6v Controller & Tomytech Portram

[Bernard]

I tested out my Tomytech Portram on a regular 12v DC Controller and it flies, so I have a couple of questions:

1) Is there a resistor I can put into it to regulate the speed and still use a 12v controller? Or
2) Has anybody made (or even rigged) up an electric 6v transformer with a speed control? (Don't want to go through a lot of batteries) Or
3) I purchased a 6v AA battery box w/switch at Radio Shack for 1.99 USD is there something I can get at Radio Shack that I can add to regulate the speed? (would a Potentiometer work?) Or
4) How is the Tomytech Battery Controller: http://www.1999.co.jp/eng/10072781

[Toni Babelony]

Pull the throttle half open?

[Bernard]

Pull the throttle half open?

LOL - but it flies when you just touch it to slow on the transformer.

[bill937ca]

I run mine with a Tomytec controller and I'm quite happy with the way it runs.

http://jtrains.wordpress.com/2009/09/23/the-tomytec-portram-low-floor-streetcar/

[David]

Pull the throttle half open?

LOL - but it flies when you just touch it to slow on the transformer.

What kind (brand/model) of controller is it though?

My Kato 12V controller has fairly smooth throttling - I can run some of my better engines so slow you have to put your nose right up to them to tell they're moving. By comparison my Model Power 12V controller does nothing up until about 20% throttle, at which point the engines blast off and it only gets faster after that.

[Bernard]

I run mine with a Tomytec controller and I'm quite happy with the way it runs.

http://jtrains.wordpress.com/2009/09/23/the-tomytec-portram-low-floor-streetcar/

I remember reading your blog Bill and it gave a lot of interesting details. Because of the placement of it's trucks I tested the Portram on some serve radii I made with flex track and it's the only train I know that can negotiate those sharp turns. But, by using the 6v controller will other trains run on that line?

One of the potential problems I'm anticipating is that the tram line I built uses a Miniatonics reverse unit that I believe works off a 12v transformer. Will it work off 6volts?

David - the transformer I'm using is an old little test one, it's made by (if you believe it) "Lionel" when it made HO trains. On my layout I use an MRC with pulse control.

[Toni Babelony]

My Kato 12V controller has fairly smooth throttling - I can run some of my better engines so slow you have to put your nose right up to them to tell they're moving. By comparison my Model Power 12V controller does nothing up until about 20% throttle, at which point the engines blast off and it only gets faster after that.

Could you tell me the complete specs of that controller? I have a Fleischmann controller that I want to replace with a more precise controller. It has 0~14V eff, 7.5VA and 0.6 Ampere. I'm interested to know if a higher level of Ampere really matters in a train's behaviour. (I know the KATO controller has 1.5 Ampere, but how does it manage in Volts and VoltAmpere?) Also, does anyone have good experiences with TOMIX controllers? (Which have 1.2 Ampere)

[David]

My Kato 12V controller has fairly smooth throttling - I can run some of my better engines so slow you have to put your nose right up to them to tell they're moving. By comparison my Model Power 12V controller does nothing up until about 20% throttle, at which point the engines blast off and it only gets faster after that.

Could you tell me the complete specs of that controller? I have a Fleischmann controller that I want to replace with a more precise controller. It has 0~14V eff, 7.5VA and 0.6 Ampere. I'm interested to know if a higher level of Ampere really matters in a train's behaviour. (I know the KATO controller has 1.5 Ampere, but how does it manage in Volts and VoltAmpere?) Also, does anyone have good experiences with TOMIX controllers? (Which have 1.2 Ampere)

The Model Power controller claims:

19V, 0 - 18VDC, 5.5VA

(it came with a Model Power "Christmas" type trainset, so it's as cheap as they come)

The Kato says 12V, 1.5A, so you're guess as to VA is as good as mine (I don't have a meter)

[Toni Babelony]

Hmm... I guess the specs for the KATO controller serve my needs better then a more powerful controller. I guess the trick is high Amps and low voltages for slow running. I'll do some research on this later. Thanks for checking!

