# 24 volt DCS and 12 volt motors didn't work



## machiningfool (Nov 15, 2008)

The idea that I had to run two motors in series did not work, they ran erratically. I went back to the parallel configuration and they worked as normal. This is a follow up to a previous post. Robert Brown.


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## Greg Elmassian (Jan 3, 2008)

Next time, it's best to just add to the original thread... I just replied there.

Multiple threads on the same subject makes it impossible to follow progress.

Greg


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## machiningfool (Nov 15, 2008)

I made a new post so that everyone would see it up front. I didn't want them to start a procedure that was a disaster. Does that make sense? Robert Brown.


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## Scottychaos (Jan 2, 2008)

machiningfool said:


> I made a new post so that everyone would see it up front. I didn't want them to start a procedure that was a disaster. Does that make sense? Robert Brown.


No, it doesnt. 
still better to make your reply in the original thread, and not start a new one..
when you reply to an old thread, it becomes "active" and rises to the top again..people will be just as likely to see it as they would if you started a new thread, and having all the info in one thread is SO much better for clarity..

Scot


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## Garratt (Sep 15, 2012)

So..... where is the original thread guys?

Andrew

Here it is:

http://forums.mylargescale.com/29-beginner-s-forum/31033-24-volt-dcs-12-volt-motors-2.html


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## machiningfool (Nov 15, 2008)

*12 volt motors in series did not work*

OK, OK, I put it in the original thread, I am sorry I stepped out of line, just wanted to correct a fatal error, sorry about that, didn't know that this forum was so rigid. Well I am going to get back to building some models, I hope this little exchange is over. Robert Brown.


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## chuck n (Jan 2, 2008)

Robert,

It is not that we are rigid, but why should I answer a question in thread "B" when someone has given a similar or better answer in thread "A". It just adds more confusion and it is easier for everyone to follow the discussion, if it is all in one thread. From original question to final solution.

I think you now have three similar titled threads.

Chuck


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## machiningfool (Nov 15, 2008)

The more places they see my mistakes, the more often I save them for making the same mistake that I made. The number of posts that you made correcting me, took up way more space than if you had left me alone. Let me make a suggestion, why don't you spend more time building trains and less time policing peoples posts. I am here trying to help people, you didn't help me a bit. Robert Brown


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## Gary Armitstead (Jan 2, 2008)

Hey Chuck,

I agree with what you are saying to Robert. But just let it go. Not worth your time to try and help these folks. He is not the first one here lately that asks for help or suggestions and then "shoots the messenger" because they don't want to hear the message. This reaction from Robert is why I stay away from this site now. Not worth the aggravation.


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## SD90WLMT (Feb 16, 2010)

Thanks Gary...

I also dissagree with the lack of scientific approach to solving a problem...
One does not jump to conclusions based on NO-LOAD data..
Put the wheels on the track where they belong..run the motors in series....
They will work together better..same as a model airplane. In the air multiple motors in series come into sync...under load...after the speed is stable...no load on the ground..or locos spinning wheels ..accomplishes anything....

Make it work....

My 2cents also..." one thread" ...sorry ....but !!
Dirk


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## Homo Habilis (Jul 29, 2011)

Here is a reasonable summary of Good Forum Etiquette.

I try to follow it in spirit, but on occasion I fail.


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## machiningfool (Nov 15, 2008)

You are right, I did not put them on the track with a load. Am I correct that running the 12 volt motors with 24 volts with a TIU and MTH speed control that over speeding or over voltage won't be a problem? I don't know, that is why I am asking you. Robert Brown.


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## machiningfool (Nov 15, 2008)

Thank you ****, I will try to adhere to your suggestions, they make sense, Robert Brown.


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## SD90WLMT (Feb 16, 2010)

Great..now that your listening to those that have a great desire to "Help You"...

Getting down to brass tacks...I'm not qualified to comment on TIU or MTH components....

Your question surrounds an age old theory..one that has been well proven..
Voltage dividers do work...
Using two resistors in series across a given voltage input will divide that voltage by two..this is how early power supplies were created for TV's ..etc. unless they used tapped transformers to derive the needed power supplies..
Your two motors are nothing more than matched resistors ....

So it's time to be practical....find a stretch of track you can run on.. set the loco on the track...mark each wheel with a line at 12 O'clock....
You do need room to run ...10' - 50' long..
You need to be able to measure the applied voltage to the loco..advance to 6 volts...
You need to be able to measure at least one motor..which should be 3 volts.. both would be better..
Run the loco as far as you can...
Record the voltages...
After..notice the wheel lines...
...do they still match...yes or no...!
Dont worry if not...
Run this same process several times to obtain a trend or average results...
Then think about what has and is occuring..
Then draw a conclusion....

