• FB-3 variant queries

  • Discussion of General Electric locomotive technology. Current official information can be found here: www.getransportation.com.
Discussion of General Electric locomotive technology. Current official information can be found here: www.getransportation.com.

Moderators: AMTK84, MEC407

  by Pneudyne
I suppose you could say that GE had an "Edisonian" moment when it decided to stay with DC-DC transmissions when others in the industry were pursuing AC-DC.

That might be a bit harsh, though. Recall that in the PRR E2b vs. E3b/E2c saga, GE maintained that the better solution was a four-motor locomotive unit (following established diesel-electric practice) with improved conventional single-phase motors, basis its superior high-speed power. Westinghouse’ starting position was a six-motor locomotive with smaller, resistance lead single-phase motors. GE thought that resistance-lead was definitely not a good idea. Westinghouse then switched to ignitron rectifiers with standard diesel-electric type DC traction motors, which provided much better low-speed performance, although it was inferior at high-speeds. That combination was more attractive to PRR. So GE was on the AC side of the argument in that case. But even though it was initially lukewarm to the idea of rectifiers, it could turn on a dime when needed, and so was soon building six-motor ignitron rectifier locomotives with standard diesel-electric DC traction motors. In fact it had championed that form of motor for motor-generator locomotives in the immediate post-WWII period, but that turned out to be a very limited market. It did note that the E2b” could be built in both motor-generator and ”straight” DC versions, but as far as I know, no details of these variants have ever appeared.

It is also interesting that Alco sometimes used GE developments ahead of their use by GE itself. Perhaps GE wanted to be seen to be treating Alco fairly, and so help itself to stay well away from any antitrust concerns. Alco, I think started using Type E excitation before GE offered it in its own models (the GTEL8500 excepted).

GE also evidently held quite strongly to the notion that the domestic diesel-electric locomotive was ideally a four-motor unit – perhaps a carryover from the E2b thinking – hence the U25B was equipped with relatively fine control of starting tractive effort (following GTEL and electric locomotive practice) and comprehensive wheelslip control, but initially at least not offered in a six-motor variant. You could say that the FB3 truck and the U28C signalled its recognition that the six-motor unit was important per se, and not just a sidebar. Perhaps the Seaboard U36B- plus-MATE was the last stand of the four-motor brigade? It was different for the export market though, as C-C was the majority choice for the line-service Universals. In fact, in the later 1950s, GE penned an article that opined that A1A-A1A was a bad idea, and that C-C was the way to go wherever (in the export market) six axles were required. (At the time, EMD was building quite a few A1A-A1A export models, and Alco offered, but never built this wheel arrangement on its standard export models.)