Slow speed for Walthers H10-44

[trnj]

I have a Walthers H10-44 with DCC and am quite pleased with it overall.  The only "fly in the ointment" is its low-speed performance when it starts.  I cannot get it lower than 2 SMPH, making it lurch when it starts.  The mechanism is not binding and I have "tweaked" the appropriate CV's. (e.g., CV2, CV3).  My RampMeter shows the engine is running very well, with small current draw (.002 amp).  I think the effect when the engine starts stands out more in my mind since I have four engines with LokSound decoders and their low speed start-up is amazing (two 44 tonners, a Stewart VO-1000, and an old Atlas S-2).  My only other QSI-equipped engine (a BLI SW-7) has the same performance issue but not as obvious.

Any suggestions would be appreciated.  I do have a Quantum CV manager, so I can create a custom speed table if necessary.  I am currently using the spped table, CV25 = 3.

John C.

 

[rrinker]

 Is it new enough to have the newer QSI chip with the BEMF enabled? If so, turn it on. It will help immensely with the low speed running. 2smph isn't bad at all though. It's not a speed table issue, if it starts at 2smph on step 1. It might not go any slower than that.

                                            --Randy

[Hamltnblue]

There are also other settings which include the PID values for BEMF on QSI.  Other manufacturers have similar settings to do the job.  Check page 271 of this guide for qsi

http://www.qsisolutions.com/pdf/quantumdccrefmanual_4_6_0.pdf

[fisker76]

Set CV 25 to linear speed table

Set CV 2 to the lowest value where the engine will still move

Set your BEMF to the lowest value where the engine will still move

Now set the "P" value for Very Slow Speed in PID Parameters; usually to a lower value than what is already programmed.

This should get you a nice smooth slow start.

You can now go back to the CV 2 value and increase this or not;  Setting CV 2 & 5 to higher and lower values essentially creates a custom speed table.  For example CV 2=25 & CV25=125.  I use this to limit maxium speeds on my layout to a very realistic 25-30 scale mph

You can also increase BEMF, however, I've found nearly all locomotives operate best with a value ranging from 2-4; Trix Locomotives and some Bachmann Spectrum steamers being the exceptions as they have some unique motor/power transmissions. 

You can also go to http://groups.yahoo.com/group/QSIndustries/ for indepth discussions and helpful advice concerning QSI products.

Erik Fiske