Blinking Green Lamp on CW80

@Vernon Barry posted:

No problem with your transformer- it's YOU. It's telling you that YOU are connecting a load and as you turn up voltage- that pesky OHM's LAW kicks in, amperage increases with voltage and you are hitting the limit.

This is like keeping on driving when the oil light is on in your car dash.

Fix the problem- reduce your load, or get a transformer rated higher for the load.

Agree with Vernon's analysis, but the fact that it apparently worked fine at 40% before, but now will not light the lights and overloads the transformer, says to me something may have gone wrong with the wiring and/or accessories. ISTM a dozen or so incandescent bulbs should not be at the ragged edge of what an 80 watt transformer can handle, so I'd recommend inspecting and testing each building separately for shorts or other emergent problems, then reconnect them one at a time to the transformer until the problem resurfaces, and troubleshoot from there.

Assuming no short or other obvious problem surfaces, you just might mitigate the load issue by substituting plug-in LED equivalents, or splitting the accessory load with another small transformer. Good luck, in any event!

Steve and Vernon,

Thank you both very much for your rapid response, diagnosis and suggestions.  I truly appreciate the feedback.

Vernon, your point about load is well taken.  I agree with the inevitability of Ohm’s law, but somehow I just never thought of it when trying to figure out the problem.

Steve, as you suggested, I'm checking all the wiring from the transformer to the terminal block, and from the block to the individual building lights.

@Bob W / cprail posted:

Steve and Vernon,

Thank you both very much for your rapid response, diagnosis and suggestions.  I truly appreciate the feedback.

Vernon, your point about load is well taken.  I agree with the inevitability of Ohm’s law, but somehow I just never thought of it when trying to figure out the problem.

Steve, as you suggested, I'm checking all the wiring from the transformer to the terminal block, and from the block to the individual building lights.

Bob- If you haven't added any new accessories/ lights but a transformer that used to work doesn't anymore. I'd replace it. The old CW's have been known to have issues.  A little math to calculate the wattage will shed light on your issue as well.

If you are just using this for lighting, you can set a fixed voltage on the accessory posts and see if it stays in operation.

The accessory voltage was set to 12 volts at the factory.
1. Bring the throttle all the way back to turn off the power.
2. Press and hold down the DIRECTION, WHISTLE/HORN, and BELL buttons
on the Controller. Refer to Figure 4 for the location of these buttons.
The green light on the Transformer will flash and track power will turn off.
3. With all three buttons held down, raise the throttle slowly until you reach
your desired accessory voltage.
4. Release the buttons once you have reached your desired voltage.
The accessory turns off, and the solid green light indicates that you have set the accessory
voltage.
5. Bring the throttle all the way back to turn off the power.
The voltage will momentarily increase, briefly causing the lights to shine brighter or the
motors to operate faster, before returning to the set level.
At this point, increasing the throttle again will control track power.

Bob

I'm not saying the CW80 is a perfect transformer, far, far, far, from it.

That said, it has some pretty basic known failure modes- either stuck full on output- from a failed TRIAC that just conducts full power with no control, or no power of any kind. I'm not saying it's impossible for other failures, but implying the current sensing circuit for overload protection somehow went wonky- I'm not buying it.

Again, the testing right here in the topic basically proved the transformer was STILL properly varying power, and just that when the output increased- so did the amperage draw- to the point we reached overload.

Where this went wrong, is 2 people read the same manual, and get insanely different ideas of what that means- and you said this: "The CW manual says the blinking lamp indicates the transformer is unable to produce the power requested."

Again, clearly, in the first post, you took that to imply the transformer was faulty and could not supply the power. The "correct" answer is- the transformer is trying to supply the commanded power, and your load began to pass such current that it hit the internal limit, the transformer safety mechanisms and overload sensing is trying to warn you "Hey dude, you are messing up" and instead of seeing that and thinking- hey, I should probably look at the load and wiring- instead you made a post here asking how to fix your transformer.

Again, the reason for me pointing this out- I perceived the path you were heading down, and your own explanation- you were putting yourself and your wiring at risk. I probably could have done a better job on tone and better explaining, but it was around midnight, so I wasn't at my best. Again sorry for snapping and the tone, but I perceived the path you were on was dangerous, you were taking a warning sign completely wrong, and so I was trying to convey a level of urgency.

