Keep Alive installation w/ Railpro

[nodcc4me]

I would also like to thank Alan and everyone else who contributed to this thread. I just installed my first KA4 in one of my oldest engines, an AHM Rivarossi RS2 that is about 45 years old. It has sintered wheels and one-truck pickups. That old locomotive sputtered along and the prime mover was cutting out about every 3 seconds. I was about ready to remove the LM2-s and park it on the layout. With the addition of the KA, it runs like new, never stalls and the sound never cuts out. It does take a bit more power to get going but runs smoothly, even at slow speed. 

[KPack]

Bring back an old topic for an update.

I remember Bill saying somewhere (might have been in an email to beta testers) that he has changed to adding KA's to LM-3S's without a bridge rectifier so that there isn't a drop in voltage to the module.  Apparently the drop in voltage was causing the loco to not play nice with others.  Bill can you confirm?

I have a KA4 and a bridge rectifier installed in two different locomotives and did some testing over the past few days to see if I had the same issues.  I did not.  The KA'd locos MU'd just fine with any others and there was no perceptible difference in behavior.  The KA'd loco was not slow on starting and always ran perfectly with any other loco (this includes a lashup of 5 very different locomotives).  It did fine as either a leader or a follower.

The only thing I can think of that would cause such a difference between my experience and Bill's experience is that on both of my locomotives were "fresh" installs.  Meaning, both modules had all data erased (previously used), new programs and sounds loaded, and the Full Load Motor Current was redone.  Bill, did you redo the Full Motor Load Current when you installed a bridge rectifier and KA?  I think that may have made the difference for me.  I assume the FMLC is different for a locomotive that is seeing less voltage (12.9 on the readout).

-Kevin

[William Brillinger]

Kevin,

I may have been hasty with my conclusion that the Bridge Rectifier was causing issues between locomotives.
I will do some testing this evening to confirm how my units are behaving.

Yes, I reset the FLMC values after making any changes to a locomotive.

One thing I am wondering about: I recall reading that you have adjusted the startup speeds. I have not done this, and it may be a factor.

[KPack]

I adjust the start voltage depending on the locomotive.  I try to get it moving at about 5% throttle or so.  Most of them are set between 7-11% start voltage.  I also drop my top speed on almost all of them to 70% or lower, again depending on the locomotive's gearing and how fast they like to move.  Adjusting the top speed will affect how fast the locomotive moves at low speeds.

Basically I try to get my locomotive to run as smoothly as possible and not take off like a rocket.  Railpro is hands down far smoother than DCC ever was, and far better at slow speed control.  I can have a full MU set crawl along at a snail's pace perfectly in unison.  Never could get that will DCC.

-Kevin

[Alan]

I adjust the start voltage depending on the locomotive.  I try to get it moving at about 5% throttle or so.  Most of them are set between 7-11% start voltage.  I also drop my top speed on almost all of them to 70% or lower, again depending on the locomotive's gearing and how fast they like to move.  Adjusting the top speed will affect how fast the locomotive moves at low speeds.

-Kevin

I've found when working with new locos it is sometimes necessary to revisit these two settings after the unit gets well broken in. I have a 22"R loop for break-in but still like to tune after the powertrain has some miles on it.

[William Brillinger]

I may have been hasty with my conclusion that the Bridge Rectifier was causing issues between locomotives.
I will do some testing this evening to confirm how my units are behaving.

It appears my issues with my units that still have LM-2S's are more related to a surging issue. This is an issue with the locomotive, not the RailPro module. It's one of my Athearn Genesis GP38-2W's that hit the floor a while back during an op session. It seemed like it was ok at the time, but there might be something broken in a gear tower.

[William Brillinger]

Just to update this thread a bit...

Here is how I am installing KA's in my LM3 series units: https://rpug.pdc.ca/index.php/topic,383.msg2872.html#msg2872

Yes there is a possible issue with short protection, but this is what Tim Ring designed these inputs for.
If you are concerned about this, then use the Bridge Rectifier and put the KA's on the outside of the LM power inputs.

WARNINGS:

• This only applies to RailPro LM3 modules. Older Modules need a Bridge Rectifier to install a Keep Alive
• This will probably void your warranty from Ring Engineering.

Wire the Keep Alive as follows:

Module 9 Pin Blue (Common Wire) to KA3/4 Blue +12v Wire
Module 6 Pin Yellow (Negative Wire) to KA3/4 Black/White Ground Wire

[nodcc4me]

Looks simple enough. It's great that we have some electronic whiz kids on here.  Thanks Bill.

[TwinStar]

Kevin's original diagrams showing the wiring schematic for an LM-2 are now missing from this thread. Are they stored somewhere else?

Thanks.

[William Brillinger]

Ah yes, the photo bucket issue.

Here are my images for wiring an LM-2 with bridge rectifier:

[TwinStar]

Thanks Bill. I also found I don't have another KA. Another order coming your way!

[TwinStar]

Where did the KA install with bridge rectifier diagram go? I can't find it after the rearrangement.

Thanks.

[Alan]

Where did the KA install with bridge rectifier diagram go? I can't find it after the rearrangement.
Thanks.

Bill's Nov 9 reply two replies above yours in this thread.

[William Brillinger]

In addition to the comment above with the diagrams, you can find a post under the Installations board called Installing a TCS KA3 in Athearn DCC Ready Genesis GP38-2 with a bridge rectifier

Or, I have the instructions also posted on my website at the bottom of this page:
http://pdc.ca/rr/catalog/product/wiring-harnesses-keep-alives-and-other-accessories/63

[KPack]

Since this topic was brought back up, I thought I'd provide an update on the KA's.  They work fantastically with the LM-2S and a bridge rectifier.  No problems whatsoever.  They MU great, never loose power, and were well worth any trouble it was to hook them up.  Part of me wants to convert my entire fleet!

-Kevin