Max Track Voltage

[Nucular]

I am currently using a DCS51 from Digitrax, and the rated track voltage is 13V. I was wondering what is the highest track voltage one can use for On30 Bachmann engines, before burning the engines out. I know that I should be able to go up to 15 Volts with a booster, as that is what HO uses, I am just not sure if I should have O gauge power of 20 Volts.

I mainly want more volts, as more volts should make the train go faster.

 

[Iron Horseman]

I am currently using a DCS51 from Digitrax, and the rated track voltage is 13V. I was wondering what is the highest track voltage one can use for On30 Bachmann engines, before burning the engines out. I know that I should be able to go up to 15 Volts with a booster, as that is what HO uses, I am just not sure if I should have O gauge power of 20 Volts.

I mainly want more volts, as more volts should make the train go faster.

Concerning electricity you should probably treat the On30 locomotives like an HO loco, but there should be specifications in the user manuals that state the max voltage.

Narrow scale locomotives are known for running slow. Even the real ones had top speeds of about 40 mph. The Durango and Silverton runs more like 25mph. I'm afraid if you want speed you have chosen the wrong trains to model. Steam locos that go fast are like the Hudsons and Northerns 90+mph on those.

 

[Nucular]

It is not so much the speed, I just wanted to make sure that I am not using some undersized train transformer. My Digitrax puts out 13 Volts. If I get one of their boosters and set it to HO, I will get 15 Volts of power. There is the potential that I am not using 2 Volts of extra power, which would be a solid 15% increase in train power. I figure why restrict my throttle range down. Why use an N scale transformer for an HO layout. What got me more confused and somewhat questioning of it, is how On30 is O gauge, yet it runs on HO track, so should power be treated as HO or O entered my mind.

Anyhow thanks for answering.

 

[Selector]

A booster should not back-feed toward its supplying device, but should only boost the signal and the voltage. I doubt that boosting the voltage would somehow corrupt the signal or impart more noise, although I am not an expert. In fact, when it boosts the signal into an even higher voltage, I would expect the signal-to-noise ratio to improve, not to degrade.

I have a Christmas train set that is Bachmann On30. I operate it with the HO DC power pack supplied by Bachmann with the train set. I have never measured its maximium DC output, but it it were less than 15 volts, I would be surprised. If you knew what kind of decoder this engine of yours has, you'd also be able to determine its maximum continuous operating amperage. Even so, if it is in a tight space under the boiler cover, it might get warm enough to begin to protest at only 1.6 volts continuous. Even so, are you really anticipating having to use all those supplied amps?

 

[Nucular]

I should clarify what I am doing, which should hopefully answer a few questions. Here goes:
1. I have a Digitrax Zypher DCS51 which has a rated output power of 13.8V. The train goes around slowly.
2. Digitrax allows for a booster to be used which not only will allow more amps for a particular power block, but also will allow me to select the scale of the train. It outputs 12V for N scale, 15V for HO scale, and 20V for O/G scale.
3. The DCS51 by Digitrax already is a throttle, and puts out 3 amps.
4. The engine only uses the power it needs. It will not draw more amps than needed. I could have 100 amps on the track and it would not effect the motor, the motor will still pull the amps it needs. How do I know this, because I work in the engineering department for a company that purchases motors to make pumps, and I have talked to motor vendors. Having a higher horsepower motor does not help you, if the load is low, as the motor is than oversized and it will only use what it needs, the other power is just being wasted.
5. Now volts on the other hand will increase the PRM of a DC motor. Having more volts will increase the speed, however having too many can cause the motor to overheat and damage.
6. I just ran a test between my DCC Digitrax DCS51 at full throttle which means the computer is telling the engine to use all 13.8V. It took the train 61 seconds to travel 44 feet of track. Next I disconnected the DCC transformer, and plugged in my 15VDC train transformer. At 15V the train only took 42 to 43 seconds to travel 44 feet.

