USA Trains Hudson Electrical Drgs & Smoker Voltages - please!!

S

silverfox

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Hi All
Does anyone have a source for USA Trains Hudson electrical schematics and does anybody know what the expected input voltages should be for the smoker power supply PCB?
Thanks - driving me mad!!
 
Wow, never have found those, I have one and it's a rats nest inside.

Does the smoke unit look like this?

tas_unit.jpg

tas_bottom.jpg
 
No unfortunately not, the USA Trains version has a similar layout but a less heavy smoke unit. I haven't got an image but will post one tomorrow when I am back in my workshop.

Thanks Greg
 
Yep, that is a stock USAT smoke unit and regulator board from their diesels.

I was not aware this was ever used in the hudson...is this an untouched loco?

All Hudsons I know of had puffing smoke, that board is constant voltage to the fan and heating element, it cannot "puff" in synchronization.

I think your unit is not what was supplied with the Hudson when new.

Greg
 
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Hi Greg,

This is as new installation, the loco is straight from USA Trains, as I understand it the regulator PCB supplies power to the smoker and a 3rd connection to the smoker provides pulse for the chuff via a reed and the driver axle magnets. It looks like the output is 6 volts DC and the input to the regulator is "raw" track voltage which is worrying as I am advised that this should be 5 - 6 volts- if it over volts then the PCB shuts down as protection in case the smoker runs dry. But hey what do I know!!
 
Hmm... that "regulator board" looks identical to all the ones I have in my USAT Diesels.

There are three 2 pin connectors on the board... one is track voltage input, one is output to the fan, one is output to the heater.

You tell me where the chuff input connector is.

Something is fishy.

As far as I know, all Hudsons, of which I believe there were 2 manufacturing runs, had synchronized smoke, i.e. puffing... it's on their site and in the manual.

The hardware you have cannot do this, nor will it put out large volumes of smoke, since it is a constant voltage to the heater and a constant voltage to the fan. You could pulse the entire board, but you would be pulsing the heater also, which could never give you the desired effect, the heater would cool down too much.

The picture below is a USAT Hudson, you will see that the smoke unit is NOT what you have pictured, and does not use the regulator board you have shown.

Open.jpg


Perhaps USA Trains changed the system in later models, but I doubt it. I would think that they would have updated the web site to remove the reference to the synchronized smoke.

If this is indeed a new locomotive, untouched, then does your manual reference the synchronized smoke?

By the way, in the picture, you can see the smoke unit I indicated before, the TAS unit, similar to but not the same as:
tas_bottom.jpg


The key here is that the TAS units have the electronics on the smoke unit, not a separate board, and have a single large cap. Again, the picture above is a different TAS unit. Between the 2 white plugs you see, is a 3 pin header, with a black jumper on the right 2 pins, that is where the chuff input goes... (this one is jumpered for constant fan speed)

You can also see your USAT regulator board has a two large electrolytic capacitors, (filter input and filter regulated voltages), whereas the TAS unit above and the one in the locomotive picture only has one.

I don't know everything about this locomotive, although I do indeed have one, and have helped others, but as far as I know, what you have is not stock.

So to answer your original question, the input to your regulator board is track voltage... the output seems to be about 6 volts to the fan motor, and my experience is the heater output varies, and it is SUPPOSED to shut off when it runs out of fluid (fan keeps going).

By the way, here is a picture showing you where the heater and fan wires connect to the regulator board:

USAT_smoke_unit.jpg


Greg
 
Hi All,

Thanks for the updates,

Neil, been talking to Phoenix about that drg on the knowledge base seems that it is based on the original smoker fit as described by Greg above and is different now so is not really applicable - thanks.
Greg the loco was delivered new in March this year directly from USA Trains, this was the fit as sent - since then I have upgraded the loco for DCC by fitting a Massoth XXL II decoder - this works fine but the smoker has created an issue - originally hoped to run the smoker on/off from the Massoth navigator - F13 (other functions have sound associated) however this created problems and USA Trains have not been very helpful(!) So I am reverting back to control via the loco switch on the side of the firebox and hoping.......to use the Massoth clock output from decoder output 6 however I need to be clear on voltages etc.

Thanks
 
Wow, so they must have run out of the TAS units, AND did not bother to update the web site to indicate not chuffing.

