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Tramcar Trev
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Allow you to use a single 3.3 Lion cell to boost voltage to whatever you need. Found on eBay: http://www.ebay.com.au/itm/LM2577-DC-DC-3-34V-4-35V-Digit-Step-Up-Adjustable-Power-Supply-Converter-Module-/131164010981?pt=LH_DefaultDomain_15&hash=item1e89fbf9e5 2.5A cap
http://www.ebay.com.au/itm/LM2587-DC-DC-Boost-Converter-3-30V-Step-up-to-4-35V-Power-Supply-Module-DA-/181527342570?pt=LH_DefaultDomain_15&hash=item2a43df6dea this one they claim can give 5A output....

I am going to get a couple and experiment, it would mean I could get away with a physically smaller battery but get a much higher voltage, a higher voltage means less current means less battery drain and also will give me a higher motor torque which would mean better slow speed running. Or am I wrong?
Probably not in the right place....

pipopak
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I am not an electrician, but I know you can't create energy. A higher voltage (plus whatever current the module uses) means shorter battery charge life. But I am curious about the matter anyway. Jose.

Herb Kephart
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Correct Jose.

Watts, the correct measure of power available or consumed, are calculated as volts X amps.

The converter cannot be 100% efficient.

So the total available power has to be less.

But-- the converter is smaller than an additional cell if you want/need more voltage, A single, large as possible cell (misnamed battery, as a battery is a group of cells) eliminates the need for balance charging, if that is thought necessary

The linked converter has a led readout, the purpose for which isn't mentioned--I have to suspect that it reads output volts, and if so is something not needed for our purposes. In our needs, the voltage can be set by what performance is desired. I have seen on Fleabay converters that do not have the readout, which has to mean a smaller overall size, and less cost.
Herb

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I have just bought some of these......

http://www.technobotsonline.com/pololu-step-up-voltage-regulator-1.5a-max-i-p-12v-output.html

.....to play with in OO gauge.

I'll let you know how they go! See how small they are 0.32" x 0.515"

Tramcar Trev
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Dave H wrote:
I have just bought some of these......

http://www.technobotsonline.com/pololu-step-up-voltage-regulator-1.5a-max-i-p-12v-output.html

.....to play with in OO gauge.

I'll let you know how they go! See how small they are 0.32" x 0.515"

They look the bees knees exacary what I wanted 12V from 6.6V I'll have to do some practical measurement and see If I can get away with 1.4A draw...

Tramcar Trev
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Ok I have had a bit more of a scratch around and found these sans the digital readout and they can handle 3A; http://www.ebay.com.au/itm/DC-DC-Step-up-Adjustable-Power-supply-voltage-Converter-Output-5V-35V-Module-/141051821846?pt=AU_B_I_Electrical_Test_Equipment&hash=item20d757ff16

And heatsinks to make them last longer; http://www.ebay.com.au/itm/131014795047?tfrom=141051821846&tpos=unknow&ttype=price&talgo=origal

they are not small however but much smaller than another cell...

fallen
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Herb is right, there is no free lunch. If you double the output voltage you at least double the input current, so you need fewer cells but they each need bigger capacity. You do have more flexibility on the voltage supplied though.

However there is another advantage. If you have a big single cell it is easy to charge. If you have two smaller cells you need to provide for balance charging of the two cells which is slightly more complicated. This can make the installation easier.

Frank

Last edited on Tue Feb 17th, 2015 06:12 am by fallen

bobquincy
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I have been using the Pololu converters to step up 2xAA to 3.7 V. One of the smaller ones (1.2 A input) got overloaded with a motor pulling about 700 mA and would shut down until I closed the throttle for a short time. No damage done though.

Most of these are rated for input current which is the output current times the ratio of output voltage/input voltage divided by the efficiency: in my case 700 mA * (3.7/2.4) /0.8 = 1.35 A input current. I switched to one of the 2A converters and it can handle the 700 mA output.

One of the benefits is that the output voltage stays constant until the battery is really exhausted.