[David]

I've actually been thinking of getting another DC controller to replace the Model Power one - there are a few out there with "momentum" control on them. So instead of instant start/stop the controller smooths out the change in power. Unlike DCC though it can't be configured to match the prototype.

[bill937ca]

David - the transformer I'm using is an old little test one, it's made by (if you believe it) "Lionel" when it made HO trains. On my layout I use an MRC with pulse control.

Lionel was normally O scale/O gauge.  Normally an O scale controller has far more voltage than N scale requires. Lionel's HO was short lived I believe.   Maybe you should double check, Bernard.

[Bernard]

David - the transformer I'm using is an old little test one, it's made by (if you believe it) "Lionel" when it made HO trains. On my layout I use an MRC with pulse control.

Lionel was normally O scale/O gauge.  Normally an O scale controller has far more voltage than N scale requires. Lionel's HO was short lived I believe.   Maybe you should double check, Bernard.

It's a 12v transformer for HO, but as you found the tram runs better at 6volts. Here is a test I just did at 12 volts:
<a href="http://www.youtube.com/v/4pv1jqalQnI" target="_blank">http://www.youtube.com/v/4pv1jqalQnI</a>

Now at 6volts battery pack:
<a href="http://www.youtube.com/v/cHBx1gJupOc" target="_blank">http://www.youtube.com/v/cHBx1gJupOc</a>

[inobu]

Here's some basic info and what I think is happening.

Power or electricity flows much like water. It looks and flows toward the least resistance and flow is based on the amount supplied and the paths ability to carry it. With water the path is a pipe or hose, with electricity the path is either wire or some form of metal. There is a slight variation between water and electricity and its reaction to bottle necks.

Water will cause a bulging effect where as electricity will cause a heating effect. When too much water builds up in the path or conduit it will bulge, expand and burst. When electricity builds up, it heats up and melt the path. This is what occurs when a fuse is blown. Fusing is how we protect electronic circuitry from over driving itself.

In reference to amperage it is compared to PSI or pounds per square inch. We know if we apply too much pressure to something it will eventually blow or pop. This is the same in amps. Apply too much amperage and things will melt. The difference here is the component will draw or pull amperage based on consumption. There is a relationship to voltage and amperage draw which we will see in a moment.    

Based on the circumstances here we see the tram scream around the track because 12 volts is being applied. The voltage is driving the motor, the higher the voltage, the faster the tram goes and also the higher potential current draw. If you touch the tram after that 12v run you will feel that it is hot. Remember if this was water we would see the indication of over driving by a bulge in the path. The over driving of electricity in this case can be recognized by the heating of the components or track. If we had infrared sight we would have a visual reference and see the cause and effects, because we don't have this vision we have the tendency to run things hot until it blows.  

So far we have a basic understanding of whats happening, the applied theory and visual results.

There is one more factor that we are missing which will bring everything to light. All of the controller that everyone is suggesting provides the basic elements to operate the tram but there is one gating factor between them all. The Scaling.

All of the controllers/power supply produces the voltage but it is the scaling of the voltage that created the limitation.

The knob scaling is the factor being missed. For example : A 12 volt power supply will have a 12 units scaling, meaning each click will represent 1 volts. A 12 volt train will operate a 50% on 6 clicks and have 12 different speed levels. If it were scaled to 24
units you would have 24 different speed levels and each click applying .5volts
 
Put a 6v tram on a 12v - 12 scaled controller you will only have 6 units until the tram is maxed. Place the tram on a 36 scaled controller and you will have 18 speed levels. This is because the 12v is broken up into 36 units or .33v increments.  After 18 clicks you will be at 5.94 volts or the max 6v.

