sources, such as from batteries or rectifiers , or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. Electric motors may be classified by considerations such as power source type, construction, application and type of motion output. They can be brushed or brushless , single-phase , two-phase , or three-phase , axial or radial flux , and may be air-cooled or liquid-cooled. Standardized motors provide power for industrial use. The largest are used for ship propulsion, pipeline compression and pumped-storage applications, with output exceeding 100 megawatts . Applications include industrial fans, blowers and pumps, machine tools, household appliances, power tools, vehicles, and disk drives. Small motors may be found in electric watches. In certain applications, such as in regenerative braking with traction motors , electric motors can be used in reverse as generators to recover energy that might otherwise be lost as heat and friction. Electric motors produce linear or rotary force ( torque ) intended to propel some external mechanism. This makes them

7029-414: The motors rotate with the supply frequency both when driving and braking. Kinetic energy recovery systems (KERS) were used for the motor sport Formula One 's 2009 season , and are under development for road vehicles. KERS was abandoned for the 2010 Formula One season , but re-introduced for the 2011 season . By 2013 , all teams were using KERS with Marussia F1 starting use for the 2013 season. One of

7128-499: The old Colenso power station. With a substantial coal resource discovered near the town and with the gradual liberalising of the South African electric power generation industry, a modern coal technology power generation unit is planned. Regenerative braking Regenerative braking is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy or potential energy into

7227-485: The point of use, and improving power transmission efficiency. Electric motors applied in agriculture eliminated human and animal muscle power from such tasks as handling grain or pumping water. Household uses (like in washing machines, dishwashers, fans, air conditioners and refrigerators (replacing ice boxes ) of electric motors reduced heavy labor in the home and made higher standards of convenience, comfort and safety possible. Today, electric motors consume more than half of

7326-485: The production of mechanical force by the interaction of an electric current and a magnetic field. Michael Faraday gave the first demonstration of the effect with a rotary motion on 3 September 1821 in the basement of the Royal Institution . A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet (PM) was placed. When a current was passed through the wire, the wire rotated around

7425-674: The railways. The power station was sold to the Electricity Supply Commission ( Eskom ) in January 1927. It used coal that was brought in by rail from the coalfields of North Natal and water from the Tugela. It continued to be the provider of electrical power for the railways which by 1937 consisted of the whole of the Natal section of the Durban – Johannesburg line (516 route km) and the 229 km spur to Bethlehem in

7524-410: The range of the battery pack, especially those using an AC drive train (most earlier designs used DC power). An AC/DC rectifier and a very large capacitor may be used to store the regenerated energy, rather than a battery. The use of a capacitor allows much more rapid peak storage of energy, and at higher voltages. Mazda used this system in some 2018 cars, where it is branded i-ELOOP. During braking,

7623-457: The rolling direction. Braking effort is proportional to the product of the magnetic strength of the field windings, multiplied by that of the armature windings. Savings of 17%, and less wear on friction braking components, are claimed for British Rail Class 390s . The Delhi Metro reduced the amount of carbon dioxide ( CO 2 ) released into the atmosphere by around 90,000 tons by regenerating 112,500 megawatt hours of electricity through

7722-428: The rotor and stator ferromagnetic cores have projections called poles that face each other. Wire is wound around each pole below the pole face, which become north or south poles when current flows through the wire. In a nonsalient-pole (distributed field or round-rotor) motor, the ferromagnetic core is a smooth cylinder, with the windings distributed evenly in slots around the circumference. Supplying alternating current in

7821-465: The rotor and the stator. The product between these two fields gives rise to a force and thus a torque on the motor shaft. One or both of these fields changes as the rotor turns. This is done by switching the poles on and off at the right time, or varying the strength of the pole. Motors can be designed to operate on DC current, on AC current, or some types can work on either. AC motors can be either asynchronous or synchronous. Synchronous motors require

7920-402: The rotor, which moves, and the stator, which does not. Electrically, the motor consists of two parts, the field magnets and the armature, one of which is attached to the rotor and the other to the stator. Together they form a magnetic circuit . The magnets create a magnetic field that passes through the armature. These can be electromagnets or permanent magnets . The field magnet is usually on

8019-493: 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. Following

8118-454: The stator and the armature on the rotor, but these may be reversed. The rotor is the moving part that delivers the mechanical power. The rotor typically holds conductors that carry currents, on which the magnetic field of the stator exerts force to turn the shaft. The stator surrounds the rotor, and usually holds field magnets, which are either electromagnets (wire windings around a ferromagnetic iron core) or permanent magnets . These create

8217-435: The stator in plastic resin to prevent corrosion and/or reduce conducted noise. An air gap between the stator and rotor allows it to turn. The width of the gap has a significant effect on the motor's electrical characteristics. It is generally made as small as possible, as a large gap weakens performance. Conversely, gaps that are too small may create friction in addition to noise. The armature consists of wire windings on

8316-762: The steep and dangerous Surami Pass . In Scandinavia the Kiruna to Narvik electrified railway, known as Malmbanan on the Swedish side and Ofoten Line on the Norwegian, 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

8415-400: The supply (regenerative braking). Compared to electro-pneumatic friction brakes, braking with the traction motors can be regulated faster improving the performance of wheel slide protection . For a given direction of travel, current flow through the motor armatures during braking will be opposite to that during motoring. Therefore, the motor exerts torque in a direction that is opposite from

