Very High Amp Decoder

Are you pulling 4 amps from your power supply with just the motor ?

If not then a better heatsink on the output driver may help, or a fan.

A better motor might be cheaper than a higher amp decoder.

Maybe a booster amp between the decoder and motor.

How many volts are at the track? If the decoder can handle it I would try and raise the track voltage. What model of DCC controller are you using? Are there different settings for track voltage?

Some engines find the weaknesses of our layouts like power dipping in certain areas.

I'm not sure which company makes one.  But I did the math and 746 * 0.1 = 74.6 watts claimed for the motor.  At 12V, this works out to a little over 6 amps.  So if someone makes one, a 6-amp decoder MIGHT work.  A 10-amp decoder would be better.  Yes, re-motoring, using a motor with the same peak torque and a higher-voltage winding might be a valid approach.  If you can place the decoder in the tender, a G-scale decoder might work.  I would look at the product line-ups for companies like Zimo and Lenz. 

Wow, this engine must be a power hog!

Maybe you could see what the improvements were done, that are described in this video by a member here?

Dear Ed,

NCE 808-8 AMP Decoder. Hope that helps. John

You should be able to put 20 volts on the rails thus reducing the amp draw to 3.73 amps

Have you tested the motor and mechanism on just a 'dumb' DC power supply? That's a pretty massive current to be drawing if everything is operating well.

Here's an excerpt of a post I am working on for another decoder install, that describes a motor startup voltage and current draw test I like to do. Might be of some help, just to make sure you've worked out any mechanical issues or inefficiencies.

Motor start voltage and no-load current

One of the first tests I do on an engine once I get it all stripped down is a motor startup voltage and no-load current test. This can give a really good indication of any fundamental motor, geartrain, or linkage issues. (This is actually really easy to do just about any time you have the shell off, and is a good preventive check.)

I do this test using a benchtop DC power supply. Starting with the lowest voltage setting, I slowly ramp up the voltage and look for the point at which the motor just starts to turn. For a typical motor installed in the locomotive, I normally see startup at around 0.8 to 1.0V and 0.2-0.3A. If the voltage is much higher than that, something probably needs attention. This is also a good time to let it run just barely ticking over and watch for any irregularity in the motor speed or wheel speed. Any slight increase in drag will cause the motor to stall. If this happens at a consistent location, it usually indicates an issue in the drivetrain.

The key aspect of this check is that, unlike with the decoder installed, the voltage here is not feedback controlled. With the decoder installed and running normally, it will try to drive through increased load by boosting the motor voltage. While the engine may operate, this can mask issues that can lead to long (or short!) term mechanical and electrical reliability problems.

Then I ramp up to about 5-7V and look at the current. The motor should be humming along at a pretty good mid-speed pace at this point. With just the drivetrain friction, current should be in the 0.1 to 0.2A range. This is a good time to watch and listen carefully for any noise, vibration or rattling, which can indicate wear in gears, lack of lubrication, or minor binding in linkages and so on.

I do these checks in both forward and reverse directions by reversing the polarity. If the forward and reverse direction voltages differ by more than a couple tenths, that's another indicator. If there are multiple motors, I test each motor individually and compare. Again, the values for both motors in both directions should be similar.

In the case of this engine, I was a bit appalled when I measured a starting voltage of over 2.5V and current of about 0.7A! Clearly something needed help, and it didn't take long to figure out - the old gearbox lubricant was completely congealed around all the gears. After a complete teardown, cleaning, and reassembly with proper lubricants, the starting voltage and current were right where they should be, and everything was running really smooth. Another example - when I did my Lionel docksider a while back, I discovered that the quartering on one axle was off by one spline on the shaft, because the motor was stalling out at a repeatable wheel position.

thor73 posted:

….With just the drivetrain friction, current should be in the 0.1 to 0.2A range. 

In the case of this engine, I was a bit appalled when I measured a starting voltage of over 2.5V and current of about 0.7A! 

so how big is this 4 amp draw then? Wow. I could see if there were multiple motors inside or with a smoke unit stuck on. If only one, this motor must be terrible? Is there binding or wheels out of quarter? Poor gearing? Just wow.

When you run in conventional, I believe the draw is higher than in command? Most decoders that I've installed, tame down the amp draws and the motors behave much better.

jdunn posted:

Dear Ed,

NCE 808-8 AMP Decoder. Hope that helps. John

They make great decoders that you could use to control the motor and add the Tsunami for sound and extra lights.

I wonder if the decoder is actually shutting down from excessive heat build up instead of over or high current? I don't think some brands can dissipate the heat that's built up.

 So maybe a fan inside with extra heat sinking might help. I've seen posts about certain brands overheating when the current is near their capacity. I didn't like having to daisy chain different brands of decoders and struggle to program them for precise motor control. Others crack on my choice, but it's a major part of why I went with MTH. They handle the motor current very well. The sounds are close to the original. You may have to manually play with the sounds if you want engine over revs and etc. They also handle smoke units and lights very well. At the time, they were the best game in town for me. I'm still happy with them overall.

