One of the operators of the train group I belong to has a switcher (S1) that has too much momentum; the engine has a sound decoder. He has asked me to reprogram the momentum CV to eliminate the momentum. I said i would try; upon reading up on this topic it appears that there is no "momentum" CV, it's more of a combination of the CV 's that affect speed, etc. My plan is to reprogram CV's 2,3,4,5 & 6 to zero. As it has a sound decoder, I will check his decoder sheet for the loco first to see if they have all of those CVs. Any thoughts on my 'plan'? Suggestions are always welcome!
CV3 is aceleration momentum and CV4 is deceleration momentum. Depending on the decoder, these can range from 0-255, some brands limit it to 0-32. Without an independent brake, values of 100 and over are generally not controllable in a model situation. The detailed manuals for various decoder brands usually specify the formula used for momentum values.
CV3 is for acelerating. The bigger CV3, the longer it takes the loco to get to the set speed on the throttle - you can open it wide and the loco could take 10 seconds or more to actually get to top speed. CV4 is the opposite. The bigger CV4, the longer it takes the loco to slow down and stop, even if you turn the throttle to stop.
I would start with just CV3 and 4, if you mess with CV2 you will affect the starting characteristics of the loco, CV5 will affect the top speed at full throttle, and CV6 the speed at mid throttle.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy,
Thanks. That makes sense based on my little understanding of the article in July Model Railroader. As it is Ops Programming, it should be easy to change the settings and then see the effect. I will also check the decoder manual if he has a copy in his file, which he thinks that he does.
Mr. Mick