Railway Electric Effect On Body

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 We could hear the sound (Corona) of electric in Bakirkoy TEK High Voltage Transformer Center. Well, why we can hear the sound of electric? Corona is ionization of surrounding air around the cable. Electric is lost as heat, sound, and light. What is electric shock for human body? Voltage difference whose person contact with. So, it needs to two polar area which have potential differences. What difference between current and voltage according to human body? Voltage gives shock, whereas current kills!. How we may calculate voltage and current? It depends on resistance, so V (Voltage) = I (Current) * R (Resistance) What about human body resistance and conductivity? It depends on skin type (hard or soft), contact point, wetness, veins and blood. Salty sweat, underneath of skin (salt-solution) is higer conductive than dry surface of skin. Beside, if high current flows enough time on skin, it may carbonise and the resistance drops, so allows high current to flow. Effect force of electric shock on human body: It depends on current intensity and exposure time (Tasers generally use 50 - 1000 kV and 2.1 to 3.6 mA and some others use 18A, for about 10 sec.). Well, are there difference between AC and DC according to human body? Chest and head is relatively important section for the electric’s fatal effect. Heart period is typically 750ms. So, 750ms or more electric exposure can break heart period (fibrillation threshold of DC is approximately five times that for AC (Dalziel 1956)). Fibrillation meaning is the heart muscles are no longer working with coordination. Arc and Lightning is impulse, so different than pure AC or DC. AC holds and releases 50 times in sec. (50Hz), DC holds (almost pure DC). When hold the electric source with palm, arm muscle will contract (tetany) thus, gripping will become perfect for electrical transition. Electric is not only inside of the cable, when existing a electric in a cable, there will be around the cable as magnetic field (it depends on voltage) too. So, it not be necessary to contact the cable to complete the circuit. How fast the electric? With the wire (house wire), 10 amperes of current free electrons move about 0.02 cm per sec (drift velocity) [1], so it is very slow isn’t it? But electric conduction speed is very high, comparable with light speed. 

P.S.: Light can slow down the electron particles. 

P.S. : I wish there was no loss of life in the video which i have used. 

I hope it doesn't happen at all. 

Hakan N. Öztürk 

[1] http://hyperphysics.phy-astr.gsu.edu/hbase/electric/miccur.html

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Single Axle Bogie

Some railway wagons use direct connection between chassis and axle and some others use bogie systems. Direct connection systems generally use two axle (front 1, rear 1). On the other hand, there are many kind of bogie forms for locomotives and wagons. With 2, 3 or more axles (B, Bo, Co, (for locomotives), heavy load wagon etc.). Beside, some bogie systems use only one axle. There are advantages and disadvantages of bogies has 1, 2 or 3 axles. E.g.: When vertical disorders occur on track, middle axle can lose contact sometimes to rail surface. So, it can begin to skid more easily if the system is (Co). Because the vertical force has changed for each axle. Single axle bogies can have advantage especially for urban railway systems. Because, they might need to use narrow curve radius and low floor vehicles. Photo : Höje Taastrup, by Erik Hjelme.

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