LM-4S-G Erratic behavior/Intermittent "Cannot Connect"

[gregeusa]

So the brushless fans have an internal oscillator to create the "shifting magnetic field" that is the "replacement" for a commutator and brushes.

It has been noted that some of these electronic circuits can cause electrical noise in sensitive circuits.

Putting an inductor in one of the power leads to the fan could solve the issue if the RP module is sensitive to conducted rfi.

If the RP module is sensitive to radiated rfi, then you need shielding.

There are simple methods to determine which (if this is the issue) is causing the issue.

Do some more verification that disconnecting the fan solves the issue, then I'd be happy to advise on simple step by step to solve the issue and keep the fan.

Greg

[Gibs]

I did, before you edited it.

Stand by my statement, pity you can't.

[gregeusa]

Uhh... Gibs, are you talking to me? I was not talking to you, last response was several days ago, and don't know what your problem is.

Back to the issue, if it's verified that the little brushless fan causes enough noise, it's a sad situation, radiated or conducted.

It would be good to find out what the sensitivity is, and correct it.

Many DCC setups use these fans and they work with no issues.

Greg

[G8B4Life]

Well for just another data point I just did a fan experiment. The hardware is obviously not the same but what we're testing for is.

I put an 80mm brushless DC fan right next to an LM-2S. Testing with the fan powered by a battery (radiated RFI) and powered by the same PWR-56 as the LM-2S (conducted RFI) presented no issues. It connected every time and responded correctly to commands.

I have a 40mm fan here somewhere. If I can find it I'll test that one too.

- Tim

[gregeusa]

The problem with these fans, is they are almost all "no name" products, and can vary wildly.

References to interference from brushless fans:

https://www.rctech.net/forum/electric-road/114069-motor-fan-interference.html

file:///C:/Users/greg.GE/Desktop/emi-emc-umf-dc-fans.pdf

https://arstechnica.com/civis/threads/electrical-interference-from-case-fan-causes-speaker-hiss.620400/

Tons of examples on the net.

Again, different fans, different problems.

Not at all unusual. Google it and see how many hits you get "brushless fan interference"

Greg

[gregeusa]

Tim, I'm beginning to suspect "conducted" RFI, one line of reasoning is that the RP modules have not been shown to have any issues with motor RFI, so radiated RFI would seem to not be a factor.

Conducted RFI through the motor is most likely handled. But put the RFI into the INPUT of the module (battery connected to both RP module and fan) could be an issue.

As I said, the electronics in these cheap brushless fans varies wildly (have you ever opened a fan labelled "ball bearing" and found no ball bearings? I have)

Anyway, let's hear from Jordan. I would suggest he put an inductor on the fan power lead, that should zap conducted RFI if that is the issue.

Greg

[jordanhd87]

Again, now with the fans removed, I don't have any issues running my Railpro locomotives with power fed directly from my CRE-55465 power supply at 23v output to the rails. I've done a few running sessions now, with a mix of my 5 railpro locomotives, for a total of about 8 hours with no issues. If I try running my power supply through my Revo trackside super unit (linear) set to full output to the tracks, I do have issues with my Railpro locomotives losing connection but still running. If I run straight from my power supply (fused) to the rails, no issues with connection. I suspect RP's comms module is VERY finicky with incoming power, since I'm only losing connectivity but the train continues to run (it may jerk to a halt and take off again, but then it keeps running at the last setting and I have to kill the track power to get it to stop). Anyways, my brother and I are doing some testing with a scope, have more to do. But at least I know how to get my Railpro locomotives to run reliably for the time being, even if the root cause is not fully pinpointed.

[JRad]

Just a wild guess here, but since your Revo Trackside receiver uses RF to communicate with the remote, and RailPro uses RF to communicate between loco and handheld, I suspect that radio interference is causing your "Can't Connect".

Seems to me a simple DPDT switch setup would allow you to quickly switch the Revo trackside out of the circuit connecting the track directly to the power supply.

Did you previously mention that the Revo Trackside receiver was in the power supply circuit?  I saw were you said several Revo equipped locos, but I assumed that meant they have on-board Revo receivers powered by straight DC on the track.

In any case, I'm glad you got it sorted out to the point you can reliably run your Railpro locos.

[jordanhd87]

JRad - that's exactly how I have it set up (on a DPDT) which is why I didn't mention it before, because I was getting failures running straight off of the power supply (until I disconnected the cooling fans in the locomotives). I tested it with the Revo trackside unit for kicks and giggles. I don't suspect radio frequency interference being the issue with that, but rather something on the power input side that RailPro doesn't like.

[gregeusa]

So Jordan, are you going to try some small RFI filters on the fan power leads?

https://www.amazon.com/BOJACK-3-5mm-0-8mm-Ferrite-Inductors/dp/B09C25PPBG/ref=sr_1_5?keywords=Ferrite+Bead&qid=1672549215&sr=8-5

https://www.amazon.com/Hanzou-Ferrite-Sleeve-3-5x5x1-5mm-Toroidal/dp/B09CKP2D32/ref=sr_1_197?keywords=Ferrite+Bead&qid=1672549481&sr=8-197

[jordanhd87]

Hi Greg,

I'm going to wait until it warms up a bit and see if I need these fans after all. I was having the overheat issues before v1.05 was released, but wasn't quite warm enough after the update for me to put it through the ringer and gain its trust. If I end up needing the fans I will play around with RFI filtering.