RailPro User Group
RailPro => RailPro Specific Help & Discussion => Topic started by: nhhotrain on February 20, 2016, 03:43:02 PM
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Prior having the RailPro products, I took out a motor out of the FB-1 so I can run FA-1 and FB-1 together without losing couplers if the FB-1 ran too fast or slow. The FA-1 locomotive didn't run well. I put them away for a long time until last year when I started purchasing the RailPro products. I restored the motor back on the FB-1 and I used Digitrax DHWH harnesses on both FA-1 and FB-1. They run together awesome and the FA-1 locomotive even runs much better!
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That's good to hear. One of the features of RP is automatic speed matching after setting the maximum current of each locomotive. This works with as many engines as you would like to consist.
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Technically it's load sharing, not speed matching. Without the module knowing motor rpm, gear ratio and wheel diameter there's no way for it to automatically match speed (and you can see this when running an MU as light engines). Load sharing mimics how the prototype operates better than speed matching. It would be interesting to learn the science behind Rings load sharing.
- Tim
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Another neat thing is that you can link a number of locomotives without actually coupling them together. These locos can be placed anywhere in the train and they will run perfectly.
Mel
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I have no internal knowledge of Ring's MU software but I have a suspicion of how it might work - motor current draw. By comparing the current draw of each engine in the lash-up and then adjusting for the combination that yields the lowest non-fluctuating current of each loco (at given speed setting), the motors are then providing the same pulling effort. An over-pushing loco will see amperage rise while the pushed loco will see amperage drop. I believe the controller uses info from each module to make the necessary real-time adjustments to prevent rise/fall of amperage. This approach makes the mechanics and efficiency of the locos irrelevant which explains why RailPro MUing works so well with different manufacturer/model locos. Just guessing. Doesn't matter. Regardless of the means, RailPro MUing works great. Really puts DCC to shame.
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Tim doesn't give out much proprietary information about their products. Alan's explanation makes sense. Current draw is expressed as a percentage of maximum current, as opposed to milliamps, for each engine. The controller must be using changes in that percentage to make minute throttle adjustments as necessary. That might account for 1000 speed steps.