So what does this all mean. A simple 1.2 Volt difference makes a train ~34.5% faster/more powerful. This means that the train can pull more cars and go up steeper grades.

In the end it means, that my ultimate plan is to purchase a Digitrax DB150 5 Amp DCC Command Station/Booster with Intelligent AutoReverse, and use it power the main line of the railroad. The DCS51 Zypher from Digitrax will either not be used to power the layout, or will be used on a switch yard, where higher speeds are not desirable, and slower speeds are preferred.

 

[Selector]

...
4. The engine only uses the power it needs. It will not draw more amps than needed. I could have 100 amps on the track and it would not effect the motor, the motor will still pull the amps it needs. How do I know this, because I work in the engineering department for a company that purchases motors to make pumps, and I have talked to motor vendors. Having a higher horsepower motor does not help you, if the load is low, as the motor is than oversized and it will only use what it needs, the other power is just being wasted.
5. Now volts on the other hand will increase the PRM of a DC motor. Having more volts will increase the speed, however having too many can cause the motor to overheat and damage.
6. I just ran a test between my DCC Digitrax DCS51 at full throttle which means the computer is telling the engine to use all 13.8V. It took the train 61 seconds to travel 44 feet of track. Next I disconnected the DCC transformer, and plugged in my 15VDC train transformer. At 15V the train only took 42 to 43 seconds to travel 44 feet.

So what does this all mean. A simple 1.2 Volt difference makes a train ~34.5% faster/more powerful. This means that the train can pull more cars and go up steeper grades.

...

True, a motor only draws amperage on the basis of load demand. However, as your amperage rises, and the volts stay constant, the motor will heat up....not because of the voltage but because the ratio of amps to voltage is too high. For a given amperage draw, as you raise the voltage the motor will want to cool somewhat initially. The motor does not get hot from voltage since voltage is not a measure of 'work'. Instead, amperage is directly related to work, and since a motor is not a perfect machine, and does not drive one further down the drivetrain, it will give off heat.

That said, as you raise the voltage, the motor will want to speed up. If you keep all other conditions to which you subject the motor equal, as you raise the voltage the motor will want to draw the amps it needs to effect the change of speed. This necessarily means heat buildup. Decoders are known to get hot. Some get too hot. Those that are poorly ventilated and placed in cramped spaces will be bathed in heat. Heat kills electronics. That is why your decoders should be able to take the maximum amperage possible and keep running because when they get involved in a short, and the system is a bit slow to detect it and shut down power to the rails, usually in milliseconds, the full rated amperage of the system will course through the decoder nearest the short. That is, in hard shorts, the decoder will get fried more quickly that is poorly designed and poorly ventilated.

The 13.8 volts you mention...that's lots for most locomotives in HO, whether DC or DCC, to move a decent consist at track speed, although it does vary with the condition and characteristics of the drivetrain and running gear. Agreed, even more voltage should help such a drivetrain to move along more smartly. However, decoders have Configuration Variables, or CV's, that govern every behaviour, one being its maximum voltage to the motor. That is commensurate with maximum speed, and is resident in CV5. CV6 is the mid-voltage setting for the throttle. If your current setting for CV5 is only allowing 13.8 volts to get to the motor, maybe that is actually a limiting factor for that particular motor, as slow as it unfortunately is. It might be worth doing a factory reset of the decoder and then seeing how fast it moves at max throttle. If it is the same, and gearing is not especially low in it, then I guess something else must be going on..a dud motor? If it moves about as quickly as it did when you measured its performance during DC testing, then you have your answer...CV5 was set low.

BTW, you can get the more powerful 5 amp system, which is the same as the one I use. However, no one HO decoder is ever going to use more than 2 amps. When it does, it will be drawing its maximum rated draw, and you can expect it to perform impressively if for a short period of time. I would expect it to shut itself down thermally within a minute or two at most, and that's only if it is working well as per design. One of the tests for a decoder is to hold it down onto the rails with just enough force to allow the wheels to spin slowly at max throttle and use a ramp meter to see what amperage is running. Most HO decoders are at or just under 2 amps.

