Tractive force calculator pdf

The calculator can be used for imperial and metric units as long as the use of units are consistent. Tractive effort is defined as the force at the rims or the outer edges of the driving wheels of moving trains. Pdf calculation of the traction effort of switching locomotive. A 4,000 hp sd70mac of 20 years later produces 86,000 lbs maximum db force. Maximum rear wheel tractive force from drive torque, frwmax n. Horsepower in automotive terms is the application of a force at a certain speed. Total motor limited tractive force from from both front wheels, ffwmax n. This will be recognized as the sverage boundary shear. What is difference between tractive force and tractive effort. The higher the loco hp generally the higher the maximum db force. This calculator will determine the forces, momentum and physics of a four wheeled vehical driving over various conditions.

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. Vehicle forces for driving up slope equations and calculator. Equations behind the vehicle forces for driving up slope calculator. Measurement of tractive force in the creep region and maximum. Tractive effort and tractive resistance c12 springerlink. This calculator can be used to calculate the resulting force in a toggle joint with arms with equal lengths. Tractive effort te and tractive resistance tr tractive effort te. Tractive force is nothing but the net force present at wheels. The traction parameters involving forces are all normalized by dividing by wd, the dynamic force reaction supporting the wheel or traction device. 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. Jan perner transport faculty, university of pardubice, studentska 95, 532 10.

Total tractive effort is the net horizontal force applied by the drive wheels to the ground. Rr force necessary to overcome rolling resistance lb. Available tractive effort road vehicle performance. For steam locomotives, tractive effort was usually the limitting factor in the size of the train it could pull. To do this we will use the maximum tractive effort calculated in equation 9 which was 100 lbs. This force, which is simply the pull of water on the wetted area, is known as the tractive force chow, 1959 t. Traction can also refer to the maximum tractive force between a body and a surface, as limited by available friction. 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.

As used in mechanical engineering, the term tractive force can either refer to the total traction a. Employ a balance between the shear force mobilizing the sediment and the resisting force depending on the material. From newtons second law using the equation above you can work out the equivalent accelerations to each tractive effort. Take one example i have one vehicle which has weight of 500kg.

In railway engineering, the term tractive effort is often used synonymously with tractive force to describe the pulling or pushing capability of a locomotive. Drive wheel motor torque calculations ufl mae concrete good. What we are going to do now is map out the turning force a sample engine will provide to the wheels throughout the gear, creating what is called a tractive effort graph, which as the name implies shows the amount of traction needed to put the power to the ground without wheel spin. Understanding torque and horsepower with tractive force. The third radius shown in figure 1 is called the torque radius rt. The total axle torque is tractive effort times the wheel radius. A power presizing methodology for electric vehicle. In the main line train, tractive effort is caused by the locomotive, and in a suburban train, it is caused by motor coaches. If the design has two drive wheels, the force applied per drive wheel for straight travel is half of the calculated tte. Acceleration is a measure of how quickly you are gaining or losing speed.

How to calculate traction torque on wheel of automobile. Tractive force steam locomotives calculator fx solver. W weight or vertical force between wheel and surface n, lb f m mass on. In this case, the liquid is storm water and the boundary is the channel surface. For slopes, you will need an additional 100 newton per percent of steepness. At very slow yard speeds only 2 to 3 pounds is needed while increasing to about 5 pounds at higher speeds. When a vehicle is moving up a gradient, the normal force p, in equation 4.

So in this case its wheel torque the rolling radius from cenre of wheel to outer egde of tyre. Tractive effort is a measure of the force that a locomotive can apply to the train it is pulling. Tractive effort versus horsepower trains magazine trains. First, a force of 2 to 5 pounds per ton of train weight is required to move on straight level track. 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. Continuous tractive effort is the tractive force that can be maintained indefinitely, as distinct from the higher tractive effort that can be maintained for a limited period of time before the power transmission system overheats. 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. Road load and tractive force the road load consists of t t i w ro sf ad cr f f f f f 1 the rolling resistance force f ro is produced by the tire flattening at the roadway contact surface. As with power there are different methods of measuring tractive effort.

Shear stress is also occasionally referred to as the tractive force. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. As an approximation, the following formula can be used for a twocylinder locomotive t d 2 s p w. Both can be affected by the softness of the soil surface and are usually determined on a hard surface. Shear stress is the force applied by flowing liquid to its boundary.

F tf is zero for a rearwheeldriven vehicle, whereas f tr is zero for a frontwheeldriven vehicle. Pdf calculation of the traction effort of switching. The tractive force ft in the contact area between the tires of the driven wheels. Calculation of locomotive traction force in transient rolling contact. Calculating tractive effort page 1 locomotives and. A 3,000 hp sd402 may produce a maximum of 10,000 lbs of db force for each axle or 60,000 lbs total. A number that relates to a tractive effort on a dc motor locomotive that the traction motor can obtain indefinitely without overheating. 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. For simulations and calculations a quadratic formula is used to represent. The wheel torque calculated in step five is the total.

