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Re: What became of SP 3201 and 3207
Author: OPRRMS
Date: 02-24-2012 - 20:25
Hutch 7.62 Wrote:
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> So a Locomotive converts to from a parallel
> electric system to Series when run backward?
No. "Transition" is a sequence of electrical steps similar to how an automatic transmission shifts gears in your car. As the speed increases, Forward Transition occurs. As the speed decreases, Backward Transition occurs. By the mid-1970's, the SDP's were notorious for having Backward Transition problems, which the Mechanical Department claimed were related to their use in commute service. As the speed decreased and Backward Transition should've automatically occurred, often the units would just stop loading altogether. The only way to *legally* get it to load again was to momentarily slap the throttle handle into IDLE, then quickly bring it back out to whatever position it had been in - you had to do this real quickly to prevent a serious slack run-in and potential break-in-two when the slack ran back out.
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> So a Locomotive converts to from a parallel
> electric system to Series when run backward?
No. "Transition" is a sequence of electrical steps similar to how an automatic transmission shifts gears in your car. As the speed increases, Forward Transition occurs. As the speed decreases, Backward Transition occurs. By the mid-1970's, the SDP's were notorious for having Backward Transition problems, which the Mechanical Department claimed were related to their use in commute service. As the speed decreased and Backward Transition should've automatically occurred, often the units would just stop loading altogether. The only way to *legally* get it to load again was to momentarily slap the throttle handle into IDLE, then quickly bring it back out to whatever position it had been in - you had to do this real quickly to prevent a serious slack run-in and potential break-in-two when the slack ran back out.
