Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

DCC powered light

12755 views
63 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    December 2007
  • From: Gateway City
  • 1,593 posts
DCC powered light
Posted by yankee flyer on Saturday, February 2, 2008 9:29 AM

Hello Guys

Bear with me on this please.

I had a cheap MOW car that had a search light type, work light on it. It drew power from the track. I had bought a Digitrax Zephyr to run my system but could never  get it to work properly. I had other issues with the Zephyr but I don,t want to get into that whole issue.

My question is, what kind of power would the light need  and would it effect the dcc system? My NCE power cab had no trouble with it. And please NO brand fighting.                   

Lee                                                         

  • Member since
    July 2003
  • From: Metro East St. Louis
  • 5,743 posts
Posted by simon1966 on Saturday, February 2, 2008 9:54 AM

If it works with the Power Cab and you have "no trouble with it" what is the question?

If if draws power from the track then it should just run continuously on a DCC powered track.  All it will do is suck some amperage and potentially reduce the number of locos you can run. It all depends on the current draw.  If you want you can probably install a cheap decoder and control the on/off of the device.

Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 19,815 posts
Posted by MisterBeasley on Saturday, February 2, 2008 10:23 AM

If you put it on your DCC rails, it will get full voltage, all of the time.  That's likely to burn out the light bulb pretty quickly.  You could add a decoder, as suggested, but that seems like a lot of expense for an accessory car like this.

I would try out the light with a couple of different resistors, to cut the voltage to the bulb down a bit.  Once you've got the right one, you can solder the resistor into the circuit, maybe under the car frame where it won't be seen, or paint it to look like an "auxiliary brake cylinder."  I've found some very small slide switches (I think Minitronics make them) to use in situations like this, too.  They can be mounted under the car and used to manually turn the light on and off.  Yet another option is a latching magnetic reed switch that you can activate with a "magic wand."

It takes an iron man to play with a toy iron horse. 

  • Member since
    December 2007
  • From: Gateway City
  • 1,593 posts
Posted by yankee flyer on Saturday, February 2, 2008 10:29 AM

Thanks

Simon

The question was what  are the power requirments? 12v, 6v or what kind of bulbs would normally come in a model car. Are the DC lights differant from DCC? I'm just trying to learn.

appreeeeeeciate it.

Lee 

  • Member since
    October 2004
  • From: Colorful Colorado
  • 8,639 posts
Posted by Texas Zepher on Saturday, February 2, 2008 10:35 AM

 yankee flyer wrote:
The question was what  are the power requirments? 12v, 6v or what kind of bulbs would normally come in a model car.
Ah, normally that sort of thing has 12-18V bulbs. 

Are the DC lights differant from DCC?
No a filament light bulb is the same regardless of how it is powered.   The main difference is that DCC has constant power to the track while DC varies from zero to max (usually about 15V).  On DC the bulb will shine brighter as the train goes faster.  With DCC it will shine a maximum brightness all the time.  That is why it will burn out much quicker.

Personally I think replacing it with one of the ultra bright LEDs would be way cool. 

  • Member since
    December 2007
  • From: Gateway City
  • 1,593 posts
Posted by yankee flyer on Saturday, February 2, 2008 12:13 PM

This forum is great.

 

changing to an LED would be a very good first project of that sort I appreciate the suggestions.

Lee

Moderator
  • Member since
    June 2003
  • From: Northeast OH
  • 15,879 posts
Posted by tstage on Saturday, February 2, 2008 12:59 PM
 yankee flyer wrote:

This forum is great.

 

changing to an LED would be a very good first project of that sort I appreciate the suggestions.

Lee

And don't forget your resistor...Smile [:)]

Tom 

https://tstage9.wixsite.com/nyc-modeling

Time...It marches on...without ever turning around to see if anyone is even keeping in step.

  • Member since
    January 2007
  • From: Eastern Shore Virginia
  • 3,290 posts
Posted by gandydancer19 on Sunday, February 10, 2008 1:40 PM
 tstage wrote:
 yankee flyer wrote:

This forum is great.

changing to an LED would be a very good first project of that sort I appreciate the suggestions.

Lee

And don't forget your resistor...Smile [:)]

Tom 

You may also want to put a diode in series with the resistor and LED too.  LED's are not meant to be rectifiers, but they will do OK for a while.  A 1N4001 will work.  Connect it cathode-to-anode of your LED.  It is not going to mater which lead goes to what rail as the track is now AC with your DCC system.