Bernard, the controller you are using is not providing the voltage in increments that the trams need to use. The 6 volts falls within the controllers 0 to 12 v rating but the controller's output voltage increments up too much for the tram. So when you turn the knob it sees 4v to 5.5 to 7 to 10 which is out of its range. A controller designed for the tram most likely will increments up in .25v and max at 6v. This will give you 24 speed level for example.  

You are correct in searching for a Potentiometer( its a variable resistor) but make sure that it will increment to the correct scaling needed to operate the tram.  

Hope this helps.

Inobu

[Bernard]

Inobu - It helped a lot and I liked your analogy using water. One other test which I failed to mention is I took an Tomix ED76 and ran it with that transformer and it was fine. It isn't the best controller just a quick tester I have on my desk to check out a train.
As for the potentiometer, there is a variety to chose. Which would work for the 6v project? Here is the link at Radio Shack: (And the guys who work at my Radio Shack aren't of any help. I had to explain what an alligator clip is and what it's used for.)
http://www.radioshack.com/search/index.jsp?kwCatId=&kw=potentiometer&origkw=potentiometer&sr=1

[inobu]

I think you have the general idea and just need to understand the final points.   

Here is a link that give a good visual to what you are dealing with. Although it for audio its principles are the same.

This web site is the best and pretty much explains things like I do but with more tools and detail. The author did a great job.

Just visualize this controlling the tram and watch the DC output voltage to the right. This is what you want to replicate only maxing out at 6 volts instead of 7.

http://www.bcae1.com/images/swfs/potentiometerslider.swf

http://www.bcae1.com/ Main page.



Inobu






 

[to2leo]

Wow this is like a Gr. 10 Science class on electricity.  I hope Kato will make the tram at scale speed.

[CaptOblivious]

The amps rating on a throttle is not like water pressure, and it will not make a difference for slow running, or fast running, or anything like that. It is a capacity. Each item you put on the track—a light, a motor—will consume some current. This rate of consumption is measured in amps. The amount of current consumed is proportional to the voltage put on the rails. Notice how the lights burn brighter at 12V than at 6V? That's because they are consuming twice as much current. But notice that, contrary to the "water pressure" analogy, the throttle isn't pumping current to the tracks, but rather, these items are pulling it from the throttle. If the total amount of current being drawn by items on the rails exceeds the throttle's rating, the throttle will burn up, or shut down (most likely). That is why a larger rating is better: You can run more trains (or bigger trains) off of 5A than 1A.

E.g.: My Kato 11-car E231-500 with full LED interior lights, when the throttle is wide open (12V put on the rails), draws about 8mA per light, and another (I'm guessing!) 500mA for the motor, for a total current draw of 610mA. My Kato 7-car 651 Super Hitachi with full bulb interior lights, draws about 55mA per light, and another (say) 500mA for the motor, for a total draw of 965mA. Now, if I had a Kato throttle, rated to 1.5A, I could run one of these two trains, but not both at the same time: The throttle would overheat, and either fry or (if it is well-designed), simply shut down. But if I run only one train, then the throttle will only output as much current as the components in the train draw (i.e. 610mA for the E231 or 965mA for the 651), and no more.

So, the amp rating of a throttle has no bearing on how well a train runs at low speed. Rather, that is determined by the quality of the throttle's output: They are often quite "noisy", not putting out a constant 6V at 50% throttle, but a sort of wobbly, noisy, 5.5V oops! 6.2V no wait! 5.8V, crap! 6.5V!. This noise is constant, regardless of the voltage, and so has a much greater effect at low voltages, which affects slow running. The result is that you get a train that jumps and starts at lower speeds (and it jumps and starts at higher speeds too, but since its already moving pretty fast, you can't tell; that's what I mean by the noise being exaggerated at lower voltages). So, low speed running has everything to do with whether the thottle can put out a constant, solid voltage; most are very noisy indeed!