Herb Kephart
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The 80 - 90% efficiency means that 10 - 20% of the supplied current is dissipated as heat. Some of the ads you will notice offer ''heat sinks''. These keep the chip cooler and in marginal cases may eliminate thermal shut down.
You don't need to buy their aluminum finned extrusion, as it takes up considerable space. Any piece of thin aluminum will help, and of course the larger the better. A coat of flat black helps to shed the heat also. Be sure to put some heat conducting paste between the chip and the aluminum, what ever size you use, Beer and soda cans are a good source, and can be cut with scissors once the can is disassembled to a size dictated by the space available. Sand both sides of the metal (the inside has a clear coating) before painting with the flat black, and leave the section that will contact the chip bare, excepy for the heat compound.

http://www.ebay.com.au/itm/Gold-CPU-processor-heat-conducting-paste-gt-3-8WmK-PC-Thermal-Heat-sink-cooling-/281307590991?pt=LH_DefaultDomain_15&hash=item417f3d314f

Various size quantities, this is the smallest (and cheapest) at the present time on Ebay 

Strictly speaking this isn't necessary, but a cool chip is a happy chip.

Herb


           

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http://www.ebay.com/itm/with-ENABLE-DC-3-3V-3-7V-5V-6V-to-12V-Boost-Converter-Power-Supply-Step-up-Board-/271366097420

Tramcar Trev
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Various heatsinking missadventures led me to this stuff double sided thermal tape here its cut into 1" squares but it can be got in A4 sheets; http://www.ebay.com.au/itm/20pcs-25-25mm-Sticker-Square-Sided-Thermal-Adhesive-Tape-for-Heatsink-heat-sink-/291319829617?pt=LH_DefaultDomain_15&hash=item43d403d471

Very handy means usually no mechanical fastening is needed...

Tramcar Trev
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mwiz64 wrote:
http://www.ebay.com/itm/with-ENABLE-DC-3-3V-3-7V-5V-6V-to-12V-Boost-Converter-Power-Supply-Step-up-Board-/271366097420 They are neat but only handle 450mA.

Tramcar Trev
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Herb Kephart wrote:
The 80 - 90% efficiency means that 10 - 20% of the supplied current is dissipated as heat. Some of the ads you will notice offer ''heat sinks''. These keep the chip cooler and in marginal cases may eliminate thermal shut down.
You don't need to buy their aluminum finned extrusion, as it takes up considerable space. Any piece of thin aluminum will help, and of course the larger the better. A coat of flat black helps to shed the heat also. Be sure to put some heat conducting paste between the chip and the aluminum, what ever size you use, Beer and soda cans are a good source, and can be cut with scissors once the can is disassembled to a size dictated by the space available. Sand both sides of the metal (the inside has a clear coating) before painting with the flat black, and leave the section that will contact the chip bare, excepy for the heat compound.

http://www.ebay.com.au/itm/Gold-CPU-processor-heat-conducting-paste-gt-3-8WmK-PC-Thermal-Heat-sink-cooling-/281307590991?pt=LH_DefaultDomain_15&hash=item417f3d314f

Various size quantities, this is the smallest (and cheapest) at the present time on Ebay 

Strictly speaking this isn't necessary, but a cool chip is a happy chip.

Herb


           

We can have a really heated debate here Herb. While I agree that a cool chip is a happy chip I beg to differ on painting the heatsink. When I was involved with some students building an electric car the university did tests on the efficiency of heatsinks. Black anodising came out with the best performance followed by natural grit blasted aluminium then "mill finish" aluminium and last painted Aluminium, the single coat of paint acted as an insulator because at the interface between the paint and the heatsink there was a layer of air. Grit blasting increased the surface area by a staggering 30% over a finely machined surface... Generally the more surface area you can get the easier it is for the heatsink to dissipate the heat ergo slim people suffer the effects of heat more than portly built people...

Tramcar Trev
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So getting back to the step up converters, I specifically want one for my Baldwin Tram motor, currently I use a 3 cell 6.8ah Lipo battery which gives me 9.9v but performance is not flash especially at slow speeds so I made up a 4 cell Lipo 2.2ah battery and that gives me 13.2V and the improvement is amazing but its too tight inside and 2.2ah gives me about a 45min run so one of these step up contrivances will fit in and will let me up the voltage from 9.9 to 12-13 V and let me get it all under the boiler, so to speak....

