Voltage drop at 12V - is there a table?

[bernardgreen]

The current created by the "booster" transformers is not part of the circuit returning the motor current back to the sub station. That return circuit for the traction power is a very diffused ( many parallel paths ) route through the earth and other conductors.

The current created by the booster ( miss named ) tranformers in the cable is equal to and flows in the opposite direction to the current in the over head wire supplying the trains. The cable is run as close as possible to that over head wire ( but still several feet away ) so that the magnetic fields created by the two currents cancel each other out. Before "boosters" and the "counter current" wire were used all cables along side or close to the track had very large voltages induced in them when an electric train went past. This created serious problems for signalling and communication designers and engineers.

 

[JohnW2]

The current created by the "booster" transformers is not part of the circuit returning the motor current back to the sub station. That return circuit for the traction power is a very diffused ( many parallel paths ) route through the earth and other conductors.

I don't think this is really relevant to what I was discussing but, given the connections between transformer secondaries and the rail, it's difficult to see how they can fail to be part of the 'diffused' main return path (i,e, one of the many parallel paths) - albeit a very small part of that path due to the impedance of the transformers' secondaries (compared with othe paths).

The current created by the booster ( miss named ) tranformers in the cable is equal to and flows in the opposite direction to the current in the over head wire supplying the trains. The cable is run as close as possible to that over head wire ( but still several feet away ) so that the magnetic fields created by the two currents cancel each other out.

I fully undertstand what the system is designed to achieve, and presumably does achieve. However, as I said, what was/is confusing me is that, for all but the 'last' transformer, the two sides of the secondary are joined together via two wires and a length of rail.

Kind Regards, John.