Now you will have some practical results to know what is occuring with your approach to a problem..before your wandering down the road..
Have fun with this...it is straight forward....
Let us know...

Dirk


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## machiningfool (Nov 15, 2008)

I appreciate your approach, sounds like you know what you are talking about. It is running in parallel right now because I didn't think to put a load on them after seeing the one motor just sit and the other speeding up, I didn't think that looked good, so I went back to parallel which seemed to run fine. Since you say you don't know about the dcs system, I guess you might not have any comments on my thinking. If I am correct, the TIU supplies 24 volts to the board and the board transmits the voltage to the motors. There is a speed control in the MTH system which I have adapted to the NWSL motor, I am thinking that this will save me from over voltage by not applying the full 24 volts, does that make any sense or am I still in the weeds? Robert Brown. By the way I have posted pictures of the E8 a and b and baggage car in model making. Robert Brown


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## SD90WLMT (Feb 16, 2010)

When one motor did not turn...it acted as a varible resistor...sure it did not run...maybe more resistance..maybe more internal friction... was stuck?
It may have had some voltage passing thru it..yet not turn..
The rest unfortunately went to the second motor....unloaded might be ok...

Why they will respond in a different manner on track...

Your cobbled system needs further testing....
The practical exercise above will help you sort this out ...
Just don't do anything under large loads or high voltages till you better come to terms with the results....
Current flow is always a function of demand...no demand = low current...whereas..high loads ( lots of cars or steep grades ) will generate higher amp draws ...

IF the MTH uses a speed control ( Esc ) you need to understand what it controls and sends to the motors...
If the TIA sends a pulsed width signal of 24 volts continously to the esc, you need to know what happens at this junction also....

Sounds like ...lots of back and forth to accomplish motor control..
Is this practical to do..?
Has anyone before you done this..?

Dirk - DMS Ry.


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## machiningfool (Nov 15, 2008)

Yes, it is common for MTH locos, but they are 24 volt motors, I suspect, the ones that I am using are NWSL 12v. You keep making good points. Just because the TIU gets 24 volts doesn't mean the motors are 24 volts. I am going to have to do some more work on understanding the MTH system, thanks. Robert Brown.


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## Totalwrecker (Feb 26, 2009)

machiningfool said:


> I made a new post so that everyone would see it up front. I didn't want them to start a procedure that was a disaster. Does that make sense? Robert Brown.


 
In my years here you are the first to try this experiment.
You have strayed from the herd more than are leading it..... there are no 'THEM', just a lot of disjointed posts....

no cents either....

Have a great railroading day!

John


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## Greg Elmassian (Jan 3, 2008)

At the risk of you feeling ganged up on Robert, I think it does bear reinforcement, especially since you have sort of "resisted" a few times before:

No, bad decision and bad reasoning.

People can STILL find your original thread, and without proper "ending" you have actually made things WORSE, i.e. someone finds the original thread and then does exactly what you say you did not want to happen, to start a procedure that was a disaster.

So, you really have caused exactly what you tried to avoid.

Basically, very bad form to not add to the original thread, especially when you originate the thread.

OK, don't feel hit upon, but this site can be valuable information, or a nightmare of disjointed information that makes it much less valuable to people looking for help.

Regards, Greg


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## machiningfool (Nov 15, 2008)

*Greg*

I thought this was over. The only one it seems that is worried about where I post is you. All I have done in the last posts have been answers to other peoples posts, wherever that might be. I understand what you are saying and I will, in the future post one topic at a time. I personally think that people should pay more attention to building trains than worrying about what other people are doing, and this is the last time that I will react to your posts. Robert Brown


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## Greg Elmassian (Jan 3, 2008)

The site is meant to be sharing information, thus we ARE INDEED paying more attention to building trains, to make the information better and easier to find.

Greg


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## jjwtrainman (Mar 11, 2011)

I'm only going to say this:

While what Robert did was not proper, it certainly doesn't the excuse the constant badgering in about 2/3rds of the posts on this particular thread (from several people by the way, not just one). Robert made a mistake, he said he won't do it again, what else is there to discuss? I'm not going to butt into personal feuds between individuals, but from someone outside the conversation this thread is riddled with comments from people who don't seem to grasp the concept of forgive and forget. 

Robert, I suggest just letting this thread go. Get back to the original thread and continue posting there. I'll be happy to follow the conversation from there.

As for everyone else, can we please just let this issue go? We've all got better things to do with our days than criticize others for minor mistakes. The only thing that makes a forum better is forgiving and forgetting, not by following a mistake with 3 pages of criticism.

As I said, I'm going to leave the conversation there. In the meantime, I'll be enjoying other threads which actually contribute to the forum in a positive way.

