# My Beginner Track Power



## Cosmos (Apr 16, 2011)

My Beginner Track Power
Thanks to many people on here, a lot of reading, and a lot of searching I learned about DC track power and wanted to share my experiences.



My layout is approximately a ten by twelve foot oval of brass European style Aristocraft track on a flat concrete patio. Neither of my two 1amp Bachmann starter transformers would reliably power this small oval with a single Bachmann Thomas the Tank Engine set pulling two to four cars. The train would stop, and I would have to allow the Bachmann transformer to cool down before the engine would run again. Additionally running more than one engine would reduce speeds to a crawl and cause the power supply to shut down even faster. 


As a result of a lot of research and some advice from this forum I purchased an 18v 10amp regulated switching power supply and a 30amp 12v Pulse Width Modulation board. I chose the 30amp PWM board so I don’t have to worry about over heating the PWM board ever, it was less than five dollars more, and if I want to upgrade later I only need to size up the power supply. After purchase and assembly I wired them up to the track in a single block (single block means only 1 point of connection on the track). So far everything works FLAWLESSLY! My Bachmann trains run, smoke on my Bachmann trains work great, my LGB trains run. Not only do they all run it is really cool watching the trains run at crawl speeds with the PWM board offering the torque to go slow though pulsing the full 18v to the motors. I can pull 7-10 cars now without a single issue. And if my son wants to see more than one train running on the oval it isn’t a problem, I have linked up to 3 trains at once. I will get back to you guys with results on the Bachmann sound as soon as I can, the Circus train hasn’t been in as high demand as the Thomas trains.


As far as track cleaning goes, the absolute best thing I have tried as of yet and haven’t seen posted on here are gun cleaning patches. I purchased an inexpensive patch and cleaner combination and it takes about 2-3 patches to clean the entire loop and the brass really shines. It is safe for plastics since many guns are polymer now days (make certain the cleaner IS safe for plastics first!) and the dirt and gunk it pulls off the track is amazing. Not to mention it is fairly inexpensive, a few bucks for ~200 patches soaked in solution.


Future upgrades include a reverse polarity switch a nice project box to contain everything and more track, loops, switches, and bridges.


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## Jerry McColgan (Feb 8, 2008)

Hi Cosmos,

Nice write up. You have an approach that I find interesting. 

As a fellow track power guy I would like to hear more about your "30amp 12v Pulse Width Modulation board."

While some manufacturers have used Pulse Width you are the first individual I am aware of who had added it independently to his layout. I would like to hear more about why you did it, how you wired it and what your results have been.

You mentioned "18v 10amp regulated switching power supply and a 30amp 12v Pulse Width Modulation board." I am curious about the 18 volt power supply and the 12 volt PWM board. I am not being critical - just curious.

As a fellow shooter as well, I find your use of gun cleaning patches additionally interesting. How are you using the patches to clean your track (are you using them manually or attaching them to something)?

I am also curious how you come by the alias "Cosmos" (I am a curious guy).

I suspect we will be hearing more interesting ideas from you.

Jerry


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## Cosmos (Apr 16, 2011)

Jerry, 

I would love to answer your questions about Pulse Width Modulation. It was a VERY easy build. I purchased a power supply kit and a PWM kit, assembled them independently, supplied the PWM board with power from the power supply, and then supplied the track with the signal from the PWM board. All control is through the PWM kit. I have a constant 18v supplied to the PWM board. 

Voltage isn’t a huge concern at these levels especially with the 30a capable board. If it was a lower amp board rated at 12v for the PWM and I was driving it to 18v and matching the rated amperage we would be teetering in the zone of burning things up. However I doubt my small setup will ever see 10a, much less the 30a the PWM board is capable of supporting. In other words 18v at 10a isn’t going to stress a board designed for 12v and 30a. I will keep you guys up to date on how things work long term, but as of right now we are not having any problems and we are running it 3-5 times a week for about 2 hour at a time. I haven’t measured the amperage draw as of yet but I have no problem driving 3 Bachmann Thomas engines around the track the entire time pulling all of the Thomas and Friends rolling stock we own. 