One last point for Bernard. There are three variables that characterize an electric signal; we know voltage and current: Resistance is the third. Resistance is a measure of how much current a component draws at a given voltage level; one way to think of it is how hard a component resists the flow of current. The three values are related by Ohm's Law:
V=IR
Where V = voltage, I = current, and R = resistance. Solving for I:
I = V/R
So, for Bernard: Slow running is accomplished by reducing the current draw of the motor. Ohm's Law shows that there are two ways to accomplish this: First, by reducing the voltage on the tracks (tell us something we don't know, CaptO!), or by increasing the resistance of the motor.

So, if you like how it runs at 6V, but want to run it on a 12V throttle, you will need to measure how much current the tram is drawing at 6V. Knowing that value, you can solve Ohm's Law for R:
R = V/I
where V = 12V (NOT 6V, since we're picking a resistor to run the train on a 12V throttle as though it were running unmodified on a 6V throttle) and simply wire a resistor with that value between one of the motor tabs and the corresponding pickup (like doing half a DCC install). Done! Easy as 3.141592654

[Bernard]

Thanks for both explanations. Now I remember why I was an English Major in college. 
Adding a resistor will solve my problem because on the layout as I said, I need to use a 12v transformer for the reverse unit that also operates the tram. As I see it (and I'm probably wrong) since the tram runs well at 6v I need a resistor that will increase the resistance to the motor. ( in half?)

[CaptOblivious]

Thanks for both explanations. Now I remember why I was an English Major in college. 
Adding a resistor will solve my problem because on the layout as I said, I need to use a 12v transformer for the reverse unit that also operates the tram. As I see it (and I'm probably wrong) since the tram runs well at 6v I need a resistor that will increase the resistance to the motor. ( in half?)

It's easier to measure the current going to the motor on a running train than measuring its resistance (which actually can be different when stopped than when running), because you don't have to chase the train around with your probes to measure current :D

To measure current, grab your ammeter (or set your multimeter to ammeter mode), and wire it between one of the throttle leads and the corresponding rail, and turn the battery pack on.

To measure resistance, grab your resisto-meter (can't recall the proper term...;P ) pull the shell of the train, put one probe to each motor tab, and turn the battery pack on…oops, there goes the LRV…can you keep up?

[inobu]

Amperage relates to voltage like pressure relates to water. Here is the irony, A waterjet can cut through steel just as a arc welder melts it.

The ideology is you cannot fill a water balloon to capacity with a tea spoon just as you will not start a car with a 12v duracell battery. You need pressure to fill the balloon and you need amperage to crank the starter both are drivers so to speak.

Anyway, the reference to water is a basic analogy that leads the reader to visualize or understand that current flows and has capacity levels based on supply and its consumption is based on demand.

You will be amazed at what power can do. The reason guys complain about DCC burning up is due to resistance. What they dont realize is if your connection is poor on the receivers pickup it induces resistances. This resistance builds up heats. Run it for a while and eventually it will burn everything up.  

Here is my word of caution. Remember that current turns onto heat when it hits a bottle necks. Resistance is a bottle neck. I'm a true believer in designing and engineering to specs.

If it were me I would use Tomix battery controller and wire a 6v power supply to the battery leads and continue on with what I was doing.    

Inobu





 
 

[CaptOblivious]

Your word of caution is well-placed. I informed Bernard about power and heat dissipation in a PM.

For the curious, power is the amount of energy a resistor has to dissipate at a given current:
P = I^2R (that's current-squared times resistance). You have to use a large enough Wattage resistor to dissipate the energy (read: heat) that the resistor uses up!

[Shashinka]

Your word of caution is well-placed. I informed Bernard about power and heat dissipation in a PM.

For the curious, power is the amount of energy a resistor has to dissipate at a given current:
P = I^2R (that's current-squared times resistance). You have to use a large enough Wattage resistor to dissipate the energy (read: heat) that the resistor uses up!

Thankds for blowing up my mind. susan will not be thanking you tonight

[CaptOblivious]

Your word of caution is well-placed. I informed Bernard about power and heat dissipation in a PM.