Elmer.

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

  • Member since
    February 2006
  • From: Gahanna, Ohio
  • 1,987 posts
Posted by jbinkley60 on Sunday, February 10, 2008 6:25 PM

 

I really wish folks would stop saying that DCC is AC.  In certain contexts it can be very misleading.

 

Engineer Jeff NS Nut
Visit my layout at: http://www.thebinks.com/trains/

  • Member since
    September 2007
  • From: Charlotte, NC
  • 6,099 posts
Posted by Phoebe Vet on Sunday, February 10, 2008 7:18 PM
 jbinkley60 wrote:

 

I really wish folks would stop saying that DCC is AC.  In certain contexts it can be very misleading.

 

The shape of the wave is irrelevant.  When current flow alternates between positive and negative, that's AC.  Why, what do you call it?

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    January 2008
  • From: Central Georgia
  • 921 posts
Posted by Johnnny_reb on Monday, February 11, 2008 7:52 AM
 Phoebe Vet wrote:
 jbinkley60 wrote:

 

I really wish folks would stop saying that DCC is AC.  In certain contexts it can be very misleading.

 

The shape of the wave is irrelevant.  When current flow alternates between positive and negative, that's AC.  Why, what do you call it?

Holy cow you mean that DCC is "AC"? I have just started reading up on DCC and already know that DCC is "AC" and that the "decoder" turns it back into "DC" before it sends it out to the motor or other accuracy's. It's no wonder that an "LED" meant for "DC" voltage is getting "HOT". This is "SO CONFUSING". Not!Dunce [D)]

Johnnny_reb Once a word is spoken it can not be unspoken!

My Train Page   My Photobucket Page   My YouTube Channel

  • Member since
    December 2007
  • From: Gateway City
  • 1,593 posts
Posted by yankee flyer on Monday, February 11, 2008 8:40 AM

Johnny_reb

You are not the only one confused, like I said my tech school was a long time ago (1956).

I was an Airforce tech, repairing radar that put out 5 million watts of power,and we did it with vacuum tubes. I haven't done anything technical since 1960. I bought an LED and tried it on a 12V  DC power supply, nothing, I tried it across the track and it lit up. It looks like I'm going to have to start "school" all over again. 

Lee

Wishing for, Blue Skys

 

  • Member since
    January 2008
  • From: Central Georgia
  • 921 posts
Posted by Johnnny_reb on Monday, February 11, 2008 9:33 AM
 yankee flyer wrote:

Johnny_reb

You are not the only one confused, like I said my tech school was a long time ago (1956).

I was an Airforce tech, repairing radar that put out 5 million watts of power,and we did it with vacuum tubes. I haven't done anything technical since 1960. I bought an LED and tried it on a 12V  DC power supply, nothing, I tried it across the track and it lit up. It looks like I'm going to have to start "school" all over again. 

Lee

Wishing for, Blue Skys

Lee, I am sorry if I have misled you, but I was not confused. I was being sarcastic.

An "LED", like all diodes only works one way. A bi-color diode is two diodes in one case. A tri-color diode is three diodes in one case, so on and so forth. 

Simply put a diode is a one way valve. In that it will let current pass only one way. So if you hookup the diode backwards it will not light. If this is the case just turn the diode (half-way) around and try it again.

As I do not make my living in electronics I will not try to explain the leads on an "LED". But all "Led's" that I know of use "DC" voltage. But will light up if hooked up to "AC" voltage because it changes polarity at 60 cycles a second, giving the "Led" the right polarity half of the time.

Now if one of the "electronic" guys will chime in here as they can explain it better then I.

 

Johnnny_reb Once a word is spoken it can not be unspoken!

My Train Page   My Photobucket Page   My YouTube Channel

  • Member since
    December 2004
  • From: Pa.
  • 3,153 posts
Posted by DigitalGriffin on Monday, February 11, 2008 10:03 AM

Let me guess, you have the popular Bachmann Silver MOW car with crane?  I have one too.  Big Smile [:D]

I believe it is a 12 Volt bulb.  If you put it on a DCC track (typically 13->15V aternating current) then you will drastically shorten the life.  I would see if you can put a resistor in there somehow.