--James


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## SD90WLMT (Feb 16, 2010)

So staying up to date here...
The current solution is running the motors in a parallel affair...untill that no longer works well..or the motors become damaged ...

D


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## Greg Elmassian (Jan 3, 2008)

Not constant badgering... actually answering questions... if you ask "hey is this good or bad" and you cannot handle the answer, don't ask.

Back to the motors, we all hope the 12 volt motors won't be damaged by the 24 volt electronics... no one wants his motors to melt down.

Also, in the spirit of trying to understand what is happening, are the NWSL motors equipped with a tachometer strip and sensor as the MTH locos are?

Greg


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## machiningfool (Nov 15, 2008)

It is all MTH electronics including the speed sensor. I printed a new striped decal and put it on the NWSL flywheel, and relocated the sensor. I reduced the number of spaces, from 48, 24 white and 24 black, to 20, 10 white and 10 black, because the MTH gear ratio is 10:1 and the NWSL gear ratio is 25:1. Also the wheel size had to be taken into account. F7 has 40" scale wheels and the E8 has 36" scale wheels, so adjusting for both of those variables hence the lesser stripes.


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## Greg Elmassian (Jan 3, 2008)

I'm interested in why your results don't seem to match what most of us predicted.

To be clear, I want to understand, and since I do give a lot of advice, I don't want to give bad advice. So I appreciate you responding to these questions.

So I have gotten a bit confused, the loco that has this "series / parallel" issue, is it the F7 or the E8? I'd also like to know/verify:

1. only one motor per truck, right?
2. both trucks powered?
3. all powered trucks have a tach strip, or is it only one tach per loco?

Many of the MTH installs I've seen internally were steamers, so most only one motor.

Thanks, Greg


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## machiningfool (Nov 15, 2008)

The loco is an E8, MTH electronics, onboard TIU, battery powered, one motor per truck, both are powered, only one truck has a tach strip, NWSL trucks. The reason I mentioned the F7 is that the original electronics was taken from an MTH F7, different gearing and different wheels. An allowance, "fewer stripes", had to be rendered for the difference of gearing and wheel size, to get a ballpark register of speed. After tonight, I won't be able to answer posts for a month, my brother had a stroke and I am going to Arizona to stay with him. Robert Brown.


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## Greg Elmassian (Jan 3, 2008)

Very sorry to hear about your brother, I hope he recovers quickly, my dad just had one recently and it can be tough.

Thanks for the info on the trains, will chat when you get back.

Regards, Greg


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## machiningfool (Nov 15, 2008)

*Speed sensor explanation*

I am back and thanks for your concern about my brother, the operation was a success and now he has a long road to recovery through therapy. As to the explanation of the number of stripes reduction on the flywheel to get the correct mph speed. Assume that the original MTH motor that is 10 to one gearing, at a speed register of 40 mph, with 48 spaces on the flywheel was changed to the 25 to one gearing and the power to the motor did not change. The speed in mph would still read 40 mph, but the lower gears would slow the actual speed of the loco to say around 12 mph. In this condition, the only way to match the speed in mph would to reduce the number of spaces or stripes on the flywheel to 20 spaces, 10 white and 10 black. This way the readout of mph is reduced to match the lower gear. You said there are some people that do not agree with my explanation, so I would like to hear the argument that they have where they disagree or agree. Now the actual number of stripes mathematically came out to be around 18.7, but I chose 20, because it was easier. Robert Brown---- Since I gave this explanation, I have tested further as explained in the threads to follow on the 4th page, but to more closely link what I did, here it is. To get a more exact reading on the speedometer, I further reduced the stripes to 8 white and 8 black and the result was almost right on. With a 34 foot section of track at 40 mph scale speed the loco should move at 1.833 feet per sec. Divide that into 34 feet and it comes to 18.5 seconds, in a test it timed out to 18 seconds, so the number of stripes is as close as I can get without changing the diameter of the flywheel, and I am not going to do that. The actual scale speed is probably 41 mph. so that is close enough for me, because I don't plan to lash up. I will probably run at half speed, around 50, so I doubt if the voltage difference will be a factor, if it does, I will let you know. NWSL is thinking about producing 24 volt motors possibly, so that will solve any problems that I may have. Robert Brown.


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## Greg Elmassian (Jan 3, 2008)

As far as I know, you correctly compensated for the change in gear ratio, exactly as you have explained.

Bear in mind that wheel diameter also needs to be factored in. Are the original wheels and the wheels on the new motor block the same diameter?

The tachometer drive is a nice feature of MTH, it allows for precise calibration of speed, such that different locos will all run at the same physical speed for the same throttle setting.