My electric cars (all use the same crappy Bachmann motor block) seem happy at 13.8 v but because the power supply is "intermittent" due to imperfect contact with the trolley wire and the rails I use one of these 1F "super Capacitors" across the Rx power bus to keep the Rx "alive". Its very realistic to have the headlights flickering but the Rx needs constant power, if it dies everything stop until it finds the signal again. The BEC on the ESC keeps it charged and it smooths out the supply of dc to the Rx...
http://www.ebay.com.au/itm/7mm-x-20mm-Radial-Electric-Farad-Super-Ultra-Capacitor-5-5V-1F-/301483815308?pt=LH_DefaultDomain_15&hash=item4631d5f18c

I have probably explained this elsewhere (maybe in the RC section)...

Herb Kephart
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Trev--

Thanks for the info on heat radiation! Very interesting that grit blasting made such a difference--

Reminded me of all the motorcycle cylinders that I painted black, thinking that I was doing the right thing.

Herb

mwiz64
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Tramcar Trev wrote: mwiz64 wrote:
http://www.ebay.com/itm/with-ENABLE-DC-3-3V-3-7V-5V-6V-to-12V-Boost-Converter-Power-Supply-Step-up-Board-/271366097420 They are neat but only handle 450mA.

How much current are you pulling? Have you ever measured it? My guess with the battery sizes people here are talking about and the duration they are getting that nearly half an amp is pretty good. Think about it, that's over 5 watts. Of course, every scale and every application has a different need.

Tramcar Trev
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mwiz64 wrote:
Tramcar Trev wrote: mwiz64 wrote:
http://www.ebay.com/itm/with-ENABLE-DC-3-3V-3-7V-5V-6V-to-12V-Boost-Converter-Power-Supply-Step-up-Board-/271366097420 They are neat but only handle 450mA.

How much current are you pulling? Have you ever measured it? My guess with the battery sizes people here are talking about and the duration they are getting that nearly half an amp is pretty good. Think about it, that's over 5 watts. Of course, every scale and every application has a different need.

In the application I'm using I have a 1.5amp stall (about 800ma running) current on the main motor and my "smoke creator" uses an amp, but it does create a lot of smoke....

Attachment: DSC_1357.JPG (Downloaded 32 times)

Tramcar Trev
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Herb Kephart wrote:
Trev--

Thanks for the info on heat radiation! Very interesting that grit blasting made such a difference--

Reminded me of all the motorcycle cylinders that I painted black, thinking that I was doing the right thing.

Herb


The coarser the grit blast the more surface area too but as you may remember to original VW beetle with the engine block that split horizontally and were air cooled and it only took a few drops of oil to leak around the joint and dust and grunge would accumulate and next thing the engine would seize....
Then there is the black car/ white car debate and black cars get hotter in the sun yes of course they do. We also busted that myth, the black car heats up a hell of a lot more quickly but gets to a point where it re radiates the heat faster than the white car which actually gets hotter than the black car but because its white the general public believe thats they are cooler on a summers day...
Black and white cars also get dirty at the same rate but the black car shows the dirt whereas the white car hides it...

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Tramcar Trev wrote: Then there is the black car/ white car debate and black cars get hotter in the sun yes of course they do. We also busted that myth, the black car heats up a hell of a lot more quickly but gets to a point where it re radiates the heat faster than the white car which actually gets hotter than the black car but because its white the general public believe thats they are cooler on a summers day...
Black and white cars also get dirty at the same rate but the black car shows the dirt whereas the white car hides it...

It's occasionally been suggested that another issue might be how well different coloured surface finishes reflect light of different frequencies.

The suggestion was something along the lines of white surface finishes reflecting enough light at visible frequencies (red ... violet) - to a similar enough extent - to appear white under sunlight.

By the time the light frequency moved down to the infra red (effectively "heat") end of the spectrum, any pigments, bases etc in any surface finishes might well behave very differently from how they might have in the visible spectrum.

I don't doubt that these differences apply just as much to bare metal - with differences depending on how the surface has been prepared (polished, grit blasted etc).

I also don't doubt that there are many people better qualified than me to comment on stuff like this.


