Railroad Forums 

  • Alternators... asking again

  • 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: MEC407, AMTK84

 #27183  by timz
 
"...at higher speeds so that the traction motors "think" they have been re-wired in parallel even though they are still physically connected in series."

I'm guessing traction motors are always in parallel on road locomotives built in the last 20 years or so.
 #27364  by Allen Hazen
 
EDM5970--
Thanks! (Actually, it was publicized at the time that the HEP generator was in the "steam generator compartment": where the steam generator is on a Santa Fe U28CG or an NdeM U36CG.) ... As for the Central Air intake... how many times has GE switched the location of the central air intake?
U25B: near radiator
"U30/1967" generation (starting with late U28: in front of generator
U34CH: back, probably, to the radiator compartment
C30-7: front, as on U-series
B30-7/B23-7: rear
B30-7A1: front again
Dash-8/Dash-9: front
---
Timz:
My mistake. Should have been "the traction motors at low speeds think they are in series even though they are physically in parallel"?
Sorry.

 #27596  by timz
 
Dutch R was wondering about alternator transition. Maybe it's a semantic distinction-- the two sets of stator windings are connected to two sets of rectifier diodes (or whatever), and I assume the DC output is what gets reconnected from parallel to series as the loco accelerates. Do all six-axle engines do this now?

I wonder if lineside fans can hear the engine making genertator/alternator transition. It must unload momentarily?

 #27607  by DutchRailnut
 
Locomotives have had no transition anymore for last few years, with DC tractionmotor being able to handle higher currents they have been in permanent parralel for years.

 #27770  by timz
 
Yes, the motors have been permanent parallel for years-- but likely not the alternator/generator (on C-Cs, anyway). Dunno about AC-motor diesels, but the SD60 used/uses two sets of alternator stator windings, and I bet the SD70 does too.