Pantograph and Trains
Pantograph is a very interesting device that you may find on the roof of electric trains, trams or electric buses.
And the primary purpose that it serves is to collect power from the overhead power line to run the motors of the train without losing contact at higher speeds.
The train takes the current
from the over head line and the current flows to the tracks
which are earthed at regular intervals via the axle brush on the train.
This completes the circuit.
The overhead lines are kept in tension and dropper wires are placed at multiple locations to ensure that the contact wire does not bend under its own weight.
And since any two objects that rub against each other, constant frictional contact would wear them out, the Pantograph and the contact wires have a sliding contact.
This results in less wear for both the Pantograph and the contact wires resulting in lesser maintenance.
Graphite conducts electricity extremely well while also working great as a lubricant due to it’s self-lubricating properties and therefore most contact strips on the Pantographs are made up of Graphite.
It’s a very simple apparatus with an extremely pivotal role and that’s what makes the Pantograph special. Have a great day!
** Third Rail
*** Arcing is a serious problem when we are dealing with any high voltage lines. in bullet trains which operate under higher voltages, the Pantographs are always forced to be in contact with the contact wires through a dynamic lever-spring mechanism. (Source)