Also of interest to me was the initial topic of this thread - voltage step up converters.

I suspect that the key issue with using these is how much current you actually need to draw out of them. This might seem like a strange statement - but I'm not sure that it is.

A couple of years back - at an engineering trade show - I was given a "white" LED torch with a step up converter (aka "Joule thief") built in (very useful it is, too).

I'm not sure how efficient it was - but it probably doesn't need to be particularly efficient.

The whole point of this device is that it allows me to drive a reasonably usable torch from 1 "AA" cell that would otherwise have been discarded. I might only get (say) an hour out of each cell - with a pretty low current driving the LED - but it's enough so I can see my way home, if I've got a bit of a walk after I get off a coach.

It's also use I would not have got out a cell that no longer had enough "juice" to do anything else - so I'm not exactly complaining if the thing isn't quite as efficient as it might be.


Would I use a similar circuit to drive anything that needs a significant current? Probably not - if nothing else, it probably wouldn't work. However, for a really low current application - where it allows me to get away with using batteries which would otherwise be completely useless - I can't think why I wouldn't wish to use something like this.

For me, the key is how much current it needs to supply - and whether I'm actually too bothered if the thing isn't quite as efficient as I might sometimes wish.


Anyway, sorry about the interruption - back to the thread.


Regards,

Huw.

Last edited on Fri Feb 20th, 2015 01:08 am by Huw Griffiths

Si.
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A good rule of thumb (no pun intended) is...

...if you can hold your finger on a sinked chip...

...all is well & it will give longlife.

This is about 50c on the sink.

The junction-temp inside the chip can be 100c however.

The most significant improvement in sink performance...

...is usualy air-flow, whether forced or convection.

Vertical fins in free-air is the way to minimise sink size.

Alot of these DC-DC converters are intended for 'microelectronics'...

...rather than 'power-electronics' ie. motors.

1A load is quite a tall order without good sink AND ventilation !

(thankgoodness for thermal shutdown !)

To be honest, If I was doing this...

...I would look at different size/shape cells.

I think a properly running DC-DC converter with decent sinking...

...would take up WAY MORE room than an additional cell or two...

...and would be less efficient & probably less reliable in 'power' applications.

Cheers.

Si.

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I think you're probably right there.

Although step up converters / "Joule thief" circuits certainly have their uses, I've always seen them as niche - partly because of likely efficiency issues - partly because of getting rid of the heat generated, thanks to the inevitable losses.

As for working temperatures for "chips" - well, any circuits really - I think it's probably best to take a line of:

Cool is cool - hot is most definitely bad news!


OK - I'm sure that some people are probably cringing at that last comment - but I suspect that many people here are agreed on the general sentiment behind it.

Many of us have also seen what happens when electronic components get too hot - or are otherwise wrecked through poor circuit design / construction or abuse.

The "magic smoke" might be an optional extra - unfortunately, the cost of replacement parts and time spent fitting them come as standard.


Personally, I might be happy with my "Joule thief" LED torch - but then I'm only talking tens of milliamps (and correspondingly low power / heat levels) - anyway, I'm sure the metal body on this thing might help with heat dissipation.

I find this torch very useful - I might also experiment with similar circuits for (very) low current applications - but I know these circuits have limitations. For this reason, i wouldn't even contemplate using them to drive anything "meaty" - each to their own, like but, as I've always been known for being risk averse, I think I'll play safe here.


Regards,

Huw.

Last edited on Fri Feb 20th, 2015 02:20 pm by Huw Griffiths

Herb Kephart
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OK--heres a question for those of you with an electrical background.

Assume radio control, a single cell and an ADJUSTABLE step up board. 

Also assume that the loco runs at the desired speed at 9 volts

Would the watts (and in this case heat) be any different if the adjustable were set to 9 volts--or---if it were set to 12 volts and the speed limited to 9 volts by the radio throttle?

I can think of arguments --some of which are obviously  bogus--both ways.

What say you?

Herb

Tramcar Trev
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Herb Kephart wrote:
OK--heres a question for those of you with an electrical background.

Assume radio control, a single cell and an ADJUSTABLE step up board. 

