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Traction can also refer to the maximum tractive force between a body and a surface, as limited by available friction; when this is the case, traction is often expressed as the ratio of the maximum tractive force to the normal force and is termed the coefficient of traction (similar to coefficient of friction).
The term tractive effort is often qualified as starting tractive effort, continuous tractive effort and maximum tractive effort.These terms apply to different operating conditions, but are related by common mechanical factors: input torque to the driving wheels, the wheel diameter, coefficient of friction (μ) between the driving wheels and supporting surface, and the weight applied to the ...
To establish the "largest" category, several factors take precedence: overall weight, which gives traction over driving axles; size (length and height of engine itself); and power, which may be in terms of raw horsepower, tractive effort, available power at axles (shaft horsepower) or, in the case of steam locomotives, available steam on a ...
It is shown that for a passenger car, when the tractive force is about 40% of the maximum traction, the slip resistance is almost equal to the basic rolling resistance (hysteresis loss). But in case of a tractive force equal to 70% of the maximum traction, slip resistance becomes 10 times larger than the basic rolling resistance. [1]
A locomotive with a factor of adhesion much lower than 4 would be highly prone to wheelslip, although some 3-cylinder locomotives, such as the SR V Schools class, operated with a factor of adhesion below 4 because the traction force at the wheel rim does not fluctuate as much. Other factors affecting the likelihood of wheelslip include wheel ...
Another important factor when traction motors are designed or specified is operational speed. The motor armature has a maximum safe rotating speed at or below which the windings will stay safely in place. Above this maximum speed centrifugal force on the armature will cause the windings to be thrown outward.
Coulomb friction theory says that the maximum horizontal force developed should be proportional to the vertical load on the tire. In practice, the maximum horizontal force Fy that can be generated is proportional, roughly, to the vertical load Fz raised to the power of somewhere between 0.7 and 0.9, typically.
3 Force diagrams. 2 comments. ... 6 Proposed merge into Traction (engineering) 1 comment. 7 Continuous tractive effort. 4 comments. 8 Aerodynamic drag. 1 comment. 9 ...