# Revo and Multi Diesels



## Randy Stone (Jan 2, 2008)

Will the Revo transmitter operate 4 Revo Receivers at the same time? I have 4 USAT F3s which I would like to run in tandem. I'm sure they all won't run off the same Revo receiver, but will one transmitter work the 4 receivers? My transmitter is not the one with sound. Can I use the receivers with sound?


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## Greg Elmassian (Jan 3, 2008)

I think you are asking about consisting... yes you can do that.

I forget the limit of locos, but you assign multiple locos to a cab number and then that cab runs all the locos...

Greg


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## Randy Stone (Jan 2, 2008)

Thanks Greg


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## Treeman (Jan 6, 2008)

That will include the newer units with sound.


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## East Broad Top (Dec 29, 2007)

Easy to do. You'll set a cab up as an "MU" cab, then under that, select which specific receiver addresses you want that MU cab to control. You can group up to 6 receivers. You can scroll through which of the units is the "lead" unit by using the "*" key. The Function keys will only affect the lead unit, so if you've got sound installed, only the lead unit's horn, whistle, bell, etc. will trigger. The lights, however, will be on for all the units. For something like an A-B-B-A lashup, that won't make much difference since the B units don't have lights, and presumably the rear A unit would be running backwards.

Note also that if the rear A unit is to be run by itself when not in a consist, you'll have to reverse the motor polarity when you put it in the consist so it runs the proper direction with respect to the rest of the consist. 

Later,

K


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## Stan Cedarleaf (Jan 2, 2008)

Randy... I've run 4 diesel units (FABBA) using one regular onboard REVOLUTION in a battery car and it worked right well until the weather warmed up to 90 degrees. Then the receiver overheated... 

Bare Chassis.... 










Full Running.... 










I switched to a 15 amp Trackside REVOLUTION and it worked great with the FABBA set.... I would think the regular REVOLUTION receiver would overload with just 2 F3's


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## Greg Elmassian (Jan 3, 2008)

Yes but the difference between the old style Aristo FA motors and the USAT motors is huge.

The USAT motors have a very high stall current, i.e. they can draw a lot of current when starting or under load.

Greg


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## harvey (Dec 30, 2008)

Hi Randy,
This is a good question and looks as though Stan has answered it for you. I've never thought of running with a single receiver, but I've often run three loco's in MU mode with forty to fifty cars in the drag. Let us know if you try this and how it works for you.
Cheers.


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## Randy Stone (Jan 2, 2008)

I have three Aristo F units I'll try Stan's idea, but for the USATs, I'll most likely will go with separate receivers unless I find one I know will handle 4 diesels.


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## Greg Elmassian (Jan 3, 2008)

Good thinking Randy... 

For the people who seemed to ignore my comment that the USAT motors are WAY different than the Aristo, read this page from George Schreyer

http://girr.org/girr/tips/tips4/tractive_effort_tests.html

Look at the stall current numbers.

Greg


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## Randy Stone (Jan 2, 2008)

So, the question: Is there a receiver out there that can handle 2, 3 maybe 4 or 5 locomotives all at the same time? Being the receiver could be located in a passenger or freight car, size wouldn't have to be as much of a limiting factor. At $105.00 for each Crest (Aristo Craft) Revo receiver, I could be looking at $402.00 just in receivers. Surely somewhere out there in the 21st century is a low cost receiver that would do the job.


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## Greg Elmassian (Jan 3, 2008)

2, 3, 4, 5 locos at the same time?

If they are Aristo FA units, yes, they do indeed "sip power", and you should use the Revo "super receiver" as listed on their site.

If they are USAT units, no, not with any load attached to them.

I would make this suggestion: run 2 locos from the same receiver, and permanently couple them. Put a speaker in each loco. 

This way, if you blow the horn, it's just from the first 2 units, not as bad sounding as having it from all the locos. 

Also, the Revo should handle 2 USAT locos, so you can "standardize" your installations between Aristo and USAT.

Greg


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## Stan Cedarleaf (Jan 2, 2008)

Hi Greg... As you've stated about the USA/Aristo motor difference, (just my experiences) I found that when using the standard REVOLUTION receivers wired to the USA locomotives through the USA boards, there definitely was a much greater current draw and much shorter battery run time compared when wiring the same way to the Aristo FA boards.

I tried a different "method" with the USA installations and bypassed the USA boards by wiring the output from the standard REVOLUTION receiver directly to the input of the USA motors. Doing that, I found that the battery run time and current draw was quite similar to the Aristo motors. I then "gutted" the USA boards and installed LED's for the lighting and found that, while it was a bit of extra work, the run times were very similar and I was quite pleased with the results. The USA engines I used for these conversions were the GP 7/9, GP 38's, NW2 and motor blocks from the 44 tonner's. 

All that to say, now that the PCSRR is a fallen flag, all that has gone away and I've switched over to some very limited O gauge running. The experience that I've learned here on MLS and "playing with" large scale trains has been invaluable. It's just been amazing for all the knowledge and sharing.


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## Jim Agnew (Jan 2, 2008)

I swap out the traction tired drivers for non-traction tired ones on the USAT engines and thereby avoid the high stall current problem.