Also assume that the loco runs at the desired speed at 9 volts

Would the watts (and in this case heat) be any different if the adjustable were set to 9 volts--or---if it were set to 12 volts and the speed limited to 9 volts by the radio throttle?

I can think of arguments --some of which are obviously  bogus--both ways.

What say you?

Herb

Ok.... If the speed control is PWM (which it would probably be) then the motor is getting the full voltage, its just switched on and off with varying frequency (5 -10Khz or higher, when you are looking at an ESC which will give you PWM control this is the thing you should be looking at, the higher the frequency the smoother the control -so I'm told) to control the speed. This is why PWM is so good as the motor can deliver full torque at low speeds. This then opens up another can of worms cuz some electric motors do not enjoy PWM control. So that changes things.... Say half throttle = half speed the motor is drawing full voltage and full current but only half the time.
Ok, so I think what you are asking is how much waste heat is there going to be and how hot is hot and is this going to melt my plastic body? I dont know; the calculations are way beyond me but I would assume if you had one of these gizmos in your circuit and were converting (as I want to do) 9vdc to 12 VDC there is going to be a lot less heat( generated by inefficiency and the process of conversion) than if you were converting 9vdc to 18vdc infact if its linear say 50% less. Converting 9vdc to 9vdc I would assume would only use the % of "inefficiency" in the converter and convert that to heat.
This may be totally spurious but I'm not going to be offended if I'm wrong, I'm a tram driver not an electronics nerd...

Strewth the way I answered that I should have been in politics....

Last edited on Fri Feb 20th, 2015 09:33 pm by Tramcar Trev

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I am not much of a tram driver but I *am* an electronics nerd! ;) Trev was kind of on the right track, here is some data:

Looking at the curves given for some Pololu (and other) step-up regulators we see a similar power loss for different Vin/Vout, dependent mainly on output wattage. With Vin=3.3 and Vout =5 or Vout=12 the efficiency is similar and the power loss (heat) is also similar. It would not matter significantly if we ran our 9 v motor from 9 V at 100% duty cycle PWM or at 12 V with 75% duty cycle PWM. The average power in and the average power out are about the same, as is the average power lost.

At low (10 mA) and high (>1 A) outputs the efficiency curves are not linear but in the range that we are likely to use (100 mA to 1 A) the efficiency curves are close to a straight line.
For more curves see: http://cds.linear.com/docs/en/datasheet/35392fc.pdf

The average power lost due to inefficiency is what generates heat. The device runs at a high frequency and the temperature will not change that quickly, it takes at least a few seconds. Most of the ICs are rated to operate up to 85 C. Some devices have a thermal shutdown at about 150 C die temperature, the surface of the device will be lower. It may not be enough to melt plastic but it is probably best not to have the IC in contact with a plastic surface that could be seen, just in case. Most devices with a thermal shutdown will restart when the temperature drops by about 20 C.

If they are consistently overloaded the tipoff is repeated cycles of run-stop-run, as I had when using a converter that was just a bit too small.

boB

Last edited on Tue Feb 24th, 2015 04:40 pm by bobquincy

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Ok, glad someone is on top of this... Another solution now presents itself, a 6 cell LiPo battery which gives 22VDC is at hand. Do I a) split off 2 cells and create a 14V battery or do I b) drop the voltage via a MC78T12 12V 3A (or similar) Voltage Regulator?

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Hi Trev.

Forget DC-DC converters...

...and voltage-regulators.

Only use the cells you need.

14 Volts sounds great !

No heat, no heatsinks, no thermal-shutdown, no reliability issues, no problems choosing the correct DC-DC converter for 'power' apps.

Only add extras if you ABSOLUTELY HAVE TO.

You don't have to.

Cheers.

Si.

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That's great advice if you can balance charge the battery. If not, you're playing with fire, literally. 3 cells wired in series (3S in the lipo world)is 12.6v at full charge.

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One thing worth thinking about is how fast you want your locos to run.

Many RTR locos will do a scale 150mph on 12v applied directly to the motor (remember that the 12v applied to the track does not all make it to the loco, there are voltage drops along the wires, along the rails, and at the points where the wheels contact the rail and the pickups).

Many modern locos will travel at realistic speeds on only half the nominal voltage applied direct to the motor, sometimes they will need even less.

