Electric Traction Motor Research Articles

The effect of iron powders on the utilization of permanent magnet materials in advanced motors

The properties that may be obtained in an iron powder/epoxy resin compact are discussed, and the application of this material as wedges in the armature of an axial-field d.c. machine are described. The effect of the wedge parameters on the design and performance of the machine has been studied, particularly considering the non-uniform flux density across the active diameter in a wedge. Using an electric vehicle traction motor as an example, it is shown that considerable savings in permanent magnet material are achieved by introducing wedges into the previously ironless armature, being as high as 74% with SmCo <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</inf> magnets.

Electrical systems for hybrid vehicles

This paper is a digest of the electrical system section of a report [8] on the feasibility of using a hybrid heat engine/electrical propulsion system as a means of reducing exhaust emissions from street-operated vehicles. The electrical system is composed of an electric traction motor, a generator, control system, and batteries. Batteries are not covered in this paper, but the remainder of the items will be treated here. First, the electrical system parameters or characteristics that have the greatest impact on the total system are considered; next, details of the advantages and disadvantages of various approaches are summarized; and, finally, development efforts are recommended.

Possibilities for the Fuel Cell in the Passenger Car

The fuel cell is naturally attractive as a potential power source because of its direct production of electricity from fuel, quiet operation, and relatively high efficiency. Coupled with an electric traction motor, the fuel-cell battery may be a suitable power plant for passenger cars. This study indicates that with fuel cells having such outputs as are at present considered possible and with modern traction motors, fuel battery/electric cars could not match the performances of modern gasoline-engine cars unless they were very heavy. It is apparent that developments must continue in the direction of lightweight cells with higher outputs, lightweight traction motors, and possibly high-speed transmissions (including hydro-mechanical transmissions) if fuel battery/ electric cars are to become a practical possibility. These developments appear to be possible and could result in a fuel battery car with several advantages, including reduced fuel consumption. (The reduction could be appreciable if hydrocarbon fuels were used.) This appears to be the picture today, though further improvements to gasoline engines could whittle away the expected advantages of fuel cells.

Dynamic Loads on the Gears of Electric Traction Motors Passing over a Rail Joint

The movements of a pair of wheels and axle with and without an electric traction motor passing over a rail joint are investigated. The track is assumed to be resiliently supported and two basic idealized types of joint are considered. In the case of there being a traction motor on the axle, the rotating mass of the armature is regarded as a separate mass resiliently connected to the unsprung masses of the wheels and motor body and the dynamic gear loads are calculated. It is shown that further approximation of actual conditions was possible by a combination of the basic types of rail joint. A concrete example is evaluated and it is seen that the tooth loads are greater with a limited amount of resilience than with an ideally rigid drive, the maximum occurring in the region of the inherent structural resilience of a normal ‘non-resilient’ gear drive. Gear-tooth separation due to dynamic actions is investigated and it is found that the gear loads normally attending such separation are not excessive.

An interurban becomes a railroad

One of the most important advances in rail transportation after the turn of the century was the introduction of electric traction motors for passenger train service. This boom started a crisscross of short interurban electric lines throughout the country with the idea in mind of reaching out and covering more territory. At the time of this boom there were two trends of thought in the traction field - alternating current and direct current.

Economic Evaluation Fuel and Energy Sources for Railway Motive Power

The trend towards widespread utilization of diesel-electric motive power in main-line operations continues unabated with some authorities predicting complete dieselization in the relatively near future. There can be no denying the physical superiority of diesel-electric locomotives over the fast disappearing steam locomotives that have dominated the American motive power scene for over 100 years. There are, however, economic questions of some importance raised by the phenomenal speed with which the change-over is being accomplished and the consequent demand imposed on the nation's middle distillate capacity and the petroleum resources upon which this capacity depends. Locomotives with electric traction motors are probably here for the long pull, but there may be reason to believe that the electrical energy to supply their traction motors can be produced at lower cost in ways other than with diesel-electric prime movers. Under certain circumstances of petroleum product demand and supply the gas-turbine electric locomotive may be found to have an economic justification. Similarly, the trolley-electric locomotive can undoubtedly be justified in situations where hydroelectric, and perhaps other low cost electric generating facilities create a competitive price differential sufficient to overcome the initial cost handicap occasioned in providing the fixed facilities required to bring energy to the pantographs of trolley-electric locomotives. In the Pacific Northwest, for example, it can be demonstrated that on the basis of present prices of electric energy and diesel fuel the extra investment required for operation of trolley-electric locomotives can be recovered from operating savings in about ten years.

The Hammer-Blow with Axle-Hung Electric Traction Motors

The Hammer-Blow with Axle-Hung Electric Traction Motors

The choice of electric traction-motor equipment by the method of similar speed/time curves

The author describes a method of determining rapidly what the characteristics and ratings of an electric traction motor must be for satisfactory operation under any particular service conditions which may be specified.The method involves the construction in advance of a set of general curves applicable to a particular class of service. The assumptions made in order to bring these curves into accord with observed practice in railway, tramway, and trolley-bus service, are fully described, and the construction of one set of curves is followed through in detail, the necessary calculations being also tabulated.Four sets of curves are shown, and the method of using them is explained; several typical examples are worked out to demonstrate the type of information which can quickly be obtained by the use of the curves.