 

[Mark R.]

So what does this all mean. A simple 1.2 Volt difference makes a train ~34.5% faster/more powerful. This means that the train can pull more cars and go up steeper grades.

The 1.2 volt difference will make it faster, but it does not make it more powerful .... you are just getting a faster run at the grade ! All motors, regardless what size have a torque / HP rating (you should know this). Even the little motors in our train engines, although you would be hard pressed to actually find the specs, but they do have limitations. Then there is also how the motor's specs translate through the drive and to the wheels. This includes gearing and weight of the engine. Same as in a car - the engine horsepower is not the same as the horsepower measured at the rear wheels.

For example - load up a bunch of train cars to the point where your engine won't pull them at 13.2 volts. You could give it TEN more volts and it still won't pull them. That being said, there are other factors at play .... at the point your engine could no longer pull the cars, are the wheels spinning or is it stalled ? If it is stalled, you have exceeded the torque capability of the motor and its related gearing. In a stalled condition, adding more voltage will just raise the current draw and potentially damage the motor and / or the decoder - you won't magically find more torque. If the engine is slipping, you are not getting the motor's full potential to the rails and should consider adding some weight to increase traction .... but, be careful - adding too much weight can also create an adverse effect in that the engine itself becomes a load on the motor in addition to the cars it's pulling - it's a fine balance point.

Power and speed are determined by the gearing in your engine. The factory usually figures this out so you get a proto-typical speed for the type of engine you are running - your type of engine isn't designed to keep up with Amtrak. You want more speed, change the gearing - but the trade-off is less torque at the wheels for pulling. Want to increase torque AND speed ? - put in a better motor.

One last comment .... the motors we use in our model trains are rated at 12 volts. Running them at higher voltages is not recommended for extended periods of time. Many user manuals will even caution you on this. Lastly, why do you even WANT to run your trains that fast ? Have you considered looking into slot cars ?

Mark.

 

[Iron Horseman]

1. I have a Digitrax Zypher DCS51 which has a rated output power of 13.8V. The train goes around slowly.

Have you checked the programming in the locomotive's decoder to make certain it doesn't have an internal limit for the speed (V-MAX set lower - CV5 I believe)? Perhaps the speed isn't a controller issue at all.

 

[Nucular]

One last comment .... the motors we use in our model trains are rated at 12 volts. Running them at higher voltages is not recommended for extended periods of time. Many user manuals will even caution you on this. Lastly, why do you even WANT to run your trains that fast ? Have you considered looking into slot cars ?

According to Bachmann, the transformer that comes with the On30 Starter Sets puts out 16V DC at 0.1 amps. The motors are rated much higher than 12 volts. If not, Bachmann would have a huge warranty problem, as any child using the set, could run it at the full 16 Volts, and if the engine burns up, Bachmann would have to replace it/repair it. I have run N scale trains as a child at full volts for hours and nothing bad has happened. Even Bachmann train transforms are rated for an output of 15V or higher depending on the model. Why would Bachmann produce a transformer that puts out more volts than their trains can handle?

As for the speed thing, traveling at 23 MPH scale speed is too slow and unrealistic looking. Steam Engines in the late 1800s where traveling at speeds close to 100mph. The Hiawatha would travel at speeds in excess of 100mph. Surprising that railroads could do that in this case in 1935 yet we do not have high speed trains with today's technology. Whenever I watch the History channel and they talk about the old steam engines, I am also hearing of them traveling at speeds of 80+mph.

Trains in the past had to travel faster, they were a main source of mail delivery, and not getting mail to its destination on time was not a good thing.

My extra volt makes the train travel at a model speed of 33mph which for a narrow gauge train seems much more reasonable.

