MTH smoke unit fan operation a few questions

If the fan impeller is loose on the shaft, the impeller will spin after the motor brakes. Usually, the tell tale sign is ok idle smoke, but kinda weak, or anemic chuff blasts …..as far as the whistle steam motor, you could try a tiny tiny drop of oil on the shaft ends to hope it’ll get quieter….

Pat

#1 lube the fan motor. I use a drop of 107 right on the motor shaft output load bushing. Again, one drop, right on the shaft so that it lubes that upper bushing. I typically remove the pressed on fan using needle nose pliers, lube the shaft and bushing, then reinstall the fan.

#2 yes it coasts. Perfectly normal.

@harmonyards posted:

If the fan impeller is loose on the shaft, the impeller will spin after the motor brakes. Usually, the tell tale sign is ok idle smoke, but kinda weak, or anemic chuff blasts …..as far as the whistle steam motor, you could try a tiny tiny drop of oil on the shaft ends to hope it’ll get quieter….

Pat

So is the motor supposed to brake after each chuff?

@jini5 posted:

I am wondering if I need a little wick blockage so the coasting impeller wont have enough force to push smoke out the exaust hole. Perhaps I should partially block the exaust hole so the push of the fan(when syncing with the chuff) will push smoke out the hole while the coasting of the impeller will not have enough force to push smoke out the stack.

I would say do not do any of that. NEVER restrict airflow in a smoke unit.

MTH uses dynamic braking on the smoke fan motor, so unless you're running at a fairly high speed, the smoke impeller should visibly stop.  As others have said, it's probably slipping on the shaft.  If it's doing that, it won't be long before you don't get chuffing at all, but rather it'll be so loose it won't run except at idle when there's no start/stop.

@jini5 posted:

So is the motor supposed to brake after each chuff?

In theory it brakes- but that's FIRMWARE dependent. Yes, in the past many (most/all) of them did have dynamic braking. That said, this is a newer engine with steaming whistle. So it does what this new board tells it to do.

@Vernon Barry posted:

#1 lube the fan motor. I use a drop of 107 right on the motor shaft output load bushing. Again, one drop, right on the shaft so that it lubes that upper bushing. I typically remove the pressed on fan using needle nose pliers, lube the shaft and bushing, then reinstall the fan.

#2 yes it coasts. Perfectly normal.

Vernon, nice diagram. I noticed the note next to the DC fan about counterclockwise rotation. Mine spins clockwise. See my pic of my top view. Am I incorrect with the curvature of the impeller blades? Do I need to reverse the leads on the motor?

@jini5 posted:

Vernon, nice diagram. I noticed the note next to the DC fan about counterclockwise rotation. Mine spins clockwise. See my pic of my top view. Am I incorrect with the curvature of the impeller blades? Do I need to reverse the leads on the motor?

I would say clockwise is correct in your case. This is not a super high pressure fan system, but again, the general fan housing and exit is more geared towards clockwise rotation and this gives the best airflow IMO.

https://en.wikipedia.org/wiki/Centrifugal_fan

https://en.wikipedia.org/wiki/...:Centrifugal_fan.gif

Is a drop of superglue on the tip of the shaft, then reseat the impeller the fix for a loose impeller?

@jini5 posted:

Is a drop of superglue on the tip of the shaft, then reseat the impeller the fix for a loose impeller?

I put a tiny drop inside the impeller then quickly reseat it, …..don’t put it on the shaft!!…the impeller will push the glue onto the bearing, then it’s boom boom out goes the lights….only caveat, you get one shot at getting it right, and if it fails, you’ll need a motor and an impeller,…….I’ve gotten to gluing them on my own stuff, as I was plagued with loose impellers seems like every build I did …..

Pat

@Vernon Barry posted:

In theory it brakes- but that's FIRMWARE dependent. Yes, in the past many (most/all) of them did have dynamic braking. That said, this is a newer engine with steaming whistle. So it does what this new board tells it to do.

I can assure you that the standard PS/3 code still has dynamic braking for the main stack.  I don't know about the steaming whistle, I've truthfully never given it a thought as I only have a couple of MTH locomotives with that feature.  The reason the PS/3 board has a dual-FET for the smoke fan is to implement the dynamic braking.