I just take the patches and run them over the track by hand. It takes less than 2 minutes to do, and the brass looks brand new on the conduction surfaces, and with my track being shaded by a pine tree this it gets dirty very quickly. 

I’m a fan of Carl Sagan and his television show Cosmos.


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## krs (Feb 29, 2008)

In other words 18v at 10a isn’t going to stress a board designed for 12v and 30a. 

You're thinking of "power" but that's only part of what you need to be concerned about. 

Could you post a link to the PWM kit that you're using.


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## Cosmos (Apr 16, 2011)

krs, I have been searching, but can't seem to find the box/info. I'll keep looking. It wasn't anything special, just a small board with very few components.


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## Cosmos (Apr 16, 2011)

Just an update. Everything is still running great. We have 20+ hours on this since my last update. As promised, an update on sound ... my Bachman Brothers Circus train has perfectly working sound. As the train slows so does the sound of the train. 

Also, I found out that chlorine free baby wipes do a good job of cleaning track. No where near as good as gun cleaning patches, but it's not bad.


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## Cosmos (Apr 16, 2011)

KRS the PWM Board is made by Maxx Tronic. It is a version of the MXA066 DC Motor Speed control 30 Amp. It says it is for use with 12/24VDC 30a Max.


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## Bj702 (Feb 26, 2011)

thanks for the info, i'm liking what youre saying. as i'm electronics basic knowledge is it possible for you to post a wiring diagram of your setup? thanks


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## krs (Feb 29, 2008)

Posted By Cosmos on 05 Jul 2011 04:23 PM 
KRS the PWM Board is made by Maxx Tronic. It is a version of the MXA066 DC Motor Speed control 30 Amp. It says it is for use with 12/24VDC 30a Max. 
Thanks Cosmos,

All I could find on it was this short description below.
I would have preferred a schematic, but the only one that came up was a You Tube video which was a bit awkward to look at since one couldn't see the whole schematic at once.

Anyway - from this description:

The MXA066 is a small assembled device with an on-board trim pot to control the pulse width modulator output. Keep in mind that you should determine how hot the unit gets. If it gets to hot it will fail, in order to be able to carry high amperage for extended periods of time you will need to provide additional cooling. The unit will carry up to 30 amps but not for long periods of time. Use common sense when powering large loads.

This has been a very popular module for Hydrogen Fuel cells. Use this module to regulate the amount of current going into your Hydrogen fuel cell to prevent overheating.


Power Supply: 12/24VDC Load Voltage: 12/24VDC 30 AMPS Max. Motor Speed: Uses PWM principle for motor speed control. Output Frequency: 100 Hz Motor Speed Adjustable from 0  100% PCB Dimensions: 3.85 x 1.59


CONNECTING AND OTHER SPECIFICATIONS


POINT + 12 V is connected to the positive pole of the power supply 12VDC


POINT + M is connected to the positive pole of DC Motor.


POINT  M is connected to the negative pole of the DC Motor.


POINT G is to be connected to the negative pole of the power supply.


VR 10K is used to adjust the speed of the DC Motor


J is used to select the power supply 12v or 24VDC for the DC Motor.

I assume you have the unit set for 24 volts.

The only thing I don't like is the very low PWM frequency of 100 Hz.
That tends to heat up the motors in the locos.

Also, the 30 amp rating is driving a 12 volt motor and adding additional cooling.
You're driving a higher voltage which means the unit can provide less current, but for trains it's still plenty.

Knut


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## Cosmos (Apr 16, 2011)

It is quite simple. 
The power supply has a cord supplying power and ground from the wall. 
There is power and ground from the power supply to the pulse width modulation board.
There is power and ground from the Pulse width modulation board to the track.