I cannot stress this enough- the green flashing is a warning indicator- as was the cut of power when the warning indicator is allowed to continue operating in overload for longer than a few seconds. It's not an indicator the transformer is failing, it's an indicator you are overloading the circuit.

Suppose you follow the advice and install a new, or possibly a larger transformer to power this circuit. If it is a wiring fault- the increased power available and higher overload point could lead to a wire getting hot enough to melt or cause a fire.

And for the record, I have done a little bit of transformer testing, and overload comparison of the old and new CW80 models.

This is one of those posts and yes, focus is on the new CW80, however it's clear from side by side testing, the older CW80 firmware functions of overload sensing and power cutoff are basically very similar.

https://ogrforum.com/...0#161631098285972750

@Vernon Barry posted:

Also, specific short circuit and overload testing I performed on the new version of the CW80.

Testing using a common 3D printer heated bed that has either 12V or 24V paths. The 24V path is 6 Ohms cold resistance, and the 12V path is 3 Ohms resistance.

Some quick tests using a Fluke 101+ meter (doesn't have AC current measurement so going on voltage over known resistance)
With nothing more than a small light bulb for load output is 18.98V AC RMS max throttle
With the heated bed 6 Ohm load and the lightbulb output dropped to 18.0V and did not trip overload. 18V into 6 Ohm load should be about 3A = roughly 54 Watts
With the heated bed 3 Ohm load, raising the throttle to about 50% on the lever results in 7.5V and not quite tripping the red blinking overload light. Raising it higher to just above 8V triggers the red light overload blink but power is still being provided for 5 seconds. I ran this test several times, a slow load based overload trips in 5 seconds. Just did another reading by removing the load at this setpoint to measure the unloaded voltage VS loaded voltage at the trip point. Test condition throttle at 50% mark, results in 10V unloaded, and then adding the 3Ohm load drops to 8.5V with the light blinking. In theory this is about 3.33A, I didn't have my good ammeter on hand for actual measurements.
The bad part IMO, the overload light blinking starts a 5 second sequence and then power is dropped.

Further short circuit testing:
Raise throttle to 100% with 6 Ohm load plus lightbulb indicator.
Heated bed dual load is approximately 2 Ohms.
Simulate overload with 3 Ohm in parallel to existing 6 Ohm Load= Light dims and voltage is about 9V output, red light blinks, holds load for 5 seconds, then output is off, red light solid. Must turn handle to 0 to reset.
Simulate intermittent short using 3 Ohm load on top of 6 Ohm load. Counting seconds how long the intermittent short is loaded.
This is basically a 2 Ohm load.
1 Second, light blinks, returns green after overload is removed. Power is not interrupted.
2 Seconds, light blinks, returns green after overload is removed. Power is not interrupted.
3 Seconds, light blinks and even if load is removed, continues blinking for 5 Seconds and then power shuts down and red light becomes solid.
Again, the 3 second test, the power continues for 5 seconds and then is shut down.

Using 30 feet of 14 gauge solid house wire as a short load- touching it across the terminals instantly blinks overload switching to solid red and output is shut down.
Again, a very low resistance short results in an instant shutdown.

Moral of the story?????

CW-80's make excellent door stops for the train room......

Vernon and Bob (and RSJB) – Thanks for the clarifications, I need all the help I can get as an model RR electrical novice.  For what it’s worth, I think this actually an interesting problem in logical deduction.

Yes, the manual says “The green light will begin to flash if you exceed the power limit of the transformer.”

However, I see 2 entirely different deductions from the statement.  One is that the transformer is working fine, but something has happened to increase the load to cause it to go beyond what the CW can deliver.

The other deduction is that the load has not changed, but the CW is unable to produce the required power.

In my case, the CS worked perfectly fine for many (15 plus) years until the building lights stopped shining and the CW light started blinking.  Because I couldn’t imagine what could possibly have changed without ANY alterations, additions or interventions on my part in wiring or lighting on what the CW is wired to, and that it worked perfectly all those years...I concluded (erroneously) the problem was the CW, hence my question in the post.

I can also see the possibility though that something might have changed beyond my knowledge that is causing the increased load, but what?  Could it be a rectifier failure (for AC to DC conversion for the building LEDs)?  Bulb burnout and associated short?  Wires wearing out?  None seem likely to me, but my experience with these problems is zero.  I do note that the layout has gotten very, very light use since it was built in the 2006-2010 period, no more than an hour every few months.  So any insight here would be greatly appreciated.