@harmonyards posted:

I put a tiny drop inside the impeller then quickly reseat it, …..don’t put it on the shaft!!…the impeller will push the glue onto the bearing, then it’s boom boom out goes the lights….only caveat, you get one shot at getting it right, and if it fails, you’ll need a motor and an impeller,…

Exactly, gluing the motor bearing is the wrong way to go!   If you're going to glue it on, probably best to put a drop of light oil on the bearing first as you won't be getting in there if it starts squeaking later.

@gunrunnerjohn posted:

I can assure you that the standard PS/3 code still has dynamic braking for the main stack.  I don't know about the steaming whistle, I've truthfully never given it a thought as I only have a couple of MTH locomotives with that feature.  The reason the PS/3 board has a dual-FET for the smoke fan is to implement the dynamic braking.

Yep, …I’m not sure where our buddy Vern got the idea from that they coast, but the pump shots tell another story, ….clearly you can see dynamic braking in action by the defined puffs at each chuff, …..especially at the lower speed steps,…..I’ve built a couple circuits for fan motors off cherry switches, with & without dynamics, and the results are night & day,….

Pat

@harmonyards posted:

Yep, …I’m not sure where our buddy Vern got the idea from that they coast, but the pump shots tell another story, ….clearly you can see dynamic braking in action by the defined puffs at each chuff, …..especially at the lower speed steps,…..I’ve built a couple circuits for fan motors off cherry switches, with & without dynamics, and the results are night & day,….

Pat

The reason I said what I said is- newer PS3 with whistle steam is using a combined boiler board with steaming whistle secondary output.

I cannot be sure on this model (20-3807-1), but it is a 2021 engine, and my recent own 2022-23 engines like the PRR J1 with steaming whistle have the new AE1000E37 combined boiler board, VS previous models having the "standard" AE1000E32 Boiler board+ steaming whistle board AG1500002. We have not seen what type this engine is (none of the pictures in this topic show the boiler board).

In some ways, sure, why would they change the main stack smoke electronic section of the board? But it is now a different board.

Again, the thing is, over time and very recent models, MTH has made changes. The old way, yes, even non-steaming whistle engines all used the same basic boiler board to run the main stack smoke. In newer models, there is a different board. I haven't reverse engineered the new board to the point of being able to say beyond a shadow of doubt I can defend it brakes the smoke motor to the same effect as previous boards.

VS +

Again, in theory, the new combined board is just that, the old board plus steaming whistle in one board. But to say that it's identical, it works 100% the same way, I personally cannot say that with the same level of confidence.

Bottom line, I'm still trying to figure out how we got here?

What was the original symptom that resorted to replacing the fan motor in the engine in the first place?

How after replacing the motor, did we have worse problems (squealing sound and "coasting fan") to the point of creating this topic?

Was either of those the original reason for replacing the motor?

@Vernon Barry posted:

Bottom line, I'm still trying to figure out how we got here?

What was the original symptom that resorted to replacing the fan motor in the engine in the first place?

How after replacing the motor, did we have worse problems (squealing sound and "coasting fan") to the point of creating this topic?

Was either of those the original reason for replacing the motor?

Now that’s a good question, ……😉

Pat

If you own about 3 or more MTH engines that have smoke units, at some point in time if you are going to self service them- having ALL the spare parts on hand makes a lot more sense rather than buying only a fan motor because one went bad. Shipping cost alone on multiple orders kills you. https://www.mthpartsandsales.com/shop/search

I typically have minimally these parts on hand before touching an MTH smoke unit, because you might need any one of them. Even the act of opening up a smoke unit can rip the gasket. Try to get the 5 packs and not the single when possible (same part number ends in 5).

Also, would would recommend keeping fiberglass rope wick in bulk on hand as I almost always end up replacing it too, but just buy that in bulk elsewhere.

@harmonyards posted:

Now that’s a good question, ……😉

Pat

I started this topic. I am sorry if I caused problems amongst friends. I was able to quiet down the fan by applying oil and raising the impeller on the shaft (whistle steam). I put the loco back together . All seemed fine til I turned on the stack and noticed that I could hear the fan bursts (with volume turned down) syncing to drivers but not smoke not pausing between chuffs. This didnt look right. The above posts suggested the impeller is slipping on the shaft. I made an attempt to remove the impeller with needlnose pliers. I am sure I could have pulled it off, but I found it to be tight (seemed like a good amount of pressure without it coming off). I am assuming the impeller is not spinning on the shaft. I would like to post a video but have never figured out how to do that on this forum. I could text someone the video showing the fan and heater seperated. The coasting is visible and so are the fan pulse/chuff sound. This loco has 2 boards mounted to the ceiling  ( a 30 pin and 8 pin board and another board that seems dedicated for the whistle steam)  Since the impeller is tight and the impeller is coasting and not stopping between chuffs, I suspect this board. (30 pin and 8 pin) Again, I am truly sorry for any issues I caused . I just would like this fixed.