I find many of my 009 locos (basically n gauge, nominal 9v) will work quite satisfactorily on a single LiPo supply of 3.7v.

I suggest trying the locos out with a voltmeter on the track to see what voltage they need for a reasonable speed, it will give you an idea of what is really needed. To be more accurate, you can attach a pair of long flexible wires to the motor and try driving those from the controller with a voltmeter across them.

Frank

Last edited on Wed Feb 25th, 2015 06:24 pm by fallen

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mwiz64 wrote:
That's great advice if you can balance charge the battery. If not, you're playing with fire, literally. 3 cells wired in series (3S in the lipo world)is 12.6v at full charge.Each cell has a protection board across the terminals. Shuts the cell down over 5a and when the voltage drops to around 3v. This battery comes with its own charger and I suspect that the pcb,s on each cell somehow. control the charge

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Tramcar Trev wrote: Ok, glad someone is on top of this... Another solution now presents itself, a 6 cell LiPo battery which gives 22VDC is at hand. Do I a) split off 2 cells and create a 14V battery or do I b) drop the voltage via a MC78T12 12V 3A (or similar) Voltage Regulator?I agree with Si, if you can use just batteries there is no point in adding extra devices. 

In any case we don't want linear regulators (like 7812 types) for significant current loads.  Linear regulators shed the excess voltage mainly as heat, going from 22 V to 14 V at 1 amp gives off about 8 watts!  It also gives about the same battery run time as if we used 14 V in the first place.

Switching regulators (like Pololu and others) are much more efficient then linear regulators although the linear types are ok for low current (like powering some LEDs).

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Ok so we've got everybody trying to jam more batteries where they won't fit so they can get almost 12 volts to operate their engines.

Has anybody thought of perhaps changing the motor to a lower voltage. Seems we are stuck in 12 volt motor paradigm.

I did 3 HO steamers. Changed them from 12 volts to 6 volts. Still have the same pulling power as the 12 volt. Only I'm not running batteries on the as yet. I used voltage from the track. It can be AC, DC, or DCC because I run a voltage rectifier to supply 6 volts to the control circuit, a Deltang RX41d Receiver.



Works for me.

Bernd

Tramcar Trev
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That would work but I would have to find a 6V motor block, the bachmann ones I use do not seem to have a generic motor available.

Helmut
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Alas only the hobby's dinosaurs ( like me ) seem to dare to tackle the mechanics to fit their desires. I even put in a 3v motor where appropriate. Those 3...6v can motors ( not to be taken for instrument motors, mind you ) of nowadays are a lot more effective than the open-frame 12V ones they still put in the models.

@Bernd
Why don't you put in a step-down converter 0f 0.5A rating, same size as the 78xx series? They have a rather wide input range and you could run your locos on e.g. any DCC layout wthout precautions. Space left over is enough in my eyes.

Last edited on Thu Feb 26th, 2015 08:52 am by Helmut

Bernd
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Helmut wrote:
Alas only the hobby's dinosaurs ( like me ) seem to dare to tackle the mechanics to fit their desires. I even put in a 3v motor where appropriate. Those 3...6v can motors ( not to be taken for instrument motors, mind you ) of nowadays are a lot more effective than the open-frame 12V ones they still put in the models.

The only reason hobby dinosaurs do that is that they know how, have the tools and want to do it to get a better running engine. To me that's part of the fun in the hobby. To others it's just a lot of work they would rather not deal with. So be it. It was just a suggestion.

@Bernd
Why don't you put in a step-down converter 0f 0.5A rating, same size as the 78xx series? They have a rather wide input range and you could run your locos on e.g. any DCC layout wthout precautions. Space left over is enough in my eyes.


Those engines were modified many years ago, long before you even signed up. I discovered the Deltang receivers. The next generation of this set up will have a circuit board designed and use SMD. I just have a few other projects ahead of this to finish first.

Bernd

Herb Kephart
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''The only reason hobby dinosaurs do that is that they know how, have the tools and want to do it to get a better running engine. To me that's part of the fun in the hobby. To others it's just a lot of work they would rather not deal with. So be it. It was just a suggestion.''