For the curious, power is the amount of energy a resistor has to dissipate at a given current:
P = I^2R (that's current-squared times resistance). You have to use a large enough Wattage resistor to dissipate the energy (read: heat) that the resistor uses up!

Thankds for blowing up my mind. susan will not be thanking you tonight

What, multiplying three numbers too hard for you? :P (sorry, couldn't resist snarky comment…)

[Shashinka]

Your word of caution is well-placed. I informed Bernard about power and heat dissipation in a PM.

For the curious, power is the amount of energy a resistor has to dissipate at a given current:
P = I^2R (that's current-squared times resistance). You have to use a large enough Wattage resistor to dissipate the energy (read: heat) that the resistor uses up!

Thankds for blowing up my mind. susan will not be thanking you tonight

What, multiplying three numbers too hard for you? :P (sorry, couldn't resist snarky comment…)

According to the Simpson's, the ability to multiply three digits is considered witchcraft.

[Toni Babelony]

Thanks for the information!

So, if I understand correctly, it's the quality of the throttle-control (the potentiometer) and not the level of Amps to ensure smooth running on low speeds. No need to replace my old Fleischmann controller then.

I've found some nice circuits on the internet and in books to build an interesting throttle control. Here is one website with interesting circuits: http://home.cogeco.ca/~rpaisley4/CircuitIndex.html#Throttles is there one that can be recommended for slow running?

Thanks in advance!

[Garth]

A good throttle for running the Port Tram is a Z-scale one put out by Akia and it is rated at less than an amp at 10vdc. You can find it under Other Z at Hobby Search. It will also be made in different colours and with the Crown PRMLoco name on it in the near future.

For n-scale unless you are running alot of engines at the same time you do not need more than one amp. Most of out motors draw .3 of an amp while running.

If you use a power supply with excess amps and you hae a short you are going to burn something up so put a lamp in the line like the brake light of a car then if you short someting out the filament lights up and things wil get worm at the site of the short but do not usually burn up.

The best type of throttle for the Port Tram and other low current devices (which most modern N-scale qualify as) is a transistorized Throttle where the reostat or potentiometer is controlling the bias of a transistor which regulates the voltage to the track and the motor. With older transformers with wire wound potentiometers as they age you loose the isolation or insulation on the bottom windings and they short out so the thing starts at 3 or 4 volts instead of 0v. 


In general you should be able to run 3 modern N-scale engines on 1 amp power supply without a problem and using older motors the limit might be 2 engines. If you go all the way back to the open frame type motors of treble O then only 1.

Cheers Garth

[CaptOblivious]

Toni, that's correct!

And: Thanks, Garth, that's very helpful.

In general you should be able to run 3 modern N-scale engines on 1 amp power supply without a problem and using older motors the limit might be 2 engines. If you go all the way back to the open frame type motors of treble O then only 1.

Or, if it's like my Super Hitachi, with high-draw bulbs lighting each car, you're doing good to run even just that one (it makes my Tomix throttle heat up really warm after just a few minutes running).

[Bernard]

Okay through trial and error I found a solution and at no additional cost to me.
From Bill's previous post, I learned that the Portram works best at 6v and he uses the Tomix battery controller to accomplish this which is perfect for this tram. Since I'm using it on a permanent layout I wanted to use an electric power supply that would co-exist with what I'm already using. Here is what I came up with:
I found 2 controllers from an Aurora race car set to regular the flow of current to the track. I hooked them up to the DC fixed posts on one of the transformers I am using on another line then from the controllers hooked them up to the individual tracks. I works beautifully! Here is a photo of the controllers:

[CaptOblivious]

cool! How do those things work? What's the one on the right, specifically?

[Bernard]

cool! How do those things work? What's the one on the right, specifically?

Don - They're really the same controller but different years that they were made (back in the 60s and you weren't even born. )
They are to Aurora Modelling Motoring race car sets which are attached to a 12v transformer. I had them in storage and thought if they worked on the race cars why not the Portrams? And they do. I'll post videos of the results.