When moving up in the slope the drive has to produce tractive effort to overcome the force due to gravity. The total axle torque is tractive effort times the wheel radius. Starting vs continuous tractive effort trains magazine. Remember also that this gives the power at the rims of the driving wheels and not at the rear coupler of the locomotive where it counts. Or electric traction means a locomotion in which the driving force is obtained from electric motors. Force of vehicles engine maximum value transferable maximum tractive effort define the point at which additional enginegenerated tractive effort is not productive. The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered. I work for eversholt rail a train leasing company that owns about a. Available tractive effort road vehicle performance. Multitrain modeling and simulation integrated with traction power supply solver using simplified newtonraphson method thanatchai kulworawanichpong 0 0 school of electrical engineering, institute of engineering, suranaree university of technology, nakhon ratchasima 30000, thailand multitrain modeling and simulation plays a vital role in railway electrification during.
As used in mechanical engineering, the term tractive force can either refer to the total traction a vehicle exerts on a surface, or the amount of the total traction that. Also, the common expression is tractive effort, not traction effort. Control systems and tractive effort ztr control systems, llc. First, a force of 2 to 5 pounds per ton of train weight is required to move on straight level track.
On the left of the horizontal panel is a set of buttons for controlling the cab, console, wc and bogie lighting. Trains special issue locomotives, november 2006 train, september 1999 diesel locomotives, by greg mcdonnell model railroader, november 2004 ge transportation group, 2007 archives. Series commutator motor, therefore it requires regular maintenance. Tractive effort and train resistance horsepower friction scribd.
Tractive force calculation for a vehicle tractive force or tractive effort or traction is the force applied between the tire and road surface to move a car or any vehicle for that matter. A locomotives tractive effort at all speeds is limited by its adhesive weight and the available coefficient of adhesion between wheel and rail, as illustrated in the above diagram and as discussed in more detail on the adhesion page of this website the maximum speed that a locomotive can attain with any given train occurs when the locomotives drawbar tractive. This may seem like a trivial distinction, but to a physicist power and force are very different quantities. The inner twothirds of the wing are cambered when the wing is extended, and are concerned with lifting effort in unsoarable air and with lifting and tractive effort in soarable air. Traction motors and are appended at appendix 1 and 3.
The traction force ft required at the drive wheels is made up of the driving. Which basically means, from the blueprints, that is the effort it should be capable of producing. If a cross over the tractive effort curve would appear for the next gear by remaining in gear until maximum rpm, then a small, roughly triangular shaped section would be cut out of the available area every time when gear is changed. The most important source to provide traction mechanics train, grade, curve and acceleration resistance power in the locomotive is traction motor. Based on the vehicle desired performances, the electric motor optimal power can.
The speed at which both forces are equal is the maximum speed the train can get to on a flat piece of track. Tractive effort and resistance to motion tractive effort resistance to motion i have extended the speed range on the graph to show the point where the resistance to motion gets larger than the tractive effort. Tractive effort definition of tractive effort by merriam. Steerable trucks, controlled traction effortreference sources. I need to know exactly what the difference is between traction and tractive force. On older dieselelectric locomotives, horsepower at the rail was assumed to be about 82% of the prime movers output. If the direction of nose is towards the direction of motion of loco, the nose presses upward on bogie and equal pressure acts. Physical factors in tyre traction k c ludema department of mechanical engineering, university of michigan, ann arbor. So if they could handle the tractive effort of 80 000, then the engineer should not drive below 9. Tractive effort and tractive resistance c12 springerlink. Macmillan vi rolling motion resistance, r is the force opposing motion of the wheel that arises from the nonrecoverable energy expended in deforming the surface and wheel.
Pdf a common feature of all engines with internal combustion is the need for a gearbox. Total tractive effect required for accelerating the train on a level track. The maximum permissible traction force that can be applied to the wheels is governed by two things. Pdf on jan 1, 2012, anton rassolkin and others published calculation of the traction effort of switching locomotive find, read and cite all the research you. Tractive effort curve mathematics in education and industry. Tractive effort, curving and surface damage of rails.
The professional twomonthly magazine of rail transport. The car has a mass of 4,000kg and the resistance to motion is 400n determine. There is a great interest in data on the tractive coefficient for a particular tyre on a particular road. The magnitude and direction of these forces are calculated for equilibrium curving of a conventional twoaxle bogie in curves of 6001800 m radius, both without traction and for a level of tractive effort of 0. On higher speed vehicles friction in drive components may warrant the addition of 10%15% to the total tractive effort to ensure acceptable vehicle performance. Tractive effort definition is the force in pounds exerted by powered equipment as a locomotive as measured for statistical purposes at the rim of the driving wheels. Traction and curving are the principal causes of high tangential forces between railway rails and wheels. As used in mechanical engineering, the term tractive force can either refer to the total traction a vehicle exerts on a surface, or the amount of the total traction that is parallel to the direction of motion in railway engineering, the term tractive effort is often used synonymously with tractive force to describe the pulling or pushing capability of a locomotive. As with power there are different methods of measuring tractive effort. Cte is non applicable for an ac traction motor, which use te only. Acceleration is a measure of how quickly you are gaining or losing speed. I can find definitions of traction but nothing really on tractive force.
