Keep Alive installation w/ Railpro

[Alan]

What about using this up converted higher voltage with the AR's and other Ring Engineering components?

The only potential issue with a DC up converter, or any buck converter for that matter, is ripple current resulting from the internal inductor design. Here is an article explaining: https://www.digikey.com/en/articles/techzone/2015/apr/the-advantages-and-drawbacks-of-dc-to-dc-voltage-converters-with-integrated-inductors

An LM has awesome ripple rejection as evidenced by its ability to run on a DCC layout. A DCC signal is the very definition of a highly rippled supply line. The LM functioning proves Ring incorporates sufficient supply rail smoothing in the LM circuit. No reason to think they wouldn't do the same in the other components. I don't think you have anything to worry about with the up converter other than it will waste a little more electricity as heat.

$18 bucks for a fully conditioned power supply is still the better way to go however.

[Alan]

What is the net effect of lower voltage at the motor? Poor performance or just a lower top speed?

Lower top speed for sure but that is rarely a problem. Models run too fast anyway unless you have a gigantic layout. I'm with Bill, I have my locos dialed way back so their top speed is more correct for the curve radii of my layout. They don't move fast but what's your hurry? The end of the layout is less than 100 track feet away! 

The performance issue is something Kevin may be able to shed light upon with his battery deal. The LM uses PWM. So, even at speed step 0.1% there is still full track voltage delivered to the motor however briefly. The beauty of PWM is the ability to turn a motor very slowly because the full voltage burst overcomes internal friction and loading on the motor. Something low voltage can't do. With reduced voltage the ability to nudge a motor is also reduced. This begs the question: Is there a slow speed operational difference of a loco between 14.8V and say 12V? The math says there must be. Curious what the eye says.

I spent way too much time and money making my power system work like tits-on-ritz so I will not be able to definitively answer this question. I can say LM equipped locos creep along very well at 14.8V.

[William Brillinger]

$18 bucks for a fully conditioned power supply is still the better way to go however.

Same question: Are there going to be any issues using AR's etc with these?

[Alan]

Absolutely not.

RP is selling the same thing just in different packaging.

[TwinStar]

What is the net effect of lower voltage at the motor? Poor performance or just a lower top speed?

Lower top speed for sure but that is rarely a problem. Models run too fast anyway unless you have a gigantic layout. I'm with Bill, I have my locos dialed way back so their top speed is more correct for the curve radii of my layout. They don't move fast but what's your hurry? The end of the layout is less than 100 track feet away! 

I model the Twin Star Rocket. She would hit the top of the siding at 100mph and still make the platform for her station stop! I like to be prototypical.

[KPack]

The performance issue is something Kevin may be able to shed light upon with his battery deal.

Here's what I've noticed so far with a battery:

1.) The top speed is a bit lower, but that is no big deal for me....like others I lower the top speed on all my locomotives to somewhere between 60-70%.  That leaves me plenty of room to play with it, but since this locomotive and it's sister unit will be running locals and switching industries, I really don't want them to go fast.

2.) Start voltage is affected.  I had to up the start voltage in order to get the locomotive moving.

3.) Pulse width modulation is affected.  I couldn't put my finger on it while testing my rig, but Alan identified it.  I noticed the locomotive wasn't starting as smoothly as it did before and would require a bit more "umph" to get it rolling (you can see this in the video).  Once moving, it will glide along as slowly as I want.  But getting everything moving initially takes a bit more power.  It has to be that the motor is only given 12V instead of the normal 14.8V, and this doesn't quite overcome the friction of a static locomotive as easily as 14.8V does.

I run on a friend's DCC layout periodically and for whatever reason he has his Digitrax set up to give something like 16-17V to the rails.  I'm at the upper end of Railpro's safety net when I run there (constantly getting a overvoltage warning).  The locomotives take off immediately upon minimal throttle, whereas on my own rails they crawl along smoothly.

-Kevin

[TwinStar]

I run on a friend's DCC layout periodically and for whatever reason he has his Digitrax set up to give something like 16-17V to the rails.  I'm at the upper end of Railpro's safety net when I run there (constantly getting a overvoltage warning).  The locomotives take off immediately upon minimal throttle, whereas on my own rails they crawl along smoothly.

-Kevin

That's too high. Does he have it set to O scale? I know an N scale setting will give under voltage alerts.

[Alan]

I model the Twin Star Rocket. She would hit the top of the siding at 100mph and still make the platform for her station stop! I like to be prototypical.

Too funny

[KPack]

No, I checked and it's set to HO.  I flipped it to N a few times while I was over there running and that put it right on target.  Problem is when I do that it messes with all his settings on his reverse loops.  So I just run on the high voltage and keep an eye on the module temps.  Never had an issue with it, which speaks to Ring's engineering on the LM.

-Kevin

[Alan]

Never had an issue with it, which speaks to Ring's engineering on the LM.

Agreed. It also speaks to the general robustness of today's electronic components. Manufacturing marvels they are.

When I was designing/testing my benchmade power district circuit breaker design I put an LM through an electrical torture test. I bought the module just for that purpose fully expecting it to fail or be damaged from the abuse. The poor thing was exposed to probably hundreds of short circuits, fully stalled motor tests, and at a wide range of breaker trip currents. Once, a component choice mistake of mine caused the breaker to go into oscillation. The LM was being turned on and off at a pretty high frequency for several seconds before I realized what had happened. It came through all this unscathed! It is in an operational loco today doing just fine. RP LMs are bulletproof.

Couldn't help but think of all the forum posts where someone says they fried a DCC decoder. I now know the only way to fry a LM is with a torch!

http://www.lkorailroad.com/circuit-breaker-and-block-detector-final-units/

[TwinStar]

No, I checked and it's set to HO.  I flipped it to N a few times while I was over there running and that put it right on target.  Problem is when I do that it messes with all his settings on his reverse loops.  So I just run on the high voltage and keep an eye on the module temps.  Never had an issue with it, which speaks to Ring's engineering on the LM.

-Kevin

That's interesting. All we run on top of with Free-mo is Digitrax. I haven't seen voltages that high that I can recall.

[TwinStar]

I successfully installed my first KA into a Proto E7 last night. Everything worked great. I appreciate all the info posted on this thread in order to make this happen. It is pretty cool pulling the loco off the track and watching it run across the table on no rails! I'll continue installing them in my other E units tonight.

[nodcc4me]

Jacob, if possible, would you please post a photo of your install. IIRC the Proto E7 didn't have much room. I had to remove the factory board just to fit the LM in there. I see that the KA-4 is much smaller than the KA-3. Is there any reason not to use the KA-4?

While  we are discussing KA, BLI Blue Line locomotives have KA capacitors installed alongside the circuit board, which also have 8-pin connectors. Has anyone installed an LM in a Blue Line loco? If so, does the KA do the job?

[TwinStar]

Al:

I'm trying but apparently I can't load photos here for some reason and it's been so long since I've had to use image hosting that I can't remember who I used to use.

I'm not ignoring the request but trying to remember how to do this.

Jacob

[Alan]

Bill has you covered. Posting pictures: http://rpug.pdc.ca/index.php/topic,11.0.html