To the scientifically minded trainzer......

[bassist118]

Hi guys

I have been given a small but painful task to undertake (I think I've bitten off more than I can chew...) How do you go about calculating power consumption of electric trains without having to draw from possibly biased information supplied by the train manufacturers and given that the physics is quite different regarding trains because of the lack of friction between wheel and rail....

Have tried googling it but can't quite get my head around the equations and also the fact that wikipedia is a minefield of mis-information.

Thanks all as I know its a bit of a weird question.

:Y:

Andy

 

[alufdufe]

You are talking about the prototype right? If so, I would contact someone like the Illinois Railway Museum, who actually run electric trains, and ask them.

 

[magickmaker]

Let's see if I can type this out. It will read very weird, but I can link you the page I got it from.


Wt=[2.725/0.814(ΣTa x da + ΣTb x db)]+[Pa/0.964 x (Σdc/vc + ΣdD/vD)]

Where:
Wt= Total power energy consumption(kWh)
T = force in tons due to tractive effort (ton)
d = distance traveled in km at that speed range (km)
Pa= power consumption by all auxiliaries (kWh)
A, B, C, D = Acceleration, Balancing, Coasting, and Deceleration stage, respectively.


Wardrop (1989) proposes an electric-power based model to estimate energy consumption. The basic calculation, as shown in this equation requires line voltage, current and motor combination code, etc. The k value is the number of parallel motor circuits. According to equation, this method contains an assumption that energy consumption has a linear relationship with the proportion between actual traction and maximum traction. Eash (1978) and Lee (2000) also use this approach in their models, but each uses different concept to determine voltage or current.

Em=∫ 1/1000 * 3600 * V * Im * k * rtdt = 1 / 3.6 x 10^6 * k * V∫Im * rtDt

Where:
Em =main power energy consumptin (kWh)
V =Voltage (V)
Im =motor current (A)
k =motor combination code, K > 1
rt= T actual/ T max, the proportion between actual traction (T actual) and Maximum traction (T max), 0 < rt < 1
t = operation time (seconds)


http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.101.3548&rep=rep1&type=pdf

Before you ask. I was supposed to go to college on an engineering and physics scholarship, but I dropped out because I got bored. I still tutor local students in trig and physics.

 

[bassist118]

Thankyou that is exactly what I wanted. I've been asked to compare the power usage of the proposed AGV against a lengthened 11 coach Pendolino

Felt like I was banging my head against a wall for several days before posting on this forum.

Thanks again for the great help, can breath a sigh of relief now

:Y::Y:

Andy

Just one more thing does anyone know how much 1 Virgin Pendolino (class 390) coach weigh?? The total weight of the 9 coach consist is 471 metric tonnes.

 

[magickmaker]

Thankyou that is exactly what I wanted. I've been asked to compare the power usage of the proposed AGV against a lengthened 11 coach Pendolino

Felt like I was banging my head against a wall for several days before posting on this forum.

Thanks again for the great help, can breath a sigh of relief now

:Y::Y:

Andy

Just one more thing does anyone know how much 1 Virgin Pendolino (class 390) coach weigh?? The total weight of the 9 coach consist is 471 metric tonnes.

If you're looking for an average, just take the total weight and divide it by the number of coaches in the consist.

 

[bassist118]

If you're looking for an average, just take the total weight and divide it by the number of coaches in the consist.

Yep I thought of that but I want the info to be more accurate. I wont go into the reasons why coz last time I did that the thread got deleted lol

Cheers anyways

:Y:

Andy

 

[WileeCoyote]

Or you can always just look at the electric meter fitted on the locomotive/MU if it's fitted with one.

WileeCoyote