Good day, all - I have posted my notes after reviewing the new Revolution Base Receiver - see:
http://www.trainelectronics.com/ART5700TrainEngineerRevolution/TrackSideRevolution/NewBaseUnit.htm
Please let me know if you have any questions or if there is anything else that you would like to know.
Thanks!
dave
Dave, did you measure the current capacity? (short and long term?)
I see that properly heat sinked the output FETS can do 107 watts.
At 24 volts, that is 4.45 amps, right?
And that assumes 25 degrees C (77 Fahrenheit) which could only be achieved on a normal day with a cooling device, not just a small fan.
Just wondering what the real output capabilities are, the heat sink is large, but the FETs are like other decoders, and the foam is not the best thermally, it’s thick and not metal filled.
Regards, Greg
I have not had time to get that test done, Greg - my priority was to get the majority of it posted.
Power testing (similar to what I did with the original unit) is on my TODO list!
Right now I have to undo the damage done to the railroad by a very nasty winter and a rapidly growing Golden Retriever puppy who loves to dig & chew track and trestles!
dave
Greg - I finally had time to set up a power test on the receiver this morning. I ran a total of 16 motors from the receiver and it ran very well while supplying over 7.5 amps. I would have tried for more but I ran out of stuff to put on the track!
For details and a video see:
https://www.youtube.com/watch?v=EA9fXzfIAf4&feature=youtu.be
dave
Thanks Dave. I’ve put together some 8 to 10 amp loads, but they are simple resistors, so not really motor loads.
7.5 amps without fan cooling is very good.
Regards, Greg
Greg- I considered using a resistive load (12 volt automotive bulbs in series/parallel) but feel that an inductive load more closely matches what we use on our railroads.
As the video shows 7.5 amps spins a bundle of motors!
dave
Yes, the resistive load is too “nice”… need that nasty 0 ohm “stall” impedance to really test the fortitude of the unit.
If I remember right, these are 50 or 60 amp FETs, so I would think that the first problem encountered would be a long term overload where the heat sink could not shed enough heat, rather than the inductive “kick” wiping out a junction.
What do you think?
Greg
Greg - heat doesn’t seem to be an issue, at least with the setup I used - ambient temperature was about 75 and I did not use a fan ---- Even a small external fan would dramatically change the issues with heat — not sure if it is available yet but the folks at Crest mention a fan add-on for the receiver - if I were using this at 6 or more amps, especially in a hot environment, I would add a fan.
dave
You know if you put one in a diesel, you could make the fans on top really work 
Dave, I guess I am not making my sentences very clear…
I said the first problem that WOULD be encountered with a long term OVERLOAD…
Not what you tested… that was and is clear to me.
Again, I would like to know the limits of the system, and my GUESS is that the heat sink used would not allow the FETs to run at their maximum current, 50 or 60 amps… just not enough thermal dissipation…
I tried to make this clear this time… let me know if I did any better please… I’m really trying to communicate and apparently doing a poor job…
Greg
Greg Elmassian said:
Dave, I guess I am not making my sentences very clear…
I said the first problem that WOULD be encountered with a long term OVERLOAD…
Not what you tested… that was and is clear to me.
Again, I would like to know the limits of the system, and my GUESS is that the heat sink used would not allow the FETs to run at their maximum current, 50 or 60 amps… just not enough thermal dissipation…
I tried to make this clear this time… let me know if I did any better please… I’m really trying to communicate and apparently doing a poor job…
Greg
Right you are about my not understanding, Greg - I gather that you would like to run the unit at its limits to see how it holds up. Perhaps a 15 amp inductive load for an hour or two?
If so that is something that I am not set up to do right now… perhaps you or someone else could tackle the test.
dave
Yeah, just curiosity at what the max continuous rating is w/o and with a fan at some typical ambient. Just curious.
I don’t have any revolution equipment any more, I returned the evaluation hardware sent to me.
Clearly, at least in my opinion, this receiver has enough capability to run virtually any multi-unit consist someone would come up with, but maybe not with lighted passenger cars.
(I have a 10 amp train, 3 Aristo E8’s and 10 USAT streamliners)
I know a number of people running track power with “10 amp trains”, so while clearly in the minority, it would be nice to know the actual limits.
Regards, Greg
I would be interested to see what happens in those high power setups but it is not practical for me to cobble together something with the trains I have on hand. I rarely run anything with more than one steam engine.
dave
No problem Dave, was not trying to coerce you!
Just explaining why the knowledge would be useful.
One day I’ll pick a unit up and give it a whirl… I can easily run up to 20 amps in trains.
Greg
Dave - Load testing here at G-Scale Graphics has always been a priority. I want real world specifications based on testing, not speculation. I use an electronic load to push my circuits to the limits with precise control. Just dial it up to whatever you want. Very nice!
Of course if you don’t have an electronic load, you use whatever you have. That was quite the concoction of locos flailing about, but it did the job ! 
Thanks for the review.
Hi, Del - does your electronic load represent an inductive or resistive load? As discussed above my goal was to provide something similar to what a motor (or motors) would provide.
thanks!
dave
Great review Dave. As an old school Train Engineer guy, I appreciate the information. Some day if I live long enough, I may have to change over to a more updated TE. So I appreciate the information on this unit. I had to add fans to my old TE’s almost from the beginning. I con’t seem to understand where they would go on these new units.
Thanks
David Bodnar said:
Hi, Del - does your electronic load represent an inductive or resistive load? As discussed above my goal was to provide something similar to what a motor (or motors) would provide.
thanks!
dave
It is resistive. Nothing wrong with your test at all. I was just pointing out the flexibility an electronic load provides in being able to have high resolution on the load you apply, all in a compact package sitting your your bench. Of course I do plenty of testing with motor loads, and large scale locos as well.
It would be good to have an inductive load, I only have a 8 amp resistive load. It might be a cool idea to have some sort of rig with a number of USAT motors and some way to physically load them, like a dynamometer.
I also don’t have a handle on how the inductive load presents itself different than resistive, except of course the obvious, that motors present a very low impedance at near zero rpm.
In this case, the fact that the motor is inductive is more of an interesting fact, it’s the radically varying and very low impedance that seems to be the issue.
Regards, Greg
Gents - the other thing that the motors provide is electrical noise that can drive electrical gizmos crazy. Resistive loads are quiet.
I have had situations where circuits that I have designed needed rework due to sensitivity to motors that are “dirty”.
dave