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Locomotive starting with constant power and locomotive starting with constant traction (acceleration) The teacher spoke very fast in class and didn't understand much,
When the constant power starts, P = FV, the speed V increases at the beginning, but f decreases, and the product of the two does not change
How to judge whether the locomotive is a constant power or a constant acceleration?
If the F-1 / V image is a straight line crossing the origin or the P-V image is a straight line parallel to the X axis, it is a constant power start. Generally speaking, car start generally refers to constant acceleration, uniform acceleration start, power gradually increases, and finally reaches the rated power. Car start is the maximum power at the beginning, and the acceleration decreases
Why do locomotives start with constant acceleration and constant power
Constant acceleration starting means that the traction force does not change when starting, because the friction resistance of the car is constant, so the acceleration does not change. At this time, the car will do uniform acceleration motion. If starting with constant power, P does not change, with the increasing speed, the traction force decreases, the acceleration decreases, and the car makes variable acceleration linear motion with the decreasing acceleration
The car starts at rated power and at constant acceleration, which is very confusing
My high school level
P = f (vehicle power) * V
When p is constant, V increases, f decreases, and a decreases. Finally, f = friction, and V is p / friction
Constant a starts, f is constant, and P increases at a constant speed. When p = P increases to the maximum, it is the same as constant P
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