Also just because I have more volts to use, does not mean I will have to use them, it just gives more of a range. If the torque does decrease as motor rpm goes up, then just turning the throttle down a little will give me back that torque. In DC it is just as simple as turning a knob. Now in DCC to my knowledge the track is at a constant full voltage, but the decoder chip tells the train how many volts to use. Basically it just comes down to a simple turn of the knob.

The interesting thing is that, the engineer who sits next to me at work who has a degree in electrical engineering, claims that my train will be able to pull more cars at the higher voltage, as well as be able to climb steeper grades. He seems to make sense, I have a Lionel set up in my attic and when I need to go up a grade I need to give the train more volts, otherwise the engine stalls out. Pushing the voltage up seems to give the train more torque and power, yet this seems counter to the idea that as RPM goes up torque goes down. I have noticed that the wheels do slip on a steep enough grade with the On30 Bachmann engine. Adding weight as you suggested would most likely help that out.

 

[Selector]

Yes, my understanding is that the voltage is like pressure in a hose-pipe. The more pressure, the faster the flow where it counts. That would be the amperage, the work component of electricity.

I can't recall seeing a manual warning the user not to run the train at excessive voltage/speed for lengths of time beyond the norm. I have locomotives from at least six different suppliers/manufacturers, and nowhere did I read that the locomotive motors were somewhat underrated for the power pack supplied.

Nucular, while some passenger trains did run at speeds higher than allowed by FRA rules, it was not the norm, and certainly not the practice when the steam-powered Hiawatha ran. The FRA cap for passengers was at 79 mph, and that was nation-wide, and only on the highest grade of tracks kept in good order for such higher speed passenger service. I do know that occasionally hoggers would be given the go-ahead, or a tacit signal, to make up time if he could. On at least one occasion, a Pennsy T1 Duplex must have crested 120 mph on a 40 mile stretch, making up most of the nine minutes he was behind by the time he got to his final destination.

I find even a scale 79 mph seems too fast on my layout. I tend to run my Niagaras and Duplex, and the other Northern-types, at about 60 mph. It seems plenty fast to me, in scale, and it extends the actual running time around my 80 foot loop....between station stops.

 

[Iron Horseman]

According to Bachmann, the transformer that comes with the On30 Starter Sets puts out 16V DC at 0.1 amps. The motors are rated much higher than 12 volts. If not, Bachmann would have a huge warranty problem, as any child using the set, could run it at the full 16 Volts, and if the engine burns up, Bachmann would have to replace it/repair it. I have run N scale trains as a child at full volts for hours and nothing bad has happened. Even Bachmann train transforms are rated for an output of 15V or higher depending on the model. Why would Bachmann produce a transformer that puts out more volts than their trains can handle?

They are unregulated power supplies. That means it is only putting out 16 Volts or 15 Volts when there is no load. The bigger the load the lower the voltage. I would be surprised if an actual measurement of the voltage when there is a load on the rails is nearly that high. Only a regulated power supplies like they use in computers have a constant voltage output regardless of load.

As for the speed thing, traveling at 23 MPH scale speed is too slow and unrealistic looking. Steam Engines in the late 1800s where traveling at speeds close to 100mph. The Hiawatha would travel at speeds in excess of 100mph. Surprising that railroads could do that in this case in 1935 yet we do not have high speed trains with today's technology. Whenever I watch the History channel and they talk about the old steam engines, I am also hearing of them traveling at speeds of 80+mph.

Here you are talking apples and oranges and I alluded to this in my first post. On3 is Narrow gauge. I am guessing there has not been a narrow gauge loco in history that has exceeded 60mph unless it was wrecking. Most narrow gauge locos limp along on the equivalent of code 30 to code 55 rail and usually under 20mph.

