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Super Modulator
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Danger!

What track voltage you running? You will use a lot of wattage... watts is volts times amps... if you were running 24 volts on the track, and wanted to drop the voltage to 12 volts at 2 amps, you are dissipating 24 watts! That's a lot of heat.

You could not use a voltage regulator... either a switching power supply or a big resistor... V=IR, so 12 = 2*R or the resistor would be 6 ohms and about 50 watts (a 24 watt resistor running at 24 watts would burn you and melt plastic)...

I doubt seriously that there is any chance that the Bachmann "electronics" would do this for you. The easiest solution is a big resistor, and REMEMBER, there will still be 24 watts of heat produced... (again assuming 24 volts on the rails).

Regards, Greg
 

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Posted By Johnn on 29 Jan 2010 09:57 PM
DCS seems to be far and above all other systems including Battery, Sorry just the way i see it. A freind of mine just received a Quote from a local RCS dealer and well 1500.00 per loco is insane ? Just goes to show dont always beleive whats advertised above? I'l stick with track power. Seems to be the Best way to get my train fix.



What exactly was that quote for?

What sort of loco?
Did it include sound? If so which brand of sound?
 

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Super Modulator
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Jeeze, this thread is about the harbor models smoke unit, not if RCS installs are too expensive or if DCS is better than something else...

Manfred, what track voltage are you running? See my post 2 back for info.

Regards, Greg
 

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The best smoke unit on the market is?

Chuck - watching your video, it looks like the smoke output is 10 or 15 degrees behind the valve events at front and back dead center. Clearly you should dump those systems and move to DCC...

Ok, just kidding.

But good work, you locomotive works fabulously well.
 

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I am using the elite power pack its 21 volts,i guess!

Manfred Diel
 

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Thoughts.......
I am using the revo to control the K27 ,the smokeboard/on/off..not much volume control, so what..............?
i am using a second revo reciever with the non plug and play adaptor and use it to turn the smoke on +off and in between control the smoke output!
First ,wire into the harbor unit a bridge rectifier (so it smokes in forward and (reverse(polarity)
then i set the least smoke out put(starting voltage) next the most smoke output(12volt)
next reduce the full speed to watever % above value given
then MU the 2nd rec to the 1rst and ......a kind of smoke output which matches the speed of the loco(would be nice to incorporate the piston slap)

Manfred Diel
 

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Super Modulator
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good idea, although not sure what the pwm output of the revo will do to the smoke unit...

I have no clue what electronics are in that board, but certain electronics will see the pwm output at 21 volts.

have you experimented yet? what do the specs say about max voltage? have you seen the electronics? is there a microprocessor?

Regards, Greg
 

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Electronics? The whole case is sealed shut ,the only thing you see on electronics is an automotive fuse,some wire and a fan even looking inside the smokeunit with a small dental mirror does not reveal a thing!! So i guess i try my luck and hook everthing up in the K27.I not to much worried becouse the bench test worked great so hope fully on saturday at the train convention at south town expo in Sandy(UT) my fellow club members see the urge for a prolonged test to serve the MLS community,hee!

Manfred Diel

Bevor i forget ,Greg, the distributor of the unit mentioned in the manual some kind of speed control would work to regulate the output of the smoke but if run in reverse the heating element would burn out in a snap(thats taken care of with the install of a bridge rectifier(or diodes)

On the other hand...is there a easy electronic wich converts PWM to an flat non pulsed power??
 

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I bought the Lionel smoke unit mentioned earlier in this thread. Just received it yesterday and am very pleased, however no wiring instructions were included. Being as how Lionel is AC and not DC I don't want to burn this unit up wiring it incorrectly. It looks very similar to TA Studios Turbo smoke unit except it has a 4 pin plug whereas the TA unit has a 3 pin plug.
Anybody know how to wire this thing?
Thanks
Bill Nesbitt
 

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Super Modulator
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Could have a small FW bridge on it (which is probably why you asked for pictures).

Yep a full on high res picture of the circuit board would be helpful.

Regards, Greg
 

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It can be run from at least 2-3 LM7812 regulators in parallel. Use the 1 amp or higher versions, they also make low power units which would smoke under that load.
Since they would be putting off lots of heat, a decent heat sink and possibly a fan should be able to keep em cool. The regulators have built in over-temp shutdown as well, so if they start cutting in and out they are running too hot.

JP
 

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Super Modulator
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Yep, they will make heat. One downside of paralleling regulators, is if one shuts down, the other 2 would overload. My experience has been that the shutdown does not work great and usually you get melted plastic regulator as a result. (don't ask me how I know!)

Regards, Greg
 

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Ah, releasing the built-in smoke, i have partaken in some electronics smoking as well.

Which ever way it is done, any kind of linear regulation scheme will have ~24 watts of heat which will need to be cooled. Possibly need a blower or other means of lots of air flowing over the components to keep plastic from melting.

JP
 

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Hello all,

Thanks for the response. I was very busy yesterday, but I will take some pictures today and try to put them on here.
I've never posted photos here, or anywhere, B-4 before so I may need some help. As it's 7:30 am here it will be a few hours.
Thanks for your help.

Bill Nesbitt
 

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Super Modulator
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Since you are not a 1st class member, you need to get the pictures up on the internet somehow... if that is a pain, email them to me.

Regards, Greg
 

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Super Modulator
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Mike, they do not appear to be the same unit, they are not physically the same, and the connections are different. The TAS has a logic level input (that you pull to ground) to run the fan, plus a jumper selectable diesel mode.

The Lionel unit has a 4 pin plug, and probably "direct drive" to the fan motor like the MTH unit does.

Regards, Greg
 

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--

Here is a schematic I drew from your verbal circuit description, voltage regulator not shown. Is this correct? I suspect that it is not but hopefully is close. From my reading about the LM3914 only one FET would be one at a time in dot mode and one or more in bar mode proportional to the voltage. (The datasheet I found did not elaborate.)

The amount of current thru the smoke unit would be a function of the value of the resistors so in dot mode only one resistor would be conducting. As the motor voltage goes up the next FET would turn on and previous one would turn off. The corresponding resistor value should be lower to allow more current to flow thru the smoker.

If I understand this circuit and IC correctly then if bar mode was used the same value resistor could be used and as more FET get turned on the resistors would be in parallel and the total resistance would decrease allowing more current to flow, thus more smoke to be generated.



Regarding the FETs, would they turn off on their own as the motor voltage drops or are pull down resistors needed on the gates?

I'm not an EE, but I am a ham so I have a little understanding of electronics. Correct me where I'm wrong and I'll fix he diagram. I have an application for a similar circuit so that has caught my interest. I just want to turn on a couple of LED's (headlights for a rail car) when a certain motor voltage is reached or exceeded and off when it drops below that level.
 
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