Originally Posted by gunrunnerjohn:
BY "adjusting the throttle, I'm talking about the remote Throttle, either the DCS or CAB1/CAB2, depending on what you're running. We are talking command here, right?
I tried a Legacy and an MTH, and the input voltage to the TIU made no difference at slower speeds. I got up to around 50 scale MPH, and I actually did my measurements of distance traveled at 10 scale MPH and a like speed with the Legacy. As pointed out by Barry, maximum speed may suffer, depending on the actual track voltage, I did not test any maximum speeds.
I have also not tried the ERR Cruise Commander or Cruise Commander M engines, that would be another good test. Since the ERR cruise is based on motor back-EMF, perhaps that behaves a bit different with different voltages, though I've never observed a huge difference with different loads. I also didn't actually test the track voltage at various points with cruise performance in mind.
For MTH or Legacy engines, I don't see how a couple of volts track voltage would make any measurable difference in the locomotive speed at anything other than the maximum voltage limited speed. Another interesting test would be one of the TAS EOB equipped locomotives, they also use the tach strip on the motor and should not be seriously affected by voltage differences on the track.
This is a good experiment for ERR Cruise equipped ones, I'll have to give that a look. That's the type of cruise that I can see the track voltage may have an effect.
Thanks for the clarification. The procedure for starting TMCC or DCS engines is to set the voltage first at 18V or 19V on the Z4000, depending on which publication you read. After setting the start voltage at 19V, and using the Cab 1 to start the engine,
the start up and forward motion of the engine is normal. However, no matter how many times you turn the big red knob on the Cab 1, the engine won't go faster than about 15 mph. The engine is not geared for optimal speeds nor is the very high amperage demands of the can motor the optimal choice.
Now that the engine is rolling forward at 15 mph and you've turned the Cab 1 throttle clockwise as many times as you want, you have to physically reach down and return the Z4000 voltage back up to at least 18V, indicated and then the Cab 1 will move that engine lash-up out fast enough to have to slow down for 138 radius curves, as you would any other TMCC engine.
if you don't trim the voltage up from the draw down to 16V, and adjust it back to 18 or 19V, you're going to be running a very slow set of engines with the Cab 1. This is not a ERR problem, but a first generation ever release of a 3rd Rail diesel engine that isn't up to normal standards for TMCC. The first issue was a "guess" for gear ratio,
type of can motor, RPM optimal can motor speeds, and all the other things that should have been verified before release of the E-7's. Once one understands that the voltage has to be set higher, the E-7's will perform correctly.
When I first ran in to this problem I came to OGR Forum, asking others if they were having any performance speed issues with their new E-7's. The two significant replies I received were "What speed Problem?" After asking what they were using for power and how many feet of track was being supported and their TIU channel configuration, I realized that they had never fully understood the power requirements of a DCS set up "by the book".
What they had done was grossly over-powered the layout with double the Z4000 power and TIU power distribution requirements. Secondly, they had only bought only one E-7, as the RR they were modeling only used one E-7 for prototypical performance.
Once I understood how they were so satisfied with the speed performance, I bought a second Z4000 and split the layout into two separate Z4000 power distribution zones.
Now that I had far more Z4000 layout power required to operate a normal DCS and TMCC layout, I too, could get the E-7's up to 60 mph. However, before I added the second Z4000, my entire DCS and TMCC layout performed flawlessly using the star pattern of wiring that I've been using since 2004. The loop powering the E-7's, prior to installing a second Z4000, was my third expansion of the 2800 sq ft layout and I'd never had a problem before. Dave Hikel drew my first layout wiring schematics for me and using his diagrams, I wired the entire first section of the layout, placing the TIU's per his diagram and running the four color coded wires to each pickup point and to each TIU in and out channel. Dave came down from Seattle to my Sacramento location and installed a turn table for me and he then fine tuned the layout as needed. He also pointed out areas on the layout that needed tweaking to also support TMCC on the same tracks as the DCS.
So on this third layout expansion, it was not only by Barry's book, but also by Dave Hikel's recommendations. Dave recommended that when laying the cork roadbed, to place a 18 or 20 ga wire down the center of the cork, instead of having to lay the ground plane on the outside edge of the tracks. For the first time, I could run any TMCC engine flawlessly. I also had the correct number of track feet between pick ups and the center rail breaks as per the requirements. And last, but not least, I had the right amount of Z4000 power. Everything worked perfect for DCS and TMCC.
Except for running a 3rd Rail E-7 lash-up in TMCC. (Lessons learned.)
mokemike