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## Cosmos (Apr 16, 2011)

It doesnt' have any sort of set up for 12v or 24v. Just put it together and wire it up.
I haven't had any motor heating issues in the locomotives, but I'm not pulling huge loads and I'm on a small flat track. On average the train(s) is(are) running ~2 hours a night several nights a week. They also have adjustable frequency PWM modules I just don't believe the additional funds were necessary for model railroading. From what I understand the frequency is more of an audio issue than a motor issue. At least that is what the engineers I work with tell me. They also mentioned 100Hz isn't going to affect train audio, it is more of a high-fidelity issue. I'll try loading down the trains with a brick and I'll see how the motors do with heat and load.


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## krs (Feb 29, 2008)

Cosmos, 

There is a jumper "J" on the board itself where you select between 12 and 24 volts. 
I don't know which setting is which but that should be in the instructions that came with the unit. 

The effect of motor heating using PWM depends on the motor, basically how well the motor can dissipate the heat. 
The motors in the locos we use are DC motors really designed to be used with a DC voltage. You are driving it with 100 cycle pulses - so yeah, you get the noise problem which is just annoying, but the motors also heat up more. 
All DCC decoders today use PWM to drive the train DC motors but none of them (at least I think) still use low frequency PWM; even the last version of the Aristo TEused around 12000 cycles or so, DCC decoders tend to use 16000 cycles and up. 
At those frequencies the drive signal looks more like a DC signal to the decoder. 
Anyway - I'm not saying that you necessaily have a problem - all depends on the specific motor design used. Just something you may want to keep an eye on with every new engine.


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## Cosmos (Apr 16, 2011)

Everything is still running quite well. We have a TON of hours on this railway now and the kids still love it. I can't wait for some snow!


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## Cosmos (Apr 16, 2011)

Still running great with about an hour a day on this setup.


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## vsmith (Jan 2, 2008)

Just a quick observation, those Bmann starter power packs are only 1/2 amp. They are only good for the small starter track loop. My old layout at 8' x 20' and my current 12' x 8' spaghetti bowl track plan use a single LGB amp pack with no issues. Sell those crappy Bmann units on Ebay, some small scaler will put them to use.


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## FiatFan (Feb 12, 2013)

I've been looking at the MXA066 for some time now. My question is whether you have any kind of circuit breaker built into the assembly. If so, what size/type do you use? 

Tom


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## Cosmos (Apr 16, 2011)

Posted By FiatFan on 16 Feb 2013 07:36 AM 
I've been looking at the MXA066 for some time now. My question is whether you have any kind of circuit breaker built into the assembly. If so, what size/type do you use? 

Tom 
Tom,

Sorry for the late reply (10 months), I'm fairly busy and don't get to spend as much time on the internet paging through forums as I would like. When I first wired this up I didn't have a breaker, however I now have a small breaker that I pulled out of an APC UPS; truthfully I don't remember what the breaker is rated. At the time I knew it was the appropriate sized unit for my setup, but I can't remember what it is right this minute. I'll try and remember to take a look at it this week and get back. Right now the transformer is running a 24 hr platform at my train club's holiday display. We are 4 days into the 24 hour operation and so far I hear everything is operating wonderfully. 

Also, everything fit into a small plastic Playmobil Carrying case. I believe this is what originally came in the case: http://www.playmobil.us/on/demandware.store/Sites-US-Site/en_US/Product-Show?pid=5956 

Everything is still running strong with tons of hours on the unit and the trains are still running great without any issues.


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## Cosmos (Apr 16, 2011)

Still running strong. Everything gets used almost daily. No issues with trains, sound, lights, etc.


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## Cosmos (Apr 16, 2011)

We moved and I made my oval a little bit larger and placed it inside a multi-season room. No more cleaning up pine needles off the track! YAY! Power supply is still going strong, and the kids are still putting a ton of hours on it.


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