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Re: Someone please explain shifting gears in a diesel
Author: SP5103
Date: 12-16-2010 - 12:58
Thanks for the links - the actual page of interest is Transitions Chart for FM-TM
From this info:
3S-2P about 0-14 mph
3S-2P shunt 1 about 14-22 mph
2S-3P about 22-26 mph
2S-3P shunt 1 about 26-40 mph
2S-3P shunt 2 about 40-65 mph
(Assuming the SP TM's had the same gearing)
3S-2P means that there are 2 parallel strings of 3 traction motors wired in series - each traction motor getting 1/3 the voltage and 1/2 the current.
2S-3P means that there are 3 parallel strings of 2 motors wired in series - each traction motor getting 1/2 the voltage and 1/3 the current.
The change in traction motor connections ("shifting" noticeable from trackside) would have occured at about 22 mph, a little lower speed for backward transisiton.
These FM's had Westinghouse electrical equipment that have different characteristics than (Alco)/GE or EMD that I am more familiar with. The only thing "standard" in the railroad industry are the numerous exceptions to the "standard".
From this info:
3S-2P about 0-14 mph
3S-2P shunt 1 about 14-22 mph
2S-3P about 22-26 mph
2S-3P shunt 1 about 26-40 mph
2S-3P shunt 2 about 40-65 mph
(Assuming the SP TM's had the same gearing)
3S-2P means that there are 2 parallel strings of 3 traction motors wired in series - each traction motor getting 1/3 the voltage and 1/2 the current.
2S-3P means that there are 3 parallel strings of 2 motors wired in series - each traction motor getting 1/2 the voltage and 1/3 the current.
The change in traction motor connections ("shifting" noticeable from trackside) would have occured at about 22 mph, a little lower speed for backward transisiton.
These FM's had Westinghouse electrical equipment that have different characteristics than (Alco)/GE or EMD that I am more familiar with. The only thing "standard" in the railroad industry are the numerous exceptions to the "standard".