Hi All,

Thanks for the suggestions.

A little more information:

This is an O Scale engine and not an S Scale engine as shown in the video.  Matt Forsyth did that work and he is a superb craftsman.

The motor is a Pittman 13000 series motor and can draw as much as 30 amps if memory serves.  I have no idea why Overland would put such a massive motor in any engine.  My only thought is that it was done for advertising purposes.

My DCC system works well.  This is the only engine with this problem and I am not about to change the system dynamics for this one engine.  The engine will have to be adapted to the system.  The track voltage is about 16 volts.  Changing the decoder is easier than changing the motor but changing the motor is still a possibility.  The engine has just been cleaned and lubed so no problem there.  This engine ran well on DC and at much lower amps.  I can't explain the difference.  

I will print this discussion and use this information to determine my next step.

Again, thanks to all.

Ed

The amperage listing is because it is a servo, maybe a stepper motor, so it not really intended for a constant draw like a normal motor. But being a servo motor is about all I could find on it. I don't know what effect different frequencies might have on it, but it seems to me it likely could be effected by the pulses unless it can be tricked into thinking it is a normal motor....?

Adriatic,

It is not a stepper motor.  It is a normal motor, just a really large one.

Ed

By my research, Pittman never made a "13000-series" motor.  They did make a 14000-series motor (which is one size larger in diameter than the 9000-series widely used by Lionel and MTH from 1995-2010.)

There are variations of the 14000-series motor that have a stall current of 30 amps.  As expected, variations with a higher-voltage winding have a lower peak current.  It's hard to believe that a model train manufacturer would design and sell a loco that exceeds the capacity of most power packs in operation.

I guess what the original poster needs to do, is to see how much current his loco actually draws pulling a heavy load.  It might turn out that it's necessary to install a smaller motor, or higher-voltage motor to bring this loco's current consumption below the threshold of modern DCC decoders.

 USA Trains diesel engines used to be said that they were power hogs. I believe that came from running them on straight DC with too small of power supplies ( from smaller scales). As I got deeper into G scale, I wondered how the Aristo Dash 9 engines used 4 motors that appeared to be like the 2 that are in the USA Trains diesels. As I learned more about G scale and getting enough power to the track, new decoders kept coming out that claimed to handle higher amps.

 I met a man named Ray Manley (online), and asked him how the MTH decoders handled the higher draws like the USA Trains were said to have. I remember he seemed surprised by my question and said they will handle them very well. Years later I realized that the USA Trains, and other brands, run normally under command with actually low power draw. I was told you couldn't run very many engines unless you had really big power.

 I say all this because way back, I had one USA Trains SD40-2 that did not get run. It seemed to be a power hog and I had many MTH models that ran under command. So this engine sat there until I had it upgraded to MTH command. The engine had many other issues but it served as a tool to teach me about power on my growing layout. If it ran good, every other engine I had would be fine. So it became my standard to set acceptable power throughout the layout.

 To this day I find every topic about power distribution very interesting and I read every engine issue that pops up. I try and apply what I've learned, and stay open minded about learning new things too. I find that putting power on a much bigger layout in G scale, is no harder than doing it in O.

Anyways this is the only reason I chimed into this post. I don't have the OP's engine and have never worked on them. I do my own installs on many brands in different scales and try to learn all I can.

Ed Kelly posted:

Adriatic,

It is not a stepper motor.  It is a normal motor, just a really large one.

Ed

This made me look at my source closer.   Another boolean failure, criteria thrown aside by "smart searches" and I missed it. The1300 is the servo, not 13000.  They must have needed another zero to make a decision 

Join me as write another lousy feedback to Bing and Google about it tonight. I'm tired of being "told" what I want to search for. You too?

Adriatic posted:

Ed Kelly posted:

Adriatic,

It is not a stepper motor.  It is a normal motor, just a really large one.

Ed

This made me look at my source closer.   Another boolean failure, criteria thrown aside by "smart searches" and I missed it. The1300 is the servo, not 13000.  They must have needed another zero to make a decision 

Join me as write another lousy feedback to Bing and Google about it tonight. I'm tired of being "told" what I want to search for. You too?

I swear that all the search engine on most of the sights I use have gone down hill. They used to be decent. Someone with high credentials probably got big bucks to redesign them? Maybe not. Maybe some kindergarten kids did it for a project?

 They are probably used to raise sales on whatever is available right now. My favorite is when it shows something completely different than what I'm searching for.

Ted S,

You are correct.  It is a 14000 and about 5 inches long.  I will have to take the engine apart and give it a close inspection, again, to try to find the problem.  I have a spare 9000 series that I could install and see what happens.  

Thanks,

Ed