@jini5 posted:

I started this topic. I am sorry if I caused problems amongst friends. I was able to quiet down the fan by applying oil and raising the impeller on the shaft (whistle steam). I put the loco back together . All seemed fine til I turned on the stack and noticed that I could hear the fan bursts (with volume turned down) syncing to drivers but not smoke not pausing between chuffs. This didnt look right. The above posts suggested the impeller is slipping on the shaft. I made an attempt to remove the impeller with needlnose pliers. I am sure I could have pulled it off, but I found it to be tight (seemed like a good amount of pressure without it coming off). I am assuming the impeller is not spinning on the shaft. I would like to post a video but have never figured out how to do that on this forum. I could text someone the video showing the fan and heater seperated. The coasting is visible and so are the fan pulse/chuff sound. This loco has 2 boards mounted to the ceiling  ( a 30 pin and 8 pin board and another board that seems dedicated for the whistle steam)  Since the impeller is tight and the impeller is coasting and not stopping between chuffs, I suspect this board. (30 pin and 8 pin) Again, I am truly sorry for any issues I caused . I just would like this fixed.

You ain’t causing no problems at all, …..this is everyday, 7 days a week …..nobody’s mad at anybody as far as I know,…..

you can add a video, at the bottom of your reply when you’re typing,  before you hit publish, see the little paper clip,…..that is the add attachments window. Then you can pick the file from your library …….just watch the video length, I believe the file limit is 100mb ……

Pat

I wonder if what you’re experiencing is the fact the Bigboy is a 4 cyl engine, and where do you have the chuffs set in the remote?….set on 4 chuffs a 4 cyl engine is gonna make double the chuffs per revolution,….

Pat

@harmonyards posted:

I wonder if what you’re experiencing is the fact the Bigboy is a 4 cyl engine, and where do you have the chuffs set in the remote?….set on 4 chuffs a 4 cyl engine is gonna make double the chuffs per revolution,….

Pat

I can hear the fan puff in sync with the articulated drivers. It is a double chuff at times. I have the remote set to 4 per revolution. However, I did set the rate to 1 per revolution and at 1 scale MPH the impeller coasted to a stop just beffore the next chuff.  It is obvious that the impeller coasts and does not have braking.

@jini5 posted:

I started this topic. I am sorry if I caused problems amongst friends. I was able to quiet down the fan by applying oil and raising the impeller on the shaft (whistle steam). I put the loco back together . All seemed fine til I turned on the stack and noticed that I could hear the fan bursts (with volume turned down) syncing to drivers but not smoke not pausing between chuffs. This didnt look right. The above posts suggested the impeller is slipping on the shaft. I made an attempt to remove the impeller with needlnose pliers. I am sure I could have pulled it off, but I found it to be tight (seemed like a good amount of pressure without it coming off). I am assuming the impeller is not spinning on the shaft. I would like to post a video but have never figured out how to do that on this forum. I could text someone the video showing the fan and heater seperated. The coasting is visible and so are the fan pulse/chuff sound. This loco has 2 boards mounted to the ceiling  ( a 30 pin and 8 pin board and another board that seems dedicated for the whistle steam)  Since the impeller is tight and the impeller is coasting and not stopping between chuffs, I suspect this board. (30 pin and 8 pin) Again, I am truly sorry for any issues I caused . I just would like this fixed.

Just a thought.  Did you try blasting a puff of air down the stack?  I have had issues with bubbles blocking the stack especially with a lot of fluid in the chamber.  The puff of air started the smoke pouring out again.

John

@jini5 posted:

...I would like to post a video but have never figured out how to do that on this forum. ...

@harmonyards posted:

...you can add a video, at the bottom of your reply when you’re typing,  before you hit publish, see the little paper clip,…..that is the add attachments window. Then you can pick the file from your library …….just watch the video length, I believe the file limit is 100mb …… Good point on the length - video size goes up quickly

Here's a link on OGR (from the technical forum) related to what @harmonyards suggested. Since you've successfully posted pictures, it shouldn't be any different.

https://ogrforum.com/...s-from-your-computer

Here's a sample, I just did an Add Attachments with this video.  This works for any video under 100mb.