A number that relates to a tractive effort on a dc motor locomotive that the traction motor can obtain indefinitely without overheating. Determination of traction characteristics of diesel. The traction threshold speed, where tractive effort is exactly high enough to make full use of engine power, can be calculated by solving for vpft, where ft is tractive effort, p power, and v velocity in ms kph3. A wheel will have different traction on different surfaces, as, the coefficient. The tractive force between a car wheel and the surface can be expressed as. It is convenient to consider this force as acting in the horizontal direction. If the rear wheels of the vehicle in the figure are driven with no slip taking place between the tires and the level road surface, the wheel force or the tractive effort te is equal to the torque at the driven wheels t w divided by the rolling radius or effective radius r w. Tractive effort or tractive force is measured in kilonewtons kn or pounds force lbf where 1 kn 228.
The maximum traction effort co uld be calculated by 9 and 10 with respect to changing of the frictions forces with different atmosphere conditions dr y and wet surfaces. There are many advantages of electric traction over other forms. Tractive effort te is the force applied by a locomotive for moving itself and a train. Three cylinder locos are worked out differently from memory. Traction, or tractive force, is the force used to generate motion between a body and a tangential surface, through the use of dry friction, though the use of shear force of the surface is also commonly used traction can also refer to the maximum tractive force between a body and a surface, as limited by available friction. Tractive effort te and tractive resistance tr tractive effort te. Horsepower and tractive effort the idiots guide to.
Pdf for the complex simulation of dynamic behaviour of a locomotive in connection with drive dynamics and traction control, large. The ztr control systems and tractive effort solutions are designed to improve the performance, reliability and availability of existing locomotive fleets. This locomotive develops,000 pounds of tractive effort. A power presizing methodology for electric vehicle traction motors bekheira tabbache1,2, sofiane djebarri2, abdelaziz kheloui1 and mohamed benbouzid2 abstractthis paper proposes a methodology for presizing the power of an electric vehicle traction motor. Someone more experienced then i with steam may want to correct me here, but the forlmula you gave is for what would be known as the rated tractive effort. Thus the mechanism of the locomotives working, both in traction and. The continuous tractive effort would be determined by how much electricity traction motors could handle before burning up.
Pdf calculation of the traction effort of switching. Nor has there been an effort to determine alternatives to high friction. F traction effort or force acting on the wheel from the surface n, lb f. Calculating tractive force using two methods physics forums. Vehicle dynamics calculation tractive effort of a car. Pdf calculation of the traction effort of switching locomotive. The tractive effort required to overcome the force due to gravity. Pound force applied to the rear coupler to pull a train. Protections towards wheel slip and slid lies with its early detection and reduction of tractive effort and braking effort respectively within least possible time.
The backbone of train simulation physics is the simple equation, fma force mass x acceleration. To do this we will use the maximum tractive effort calculated in equation 9 which was 100 lbs. Locomotive tractive effort and power calculations tractive effort calculations. Tractive motor is a class of electric motor which has the characteristics to match the load requirement of traction such as high starting tractive effort and selfcorrective action with variable. It seems some locomotives have higher starting numbers and lower continuous numbers. Calculating tractive effort for steam locomotives when modeling a set of train vehicles, an important information needed for the dynamics of a locomotive is max tractive effort te, resp max te, which is determining the ability of a locomotive to pull up a train. Influence of locomotive tractive effort on the forces. The tractive force ft in the contact area between the tires of the driven wheels. The total tractive effort tte is the sum of the forces calculated in steps 1, 2, and 3.
Complete details of user programmable parameters are listed at clause no. Gps tracking on smartphone for your pet directly from the manufacturer no. Tractive effort and acceleration ce 322 transportation engineering dr. Tractive effort and train resistance free download as pdf file. Calculating tractive effort page 1 locomotives and. Ahmed abdelrahim available tractive effort tractive effort determined by. The issue of protection towards wheel slip lies with traction wheels only i. Above that speed, the locomotive doesnt have enough power to generate that much force, and is now following the formula fpv. Pdf influence of locomotive tractive effort on the forces between. Traction can be defined as the friction between a drive wheel and the surface it moves upon. Dieselelectric traction has the following advantages. A car accelerates 1800m down an incline of 1 in 4 at 0. This is in contrast to power, which is a measure of the amount of, well, power.
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