(please verify, but I don't think there was any way it puffed smoke in sync)

And yes, you can INDEED make it puff, and the USAT one will work well, you just need to interface it properly and not overdrive the motor and heater:

Here's a video of that smoke unit, driven directly from a decoder:


you will have to experiment with the heater voltage...

read this page, I give the information on the heater voltage to use:

https://elmassian.com/index.php?option=com_content&view=article&id=168&Itemid=203

Now, your decoder cannot set a voltage, it sets output by PWM, so you will have to experiment with your PWM settings to get the equivalent of the voltage I recommend.

UNDER NO CIRCUMSTANCES SHOULD YOU EXCEED 5 volts to the fan, and about 9 volts to the heater... you will no longer use that circuit board, you will go directly to the smoke unit's 2 connectors.

This is done all the time here in the states, although we normally use Zimo and QSI, due to the better US sound libraries.

Greg
 
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Thanks for all the input, I am thinking about using the smoke switch on the loco to switch the regulator PCB on/off from track voltage, in this case DCC, have the fan disconnected and pulse this from the output of the Massoth decoder pulse string. The timing & output value can be set so I am hoping that by controlling via the smoke switch and pulse the fan I am going to be in business. I will let you know the results when action next week.

Re original pulsed smoke I am not sure as my track was not fully completed and I was also modifying the loco - hey ho!
 
Problem is that the smoker with heater and fan running draws approx 1 to 1,2 amps, according to my bench power supply. The decoder auxiliary outputs are rated individually at 600 mA even though the motor current is rated 6 amp and peak 10 amp. So really need track voltage to drive the heaters - however I will revisit this next week, if the heaters are less then 600 mA on their own then it would be a solution.
 
I thought the decoder had at least one high current output?

No, you are correct in budgeting an amp for the heater (there's only one element).. so a relay to turn it on and off, and I would suggest trying 9 volts max, i.e. not using the regulator board at all. You could find one of those cheap DC to DC converters that are adjustable, and then you can dial the system in... it's important you can do that if you run over the stock voltage to the heater.

At the stock voltage, the heater is pretty anemic, i.e. this whole thing is pretty worthless unless you up the voltage to get reasonable smoke.

Greg
 
The XXL decoder has a combined auxiliary output of a max 2.0 amp however individually the max is 600 mA each. Nonetheless have been able to run it reasonably successfully using an extra reed, switched by the rear driver, axle magnets, to pulse the fan and the regulator to drive the heaters. Still some experimentation to do but in principle have a usable system.

Thanks for all the help guys - I am now putting this thread on the back burner.
 
Interesting, normally that smoke unit fed from the regulator board did not draw quite an amp...

So, it's clear that the run of Hudsons you have one of is now using a different smoke unit than the original run... I wonder if USAT tweaked the regulator board to increase the current to the heater? I have had literally 50 of these smoke units go through my hands and the smoke output was always anemic, and that was because they did not run a lot of current through the heater, safety so they don't burn up. (I have a number of different USAT diesels)

If you have the fan going most of the time AND you use higher voltage/current to the heater AND you do not run it dry, it will smoke like my video and last a while.

So, the current you indicate from your bench supply may be telling... they may have tweaked the regulator board over what is in their diesels.

Looking at their site again, the synchronized chuff is no longer on the web site description, just a smoke unit...

BUT, in the manual:

SMOKE GENERATOR
The locomotive is equipped with a Sync-Ro-nized fan driven smoke
generator that produces steam exhaust synchronized to the axle rotation
of the driving wheels (four puffs per axle rotation). The smoke generator
requires periodic addition of smoke fluid in order to operate properly. To
add smoke fluid, add approximately 20 drops of USA Trains
smoke fluid(part number R50001) into the smoke stack. Remember less is better.
​
Have you located the chuff "switch" wire yet?

Greg
 
Most fan driven smoke units I've retrofitted the fan motor is usually always 5VDC and most of the stock heating elements were also rated at 5V, so when I hacked off the electronics, I used a full wave diode bridge and an LM7805 5VDC output regulator to the fan motor.

However, I also removed the 5V heater element{s} and soldered in new higher voltage {18V} units and ran the heaters directly off track voltage and get tons of smoke.

I tried using a magnet/reed switch to "pulse" the fan, but the pulses didn't last long enough to do much of anything, so I gave up on trying to puff the smoke using that combo.

Even tried using an extra magnet or two, but the puff just didn't work very well, if at all, mostly I either had no puff at all {fan motor more off than on} or I got a steady stream of smoke like the diesels {fan motor always on}.

Never could find a happy medium to make it work directly{puff smoke} from track voltage which is what I use to run and operate my trains.
 
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