And there you have it in a nutshell. Back in the day, a friend had a  prewar (that's pre WW2 folks) Mantua 0-4-0 camelback with a 3 pole 6 volt motor. Six volts was standard for HO back then. His son had put it on the layout to see how fast it would go on 12 volts, and toasted the windings. Asked if I could rewind it for twelve volts. I did. Took three or four tries, but I got it to work. ''Formula'' back then was three wires sizes smaller for twice the voltage. At that time I only had very basic hobby tools

Of course, this was an old style open frame motor, which incidentally can be made to operate much better with an armature balance job, and reduction of brush tension. The idea is to push the limits of your ''comfort zone'' Pick up a $5 loco at a show and dive into it. If you make a mess of getting it to run, go find another 5 buck special. You won't have a big investment, Iif you find that swapping motors isn't for you it's OK, but TRY.--You might just surprise yourself. Remember that there are always people out there with less ability than you have.


Herb--the happy

W C Greene
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Oh goodness, this opens a can of ancient worms! Alas, today's model railroader wants (needs) to open the green box and run his/hers new loco. Of course there's a 28 page manual about programming, CV's, this & that which needs to be memorized before the new loco will turn a wheel. Such a shame that we can't just turn on the transmitter, then the loco, and RUN the freaking loco! Now, I gotta get after that Tyrannosaur before lunch....Later Gator..

Woodie

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I have been putting radio control into 009 locos and yes I do change the motors if necessary (ie if they are old and inefficient). I think this is partly because you have to build locos, usually from kits, in 009, as RTR is pretty sparse, although it is coming along now. So you get used to fiddling with the works and also you can build a kit to suit the radio and battery gear.

I'm starting into 3mm scale (100:1) standard gauge now.... You have to build those too.

Frank

Bernd
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And there you have it folks. Three dinosaurs with the same thinking.

But, and there always is one, there are modelers out there who all they want to do is operate the trains in a most realistic fashion. This opens a niche market for the guys that can fix things like installing motors, etc. There's lots of MMTB modelers out their.

For you folks in Rio Linda, MMTB is More Money Than Brains. ;) :bg: :)

Have a nice day.:Salute:

Bernd

 

Si.
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Hi Herb.

I think the axle-hole in your flagstone is a bit off...

...chip more away on the bottom right.

Si.

Tramcar Trev
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Last edited on Fri Feb 27th, 2015 04:21 am by Tramcar Trev

Tramcar Trev
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Herb you never cease to amaze me....

mwiz64
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Changing to a hotter wind motor is a great idea. Just keep this in mind. Volts x Amps = Watts. Watts are what does the work. So if your current 12v train draws 1 amp to do its work then it's using 12 watts to do the work 12x1=12... Right? Now switch out to a 6v motor... You still need 12 watts to move the train but it's going to take twice the current. 6x2=12. What does that mean? Well if all else is equal the 6v motor is running your battery dead twice as fast. Right, we halved the voltage so had to double the current to do the same amount of work.

I still think this is a great solution. I just wanted everyone to understand what's going on.

A guy like Bernd probably increases the gear ratio thereby lightening the load on the system and R educing the current draw. This will cause the train to run slower but thats likely OK. Most engines run too fast anyway. And now we've come full circle. Are you guys sure the loco won't perform well enough with a lower voltage and no motor change? You might just try that first and see. You could be surprised....

Herb Kephart
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Si

Don't judge that wheel until it's finished. It is being chiseled to NMRA* standards of the day 

* National Mesozoic Railroad Assn.



Herb

Helmut
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@mwiz
Your reasoning only holds true if you assume that there is no poor gearing, nor sloppy bearings, and a motor that is equally effective as a can motor. Only then you need e.g. 12Watts in any case. Therefore I said: " tackle the mechanics", because there lie endless possibilities of improvement. As an example, that R/C switcher I've shown:
http://freerails.com/view_post.php?post_id=57971
originally used 150mA@12V at full slip.
After improving the axle bearings, and changing the drive train it uses 54mA@3V. Pulling power has even slightly increased due to the absence of motor-induced vibration.


Last edited on Fri Feb 27th, 2015 02:36 pm by Helmut


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