Greg


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## machiningfool (Nov 15, 2008)

*Correct number of stripes for MTH/NWSL trucks sensor*

I set up a test for the speed sensor in My E8, and here is what I found out. I had to reduce the number of stripes wrapped around the flywheel to 8 white and 8 black. It read correctly at 40 scale mph. Here is how I did it. At 40 mph readout, the loco. travels at 1.833 ft. per sec. My track circle is 34 feet, so it should take 18.5 seconds to travel that distance. It took 18 seconds, so the real speed is around 41 scaled mph, but that is as close as I can get. This test was for MTH electronics, NWSL 3 axle truck, 1:32., So there you go. Robert Brown


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## Greg Elmassian (Jan 3, 2008)

I'd say that was **** good... very few people other than Raymond Manley venture that far (and succeed).

Regards, Greg


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## machiningfool (Nov 15, 2008)

*MTH one gauge motors are 12 Volt not 24 volt.*

After all of this worry about MTH electronics applying 24 volts to the locomotive motors, was unnecessary. The supply to the TIU is 24 volts, but the processor in the loco, supplies 0 to 12 volts depending on the speed that you desire, so my NWSL motors are completely compatible with the MTH power. This info. was obtained from an MTH tech. named Jeffery, he gave me permission to use his name. After all of this discussion about the voltage applied variably or sustained it turns out that that voltage is variable controlled by the speed controller, 0 to 12, in the loco. Robert Brown.


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## Torby (Jan 2, 2008)

Overvoltage to your train motors will not be a problem. Here's why:

You regulate the speed of the loco by varying the voltage to the motors. If your loco contains 12v motors, when you dial up the voltage to 12, the train will be running REAL FAST, so you won't exceed the designed voltage anyhow.

Ok, you can take this to extreme and try to run it on pulses so high as to arc the commutator and destroy the motor with 4KV pulses though the average voltage is 9, but with any reasonable train equipment, that's not going to happen.


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## machiningfool (Nov 15, 2008)

OK, originally the consensus was that MTH had 24 volt motors in their locos, that is not the case. The motors are 12 volt just like my NWSL motors, so you are correct, there is not a problem.


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## Greg Elmassian (Jan 3, 2008)

Well, I doubt that the motors get 0-12 volts, but they are pulse width modulated with full track voltage minus about a volt or 2.

I'd have to get someone to put a scope on the motor outputs. 

Having analog DC voltage control takes BIG transistors and BIG heat sinks, neither of which I see on the MTH circuit board.

Many people put a volt meter on the output, and the meter averages the pulses, just like the motors do. They will swear that it is 0 to 12 volts all the way to the grave.

The definitive answer is a scope on the motor output.

The motors may indeed be 12 volt, and capable of handling the 24 volt pulses, but at full speed they should get track voltage.

I'd like Jeffery to tell me that there is a 12 volt regulator or limiter in the MTH decoder electronics... and that it is NOT a pulse width modulated circuit... ask him these questions.

read this thread, Ted Hikel states that the MTH motor drive system is PWM, which means variable pulses of FULL track voltage.

Greg


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## machiningfool (Nov 15, 2008)

Well, I did just that last night. At around 60 mph, my volt meter was reading 12 volts and the motors sounded like they were going to explode. The loco was a stock F3 one gauge. I don't think that they are supposed to go faster than 60. Thanks for your input Greg.


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## Greg Elmassian (Jan 3, 2008)

No problem, as I said, the motor and your voltmeter will average those full track voltage pulses to something lower.

Many times the motors can handle it... in early times some manufacturers warned against "pulse power", but more recently manufacturers have put integral fans and cooling slots in the motors to shed heat.

A lot of motors are essentially 18v motors and seem to work ok.

Regards, Greg


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## machiningfool (Nov 15, 2008)

Thanks again for your knowledge. I know now that at 60 mph it will be putting out 12volts, so that is as high that I would run my loco anyway. Robert Brown.


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## Greg Elmassian (Jan 3, 2008)

One last tip, if you can touch the motor after a "hard run" you can basically tell if you are working it too hard.

Harbor Freight also has those "temperature guns" for cheap on sale, so you can test without grabbing and picking up the loco.

http://www.harborfreight.com/infrared-thermometer-93984.html

Basically, motors are damaged if they heat up so much that the insulation on the motor windings fails, it's a very thin enamel coating, and if it melts, then the adjacent coils short, altering the characteristics of the motor, drawing more current, making it less efficient and creating in turn more heat. Turns into a vicious cycle. There are other failure modes, but this is the primary one.

Regards, Greg


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## machiningfool (Nov 15, 2008)

With ProtoSound is there anyway to get amp or voltage feedback?


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## Greg Elmassian (Jan 3, 2008)

I don't believe so, have not seen it mentioned, but I am not a DCS expert.

Greg


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