The trains the history channel and you are talking about are on the high iron standard gauge and pulled with high stepping locomotives with huge drive wheels 69"-80". The Hudsons and Northerns could do this easy. Santa Fe had their class 5 rail (HO code 100 equivalent) "race track" from Trinidad Colorado to Dodge City Kansas. Here they often hit 100+ mph. But these are not narrow gauge locos with 36"-50" drivers. Buy the way, the SuperChief once derailed in Deerfield Kansas. It wasn't steam (the Blue Goose had been retired by then) but I believe they calculated it was going just short of 110mph at the time. So you are right, but not for narrow gauge. Side note - The speedometers in the Budd dome cars went over 100mph.

My extra volt makes the train travel at a model speed of 33mph which for a narrow gauge train seems much more reasonable.

Now that is a sensible comment. I can see a narrow gauge loco zooming along at 30 mph. Have you checked the max-V setting in the decoder? It might be limiting your speed.

 

[Retired Alex]

Also just because I have more volts to use, does not mean I will have to use them, it just gives more of a range. If the torque does decrease as motor rpm goes up, then just turning the throttle down a little will give me back that torque. In DC it is just as simple as turning a knob. Now in DCC to my knowledge the track is at a constant full voltage, but the decoder chip tells the train how many volts to use. Basically it just comes down to a simple turn of the knob.

I am by no means an expert on DCC but to my knowledge, the decoder applies full track voltage to the motor in pulses (DCC is square wave AC). At slow speed the pulses are short and as you speed up the length of pulses become longer. The decoders do not vary the voltage, from my understanding of what I am reading, to the motor.

 

[Selector]

I believe you are correct, Alex. It amounts to the same thing as metering the voltage to the can motor, but what is really taking place is the 'zeros' are shortened and lengthened, depending on the speed steps and speed tables being used. When you dial in max throttle, the zeros are both shortened and more numerous in a defined space on the signal.

 

[Nucular]

@Iron Horseman

There have been high speed narrow gauge trains developed, Japan initially developed high speed train technology on narrow gauge.

[h=3]"Fastest narrow gauge trains[edit][/h]The reduced stability of narrow gauge means that its trains cannot run at the same high speeds as on broader gauges[SUP][citation needed][/SUP], unless the tracks are aligned with greater precision[SUP][citation needed][/SUP]. In Japan and in Queensland, Australia, recent permanent way improvements have allowed trains on 1,067 mm (3 ft 6 in) gauge tracks to run at 160 km/h (99 mph) and faster. Queensland Rail's tilt train is currently the fastest train in Australia and the fastest 1,067 mm (3 ft 6 in) gauge train in the world, setting a record at 210 km/h.[SUP][3][/SUP] A special 2 ft (610 mm) gauge railcar was built for the Otavi Mining and Railway Company with a design speed of 137 km/h.[SUP][4][/SUP]
Compare these speeds with standard gauge or broad gauge trains which can run at up to 320 km/h (199 mph).[SUP][5][/SUP] The contrast is most evident in Japan, home of the Shinkansen, a network of standard gauge lines built solely for high speed rail in a country where 1,067 mm (3 ft 6 in) narrow gauge is the predominant standard.
Curve radius is also important for high speeds: narrow gauge railways tend to have sharper curves, which limits the speed at which a vehicle can safely proceed along the track." http://en.wikipedia.org/wiki/Narrow_gauge_railway#Fastest_narrow_gauge_trains

 

[timlange3]

What is the output of the transformer (power supply) going to the Digitrax command station? Measuring track voltage, is not simple, a multimeter will not do an accurate job. No matter what is on the rails from a DCC command station, the decoder is what converts the AC to DC and feeds it to the motor in a pulsed DC form. Don't expect to get full track voltage to the motor, the decoder will drop it as part of the rectification.

 

[Iron Horseman]

There have been high speed narrow gauge trains developed, Japan initially developed high speed train technology on narrow gauge.

Once again you are arguing apples against oranges. NONE of those railroads you mentioned are modeled by the Bachmann On30. All the Bachmann On30 are either US or Canadian (White Pass and Yukon) models. What you are saying does not apply to them. If you want to model those railroads then junk the Bachmann and do so.