8514-406: The torque applied to the rotor is always in the same direction. Without this reversal, the direction of torque on each rotor winding would reverse with each half turn, stopping the rotor. Commutated motors have been mostly replaced by brushless motors , permanent magnet motors , and induction motors . The motor shaft extends outside of the motor, where it satisfies the load. Because the forces of

8613-628: The use of regenerative braking systems between 2004 and 2007. It was expected that the Delhi Metro would reduce its emissions by over 100,000 tons of CO 2 per year once its phase II was complete, through the use of regenerative braking. Electricity generated by regenerative braking may be fed back into the traction power supply; either offset against other electrical demand on the network at that instant, used for head end power loads, or stored in lineside storage systems for later use. A form of what can be described as regenerative braking

8712-543: The vehicle interior, or dissipated externally by large radiator -like cowls to house the resistor banks. General Electric's experimental 1936 steam turbine locomotives featured true regeneration. These two locomotives ran the steam water over the resistor packs, as opposed to air cooling used in most dynamic brakes. This energy displaced the oil normally burned to keep the water hot, and thereby recovered energy that could be used to accelerate again. The main disadvantage of regenerative brakes when compared with dynamic brakes

8811-663: The voltage applied to the terminals or by using pulse-width modulation (PWM). AC motors operated at a fixed speed are generally powered directly from the grid or through motor soft starters . AC motors operated at variable speeds are powered with various power inverter , variable-frequency drive or electronic commutator technologies. The term electronic commutator is usually associated with self-commutated brushless DC motor and switched reluctance motor applications. Electric motors operate on one of three physical principles: magnetism , electrostatics and piezoelectricity . In magnetic motors, magnetic fields are formed in both

8910-572: The wheels to an electrical load. In 1886 the Sprague Electric Railway & Motor Company, founded by Frank J. Sprague , introduced two important inventions: a constant-speed, non-sparking motor with fixed brushes, and regenerative braking. Early examples of this system in road vehicles were the front-wheel drive conversions of horse-drawn cabs by Louis Antoine Krieger in Paris in the 1890s. The Krieger electric landaulet had

9009-406: The winding, further increasing the efficiency. In 1886, Frank Julian Sprague invented the first practical DC motor, a non-sparking device that maintained relatively constant speed under variable loads. Other Sprague electric inventions about this time greatly improved grid electric distribution (prior work done while employed by Thomas Edison ), allowed power from electric motors to be returned to

9108-431: The windings creates poles in the core that rotate continuously. A shaded-pole motor has a winding around part of the pole that delays the phase of the magnetic field for that pole. A commutator is a rotary electrical switch that supplies current to the rotor. It periodically reverses the flow of current in the rotor windings as the shaft rotates. It consists of a cylinder composed of multiple metal contact segments on

9207-508: Was an early refinement to this Faraday demonstration, although these and similar homopolar motors remained unsuited to practical application until late in the century. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils . After Jedlik solved the technical problems of continuous rotation with the invention of the commutator , he called his early devices "electromagnetic self-rotors". Although they were used only for teaching, in 1828 Jedlik demonstrated

9306-406: Was announced that Freescale Semiconductor would collaborate with McLaren Electronic Systems to further develop its KERS for McLaren's Formula One car from 2010 onwards. Both parties believed this collaboration would improve McLaren's KERS system and help the system filter down to road car technology. Toyota has used a supercapacitor for regeneration on a Supra HV-R hybrid race car that won

9405-449: Was envisioned by Nikola Tesla , who invented independently his induction motor in 1887 and obtained a patent in May 1888. In the same year, Tesla presented his paper A New System of Alternate Current Motors and Transformers to the AIEE that described three patented two-phase four-stator-pole motor types: one with a four-pole rotor forming a non-self-starting reluctance motor , another with

9504-458: Was found not to be suitable for street cars, but Westinghouse engineers successfully adapted it to power a mining operation in Telluride, Colorado in 1891. Westinghouse achieved its first practical induction motor in 1892 and developed a line of polyphase 60 hertz induction motors in 1893, but these early Westinghouse motors were two-phase motors with wound rotors. B.G. Lamme later developed

9603-484: Was given an electric shock when he touched Christian Klien 's KERS-equipped car during a test at the Jerez circuit . With the introduction of KERS in the 2009 season, four teams used it at some point in the season: Ferrari , Renault , BMW , and McLaren . During the season, Renault and BMW stopped using the system. McLaren Mercedes became the first team to win a F1 GP using a KERS equipped car when Lewis Hamilton won

9702-438: Was not practical because of two-phase pulsations, which prompted him to persist in his three-phase work. The General Electric Company began developing three-phase induction motors in 1891. By 1896, General Electric and Westinghouse signed a cross-licensing agreement for the bar-winding-rotor design, later called the squirrel-cage rotor . Induction motor improvements flowing from these inventions and innovations were such that

9801-503: Was the first time that KERS contributed directly to a race victory, with second placed Giancarlo Fisichella claiming "Actually, I was quicker than Kimi. He only took me because of KERS at the beginning". Although KERS was still legal in Formula 1 in the 2010 season, all the teams had agreed not to use it. New rules for the 2011 F1 season which raised the minimum weight limit of the car and driver by 20 kg to 640 kg, along with

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