auto-transformer system principles

[1greeny1]

hi,

i have recently been trying to make a little more sense of the auto-transformer system and how it helps boost the power in the circuit. from what ive gathered the feeder station transforms the national grids power down to 50kv and then this is cycled out between the contact/catenery +25kv and the auto transformer feeder wire at -25kv at 180 degrees from one another. at this point im struggling to understand how the atf supplies extra power to the system as from what i gather it never actually directly feeds the catenery? im not sure if its to relevant for these forums or whether i need to be a physics one to get a better understanding of ac circuits. any help would be appreciated thanks.

 

[GRALISTAIR]

Try this piece of brilliance from Garry Keenor

Garry Keenor (He/Him) @25kV

Join me *live* (eek!) now for a #STEM introduction to OLE, what it is how it works, why it is important#RailHumanLibrary #railwaysexplained #rail101 @RailHumanLib @NTHRailLeaders @GUTS_STEM @intorail @youngrailpro @NSARLtd @lydiafairman

www.pscp.tv

 

[Elecman]

Look up Garry Keenor’s excellent work here http://www.ocs4rail.com/ for more info

 

[plugwash]

(my termininology may be off, i'm an electronics guy not a railway guy)

Along the lenghth of the railway, autotransformers are connected to the autotransformer feeder, the regular feeder and ground. The autotransformer essentially transfers power between the two feeders to try and keep their voltages equal.

When a train draws power that causes volt drop in the main feeder, which causes power to flow through the autotransformers from the autotransformer feeder to the regulat feeder. The end result is that roughly half the trains power comes from the main feeder and roughly half from the autotransformer feeder and currents in the ground conductor are signigicantly reduced.

 

[1greeny1]

Thanks for the quick responses I'm slowly reading it.
So would that mean both the auto feeder wire and contact (regular feeder) are fed at the same point I.e switch but never actually directly connect together. The contact Is fed from the feeder wire but through the feeder station when the feeder station requires more ?

 

[GRALISTAIR]

The Wikipedia article on it is not too bad - unfortunately only a small section on railway application

Here https://en.wikipedia.org/wiki/Autotransformer