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## Stan Cedarleaf (Jan 2, 2008)

Yes, Jim... I found that to be a big help as well.... Especially when running under battery power and have the engine derail or "bog down".


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## Greg Elmassian (Jan 3, 2008)

the USAT boards DO have a number of regulators on them, and they are the old style linear regulators, i.e. not efficient. It's hard to believe that they would use a lot of energy compared to the motors, but I guess they might.

The motors are wired directly to the track, through the motor switch, so your changes did not affect the power to the motors or their efficiency, but just losses elsewhere.

Since you also mention going to LEDs, not only did you eliminate the regulators, but perhaps an amp or so of current to lighting.

All that notwithstanding, my measurements on current draw parallel that of our esteemed rocket scientist, Mr. Schreyer (yes, he IS a rocket scientist)

Greg


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## Stan Cedarleaf (Jan 2, 2008)

"All that notwithstanding, my measurements on current draw parallel that of our esteemed rocket scientist, Mr. Schreyer (yes, he IS a rocket scientist)"

He sure is, Greg... What a great information source for the railroad bunch... 

Yes, by going the LED route, all the boards were removed and a lot less current was used...

Thanks so much....


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## Greg Elmassian (Jan 3, 2008)

No Stan, thank you for presenting the info that the LED conversion and elimination of all those goofy regulators screwed to the weights made a difference.

Nothing more helpful than real experience and results, sometimes we spend days on theory and forget the practical side of real experience.

I think I found 3 or 4 DIFFERENT lighting supply voltages in a USAT F unit... just crazy!

From my site on my F3 main page:

* Now to the cab lights and headlights.*

The 3 pin connector uses the black wire for common, the red wire powers the cab and number boards, these are GOW, and I reversed the polarity to them, they still lit. (means no regulators or diodes on the circuit board in the nose to these). These were supplied a regulated 3 volts from the original circuit board. They drew 135 ma at 3 vdc. This would require a 126 ohm resistor at 2.3 watts.

The front headlights are GOW also, and were supplied a regulated 3.57 volts (in the forward direction only) from the original circuit board. At this voltage, the 2 bulbs drew exactly 100 ma. That would make a 164 ohm resistor at about 1.6 watts.

There's also a rear headlight, off to one side of the rear door. I checked this later, and it drew 39ma at 3 volts.


Greg


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## Stan Cedarleaf (Jan 2, 2008)

Greg Elmassian said:


> {snip}
> I think I found 3 or 4 DIFFERENT lighting supply voltages in a USAT F unit... just crazy!
> 
> From my site on my F3 main page:
> ...


That's very interesting, Greg. Are the GOW bulbs12 volt or are they regulated at 3 volts??? 

This is what I did for the lighting after gutting the boards. 

Since the input voltage to the REVOLUTION receiver was 14.8 volts using Li-ion batteries, I used 1/4 watt 1k resistors on each LED which were scavenged out of a string of warm white LED''s from a 50 lamp Christmas tree lights purchased at Walgreens. 4001 diodes were used to control directional lighting. That probably wasn't the "technically" (or politically)  correct way of doing it, but the lighting worked very nicely with the REVOLUTION PWC output and I ran them that way until I sold the railroad. Sigh.. 

I did save a few custom designed and kit bashed G gauge pieces and they're powered and lighted the same way.


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## Greg Elmassian (Jan 3, 2008)

Actually, GOW bulbs come in all voltages, and no incandescent builb is self regulating, although they handle overvoltage much better than LEDs. (this is because the hotter they get, the more their resistance goes up)

All these different goofy voltages were regulated. The measurements I made were to determine what dropping resistors to use on DCC if I was to retain them, which I did in several installations.

There's no political correctness to LED installations ha ha, just trying to set the right current. Today's LEDs are much more tolerant of a wider current range than 10 years ago, but I always encourage people to calculate the LED current.

You want the resistor to provide about 20 ma of current. With Ohms law, if you have the voltage and current you calculate the resistance.

take your 14.8 supply voltage, and subtract the 3.6 volts of the white led (guessing white) and you get 11.2 volts... so if you use V = IR, or convert it to R =V/I you get it... R = 11.2 volts divided by 0.02 amps and you get 560 ohms for 20 ma... in your case you are running closer to 10 milliamps. If the brightness is OK then fine, no problem, if not you can reduce the resistance to get more current.

in actuality, I did not account for the 0.7 volts lost in the diode also.. but that's a small impact.

Also, since you are running only about 10 milliamps, the 1/4 watt resistors will be fine P = I (squared) R, or .01 * .01 * 1000 ... or .1 amp... 

If you did go to 560 ohms, you would be very close to 1/4 watt, and the rule of thumb is to never run resistors over 1/2 their rated wattage.

(I know some people believe differently... but they are wrong, a resistor running at full capacity will melt plastic)

Greg


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## Stan Cedarleaf (Jan 2, 2008)

Thanks so much for the "formulas" and information, Greg... 

I've found that the 1k resistors using the 14.8 batteries has given very acceptable "brightness" to the LED's. I realize that what I've done hasn't been to "optimum" specs but it's worked OK for the application. 

Again, thank so much..


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## Greg Elmassian (Jan 3, 2008)

Hey, if it is bright enough, you are saving power, lowering heat, and lengthening life.

Nothing wrong there... 

Greg


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