If the problem is the wiring to the buildings and the lighting, I’ll uproot them to check them out.  Naturally, the buildings are all at the most inaccessible spot on the entire layout.  See the pic attached, buildings in question are circled in red and the nearest access hatches are a real stretch (they weren’t when I built the layout15+ years ago, but age is making those stretches a real challenge).

In any event, thanks for your interest and perseverance --

@Bob W / cprail posted:

I can also see the possibility though that something might have changed beyond my knowledge that is causing the increased load, but what? Only you can answer this with hands on testing and knowledge of your layout and wiring.

Could it be a rectifier failure (for AC to DC conversion for the building LEDs)?  Absolutely, electronics can and do fail, usually there is some root cause or defect, but sure, it easily could short.

Bulb burnout and associated short? Sure, I have seen shorted bulbs. Mostly it's wiring, but there are absolutely scenarios where anything electrical can fail. Again, I have seen a grain of wheat bulb short, rare yes, but not impossible.

Wires wearing out?  Less likely the "wire wearing out" but insulation can fail, harden and crack, wires can get chewed on or pulled and then short.

None seem likely to me, but my experience with these problems is zero.  I do note that the layout has gotten very, very light use since it was built in the 2006-2010 period, no more than an hour every few months.  So any insight here would be greatly appreciated.

Again, the thing here is, we have no wiring diagram, we don't know your power distribution plan, we have no idea the state of things- did something get pulled or insulation failing?

You are going to have to test a few buildings at a time.

Again, I'm not saying it's impossible your transformer failed, but the symptom was it still tried to vary power, it still was in theory outputing power, and when you raised the handle higher it sensed the overcurrent and shut down.

During any of that- did the lights work or not work- even if dim?

Again, what I know is, I would bench test the transformer with a simple incandescent light bulb.

If it varies the power and can go full on and full off with a light- 99% chance it's working correctly.

I also don't know your layout wiring and what you have for transformers, but if you wire another one into this circuit, I would measure amperage using a capable meter and/or use a fuse or breaker in series just in case this is shorted load.

Edit:

I'll also add, if you really do have hard to get to areas of the layout (I get it, we all end up here sometimes) taking that extra step and doing individual wire feeds for buildings or accessories, and then fuses, PTCs, or circuit breakers in each branch or leg- could limit such a problem to one failed building or sign. I get it, hindsight is 20-20, but again, when doing a big layout, tons of buildings and lights, rather than one huge parallel circuit, breaking it up into buildings or groups of buildings, spending the time and money on additional fuses or breakers (and yes, I know that all adds up) but hopefully limits the "outage" to one section or building, rather than a larger and more obvious widespread blackout on your layout lights.

Thanks very much, Vernon, I appreciate your interest and help in getting to the right solution.

I should have explained the full situation in my initial post.  The CW is dedicated to lighting the buildings in question, nothing else.  The distribution wire is 16 ga to a terminal block, and from there it's 22 ga either to 1) the rectifier for the building LEDs, then more 22 ga to distribute to the individual LEDs, or 2) 22 ga all the way from the terminal block to individual AC building lamps.

I wish I'd made notes of why I did things the way I did when I built the layout all those years ago...but in the hurry to get it built back then, I didn't. and today I can't remember why I did what I did.  Now I know better if I can muster the determination to start over on a new layout!

I did some more investigating of the CW by disconnecting its leads to the actual load, and just checking the voltage on the A and U terminals with my multimeter.  As you no doubt would have predicted, when the throttle is off, it registers 0 volts, and when full on the reading is 18 volts.  So you were absolutely right -- the problem is not the transformer.  I'm thinking the CW is just not powerful enough for all the building lights (and street lamps) connected to it, and the solution is to buy a more powerful transformer.

Before that, however, I was planning on seeing see how the CW reacted as I disconnected each pair of leads to the lights, one at a time, in the hopes of isolating the problem.

Vernon - re:  edit of your last post.  Great suggestions -- circuits with fuses would have been really helpful finding the problem when something goes wrong as it has for me.  Wish I'd had the vision to research wiring more completely when I was originally building the layout, rather than just what I learned from books on simple wiring with only a few accessories and buildings.  But it's not too late to start doing it right as I dig into the current problem.

Thanks again.