I think you are inventing stupid arguments for the sake of arguing, just like my 11 year old does. So I am no longer going to try to help you solve your speed issue. Especially since you still haven't said if you have checked your MAX-V settings.

 

[Selector]

Nucular, you are taking singular exceptions that didn't end up much past the experimental stage, in modern history to boot, and insisting by your argumentation that it must have been the case in 1940 when diesels numbered in the hundreds and steamers still numbered in the tens of thousands. Please accept the instruction from two people who actually know that what you contemplate will be entirely fanciful. We, in turn, acknowledge that it's your time, your money, and ultimately your railroad. Just don't ask us for any affirmation.

Over and out....

 

[Nucular]

The funny thing, is that I never asked about realism or historical accuracy. I was asking about the maximum track voltage. All I wanted to know is if anyone knew if it was supposed to be run off of a standard "HO scale" transformer or an "O scale" transformer. From there you guys took it off into other directions, and no one really answered my question.

As for other comments. I did mention that I did check the maximum speed/throttle setting in the Digitrax unit and it was set at full output. I did mention that Digitrax's rated output on the unit clearly states 13.8 volts and it also states so in the manual. If Bachmann designs the engines for HO transformers or O scale transformers, which regardless I know it is HO from the Bachmann themselves having answered an email. I highly doubt that they would set the CV value lower. Not to mention that changing CV values is more along the lines of taking a shot in the dark. I did it once to an Atlas N scale engine, and I had to end up researching how to reset it back to factory settings because the value I changed caused the engine to coast for miles before coming to a stop.

Even above that, no one here has touch on the Oahu Railway and Land Company which had a double main line narrow gauge railroad that was used extensively in WW2 for transporting military equipment and personal in Hawaii. I have yet to find an article on its rated speed, but I am sure that it was greater than 20 or 30 mph.

Of course when you guys pick and choose what you want to talk about, take the topic off on tangents not related to the original question(s)/concern addressed, you look childish. Seriously, why does anyone here care how fast I run my layout? I only wanted to know the correct voltage settings so I do not burn up motors and trains. It seems like it was a pain in asking a straight forward question. Talk about a bitter community and individuals who have desire to stick on topic.

 

[Selector]

"As for the speed thing, traveling at 23 MPH scale speed is too slow and unrealistic looking. Steam Engines in the late 1800s where traveling at speeds close to 100mph. The Hiawatha would travel at speeds in excess of 100mph. Surprising that railroads could do that in this case in 1935 yet we do not have high speed trains with today's technology. Whenever I watch the History channel and they talk about the old steam engines, I am also hearing of them traveling at speeds of 80+mph."

I quote your voluntary participation in a diversion, above. It flowed naturally from your initial question and the information it contained. Your being a newcomer, we anticipated that you were looking for a rich, robust, and comprehensive return that would help you to avoid common pitfalls. Narrow gauge steam locomotives even attempting speeds in excess of 70 mph, let alone 100 mph, were not a reality. Are we bitter? Perhaps a little. You don't seem to be so keen to engage us with equanimity, but in attempting to justify your erroneous and preconceived notions. Ethically, we were bound to attempt to dissuade you from your erroneous path. Even if you were to successfully argue that I am wrong on that count, you could surely appreciate the courtesy.

 

[The Train]

Nucular a newcomer, it states on his profile that he has been here since April of 2011. Two years old and you are still considered a new comer.

I do not think that Nucular is upset by you trying to help, at least from what I can read. I just think he rather stick close to the topic on hand and not be bashed for wanting the option to run his trains faster if he would so choose to do. Hey, just because we can run them faster, does not mean we have to have the train at full blast, but the option is there for when you want to.

To answer Nucular's question, a typical HO rated transformer should do the trick. Standard HO voltage is 15 Volts.