mechanics corner 9809
When GE Contracted to build Engines for Amtrak in the Early 90's, it was decided to go another route, rather than have a separate Delco to create 480 Volt power.
GE created a 2 in 1 main alternator that did away with any extra alternator and drive systems. They still have a Standby mode for when the Engines are at a Station for a period of time, but its all contained in 1 large alternator.
This creates a quieter running Engine all the way around since GE's are a four Stroke Engine and makes less noise, (see the first Mechanics Corner for a article on RPM and noise).
A big draw back with both the EMD and GE designs are that they both use Main Engine, or Prime Mover Power, and thus give up some of their Horsepower, about 500, generally speaking. That's why occasionally when a power consist is short on Horsepower, they will shut down the HEP(480 Volt) power when climbing a grade, or other circumstance when they need more power.
Some GE's on the East Coast can operate off of their Prime Mover or pick up ground power,(third Rail) permitting them to run in Electric territory. Also I believe EMD has an older Cab unit that runs either in Electric territory or on its own Prime mover.
next time: Other 480 systems.