Force of vehicles engine maximum value transferable maximum tractive effort define the point at which additional enginegenerated tractive effort is not productive. Tractive force when water flows in a channel, a force is developed that acts in the direction of flow on the channel bed. The changes in the design procedure are those that remove references to allowable velocity procedures and replace them with tractive stress evaluations. F traction effort or force acting on the wheel from the surface n, lb f. Tractive effort is the force needed to simply move the train. W weight or vertical force between wheel and surface n, lb f m mass on the wheel kg, slugs a g acceleration of. Material provided by sachin buddhisagar, copyright 2011. The data points calculated in order to produce a torque diagram may also be used to ascertain the mean or average tractive force produced. The velocity of a locomotive depends on two forces the. See equations dehind this calculator vehicle driving forces equations. In future months design parameters for a diesel and steam locomotive. The tractive effort required to move a train consists of numerous factors, but for most applications only four need to be considered. 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. The maximum permissible traction force that can be applied to the wheels is governed by two things.

Cte is non applicable for an ac traction motor, which use te only. If you double the force but halve the speed again the horsepower is the same. Torque diagrams such as figure 7 clearly illustrate the varying nature of the tractive force produced by a steam locomotive under the theoretical conditions described. Tractive effort curves show how much force the wheels can push forward on the rails with for any given speed. Horsepower and tractive effort the idiots guide to. Put simply, shear stress describes the force of water that is trying to drag the channel surface downstream with it. For tractional torque you have to calculate the traction force requirement by your vehicle. In other words, it is the sum of the tractive force and rolling effort on the road surface. I have calculate the tractional force required to move the vehicle. Tireground adhesion and maximum tractive effort the slip, s, of a tire is usually defined as where v is the translatory speed of the tire center. What is difference between tractive force and tractive. Tractive force for hard, smooth surfaces is a proportional function of weight and the coefficient of friction of the two materials in contact.

The acceleration force is a function of the mass of the vehicle. If you double the speed but halve the force, you are producing the same horsepower. To choose motors capable of producing enough torque to propel the example vehicle, it is necessary to determine the total tractive effort tte. Tractive effort te is the force applied by a locomotive for moving itself and a train. Static loaded radius is more appropriate to use for force or moment calculations. Jan 07, 20 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. Although the new method can be derived from a modification of the shear stress equations, it does not use shear stress explicitly. Tractive effort or tractive force is measured in kilonewtons kn or pounds force lbf where 1 kn 228.

Pdf vehicle tractive force prediction with robust and windupstable. Locomotive tractive effort and power calculations tractive effort calculations. Therefore, tractive effort was more important than horsepower for steam locomotives. The dynamic equation of vehicle motion along the longitudinal direction is expressed by where dvdt is the linear acceleration of the vehicle along the longitudinal. Sep 11, 2017 without any context it is difficult to say how it isnt just a force. Department of agriculture usda prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where. The speed at which both forces are equal is the maximum speed the train can get to on a flat piece of track. Maths help converting tractive effort to torque nm.

Tractive effort and acceleration ce 322 transportation engineering dr. Keep in mind the db force produced is directly related to the number of axles a loco has. The backbone of train simulation physics is the simple equation, fma force mass x acceleration. Chapter 8 threshold channel design 210vineh, august 2007 issued august 2007 the u. Tractive effort is the force available at the area of contact between the rear wheel tyres and the road for a rear wheel driven car. This calculator can be used to calculate the maximum acceleration and minimum accelation time for a car on different surfaces.

Ahmed abdelrahim available tractive effort tractive effort determined by. Although hec15 is recommended for design flows less than 50 ft3sec 1. Car vehicle driving up a slope equation and calculator. Jun 20, 2018 tractive effort is the force available at the area of contact between the rear wheel tyres and the road for a rear wheel driven car. With the three cylinder locos the nsw d5758 class had that, the tractive effort was, d57 class. The tractive force between a car wheel and the surface can be expressed as. Fa m a 3 m gvw g 4 fa acceleration force m mass of the vehicle g acceleration due to gravity9. Adhesion is the grip or force of attachment, produced by. Due to the relationship between power p, velocity v and force f, described as. Morphologic and hydraulic properties of sacramento river between chico landing site e10 and woodson bridge, california 57 iv. 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 efficiency te, usually thought of as percent but used as a ratio in this paper. The document was revised to add background information, examples, and a glossary and to expand the bibliography. The following state equation is obtained if the tractive force f changes as a step function. Army corps of engineers riprap design for flood channels. The total tractive effort tte is the sum of the forces calculated in steps 1, 2, and 3. Above is a tractive effort curve typical of a new electric train. See equations dehind this calculator engineers edge. Maximum rear wheel tractive force from drive torque, frwmax n maximum rear wheel force from drive torque, ffwmax n maximum rear wheel tractive force before slip, frwmumax n maximum front wheel tractive force before slip, ffwmumax n total tractive force generated by both rear wheels, ftr n. An amount of torque distributed to the wheel from differential divided by wheel radius is the tractive effort an. Power is the force needed to run a train at a certain speed.

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