Quote:
Originally Posted by VivaLFuego
The new cars have AC propulsion and on-board inverters to convert the DC power from the 3rd rail to AC power for the motors. Thus the new cars cannot be coupled with any of the old cars, but can run on the same power infrastructure (there will likely be some hiccups with the power and signal system that need to be determined and fixed during the prototype testing...the AC magnetic field may interfere with the signals in some locations, and it may be necessary to adjust the voltage on the 3rd rail).
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I'm an electrical engineer and this all seems very strange. From a black box perspective the cars should be externally identical, or at least thats how the requirements should have been written. Do the cars share power? Power converters should be able to handle that as well, and they should operate over a wide enough voltage range that the 3rd rail shouldn't need adjusting.
And I also can't imagine that the AC drives would have more EMI than the DC brush motors. AC drives are pretty quiet by comparison. It's surprising that signal equipment that works fine as a train goes by arcing on the 3rd rail would have interference from the AC motor or inverter.
I searched a bit for more information but didn't find anything usefull. Is there more info available, I'd love to read up on it.