Question on Caternary

[rdamon]

Saw this in operation in Rio ..

http://www.alstom.com/products-services/product-catalogue/rail-systems/Infrastructures/products/aps-ground-level-power-supply/

[RME]

rdamon

Saw this in operation in Rio ..

http://www.alstom.com/products-services/product-catalogue/rail-systems/Infrastructures/products/aps-ground-level-power-supply/

Little difference in principle between this and the pre-WWI GE systems that powered only the contacts under a car requesting power.  In fact, if I recall correctly, at least one of the GE designs used technically-RF induction and not just energized DC electromagnets to 'pull' the power relays on, making it for all intents and purposes a 'wireless' (e.g. radio) system.

Naturally if you code the system like a garage-door opener, there is much less chance of accidental energization than if you were to use simple proximity (like the sensing in some of the inductive-charging arrangements) or simple RF handshaking arrangements.  I have not looked carefully at the APS patent specs, but I wouldn't be surprised to find that security and prevention of malicious tampering were major features of the present design. 

It doesn't hurt that solid-state relay design gives a much more robust and reliable product for switching traction voltage than the technology GE had to use 'back in the day'...

 

[Paul_D_North_Jr]

tree68

RME

Of course, if you stepped wrong and shorted the DC across your lower body,

If you stepped wrong and shorted 600 VDC at a gazillion amps across your body, I suspect a malfunction in your pacemaker or insulin pump would be the least of your troubles.

See what happened to actor Robert Shaw (forget the name of his character) in the last scene of the movie "The Taking of Pelham 123". 

[Electroliner 1935]

As some have called those who got fried, A Crispy Critter. 

[nfotis]

ORNHOO

This year's snowpocalypse seems to be bringing the usual problems to electric traction systems; increased tension due to cold weather, ice buildup on conductors, etc. In good weather conductors on pantographs are subject to wear and need frequent replacement. Has anyone built a system where electricity is "harvested" from the caternary by electromagnetic induction without direct physical contact?

 

The 'constant tension' catenary systems which use counterweights are the correct solution to the first problem.

The exchange of graphite collectors on pantographs is not a major cost/problem, as far as I know. Contactless energy transfer is quite limited for mainline traffic at the moment, and it is practical only on tram/light rail applications (with covered inductive conduits etc., in a very short distance from the collectors)

N.F.