~Don

 

 

Don - Specializing in layout DC->DCC conversions

Modeling C&O transition era and steel industries There's Nothing Like Big Steam!

  • Member since
    September 2007
  • From: Charlotte, NC
  • 6,099 posts
Posted by Phoebe Vet on Monday, February 11, 2008 11:37 AM

Johnnny_reb:

That description was perfect, except for the 60 cycle reference.  House current in the US is 60 cyycle, but AC describes alternating current at any cycle frequency.

 

Yankee Flyer:

I can speak vacume tube.  It's the same principle.  A diode has an anode and a cathode, just like a tube.  If you add screens like tubes use to control flow, then it becomes a transistor.  Flow is only one way.  Four diodes combined in a bridge can convert AC to DC.

All:

Becarefull hooking diodes up.  Like all solid state electronic deviced if they overheat, they will be destroyed.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    December 2007
  • From: Gateway City
  • 1,593 posts
Posted by yankee flyer on Monday, February 11, 2008 12:09 PM

Don

Actually my rail MOW is a Bachman, silver, with a cabin, tool chests and the "flood" light. But I was testing an LED. Talking about dumb, I knew LED stood for light emiting diode. I just was not thinking polarity.

Johnny_reb

I am getting really aggravated with these Atlas slide switches. the package says use AC current. I tried a toy train transformer at 8V to 12V AC and got melted motors. I tried a small 12V DC power supply and got melted motors.     Banged Head [banghead]         I think I'm going to rip out all the Atlas switches and replace with raido shack push buttons, one for each direction. It must be the switches. Also I am experimenting with an auto light bulb in series with the switch panel so I will know when current is flowing. That will tell me if a button is stuck. I did buy the resister and capacitor in the diagram you posted but I dont understand how it limits current flow.

Lee      Watching Freezing rain.

  • Member since
    February 2006
  • From: Gahanna, Ohio
  • 1,987 posts
Posted by jbinkley60 on Monday, February 11, 2008 8:26 PM
 Phoebe Vet wrote:
 jbinkley60 wrote:

 

I really wish folks would stop saying that DCC is AC.  In certain contexts it can be very misleading.

 

The shape of the wave is irrelevant.  When current flow alternates between positive and negative, that's AC.  Why, what do you call it?

AC generally refers to a continuous function signal that is a complete waveform that traverses from a positive signal voltage, crosses the 0 volage axis point, goes to a negative peak and then back to to 0 voltage axis point. 

DCC is a balanced DC differential pulse modulation system.  What this means is that each lead (or rail) is a DC pulse stream that is 180 degrees out of phase with each other.   Because they maintain this equal and opposite symmetry the DC component remains almost constant and thus can be rectified out to provide the power necessary to drive motors, lights etc.   There is no zero crossing point with regrads to a common reference point, only to each other.

You are welcome to call this AC, if you'd like.  It is just misleading in certain contexts and conversations.  DCC could have just as easily been a unbalanced unipolar,  not a differential design and there would be no zero crossing point.  A bipolar design would have a zero crossing point but no DC component.  The main reasons a differential scheme was chosen was to carry the DC component and to reduce noise.

 

Engineer Jeff NS Nut
Visit my layout at: http://www.thebinks.com/trains/

  • Member since
    June 2005
  • From: Hot'lanta, Gawga
  • 1,279 posts
Posted by Rotorranch on Monday, February 11, 2008 9:26 PM
 yankee flyer wrote:
Johnny_reb

I am getting really aggravated with these Atlas slide switches. the package says use AC current. I tried a toy train transformer at 8V to 12V AC and got melted motors. I tried a small 12V DC power supply and got melted motors.     Banged Head [banghead]         I think I'm going to rip out all the Atlas switches and replace with raido shack push buttons, one for each direction. It must be the switches. Also I am experimenting with an auto light bulb in series with the switch panel so I will know when current is flowing. That will tell me if a button is stuck. I did buy the resister and capacitor in the diagram you posted but I dont understand how it limits current flow.

Lee      Watching Freezing rain.

A switch is a switch. It has no idea if it's switching AC, DC, or DCC. It just opens and closes a circuit.

What motors are you melting? And which Atlas switches are you using?

Rotor

 Jake: How often does the train go by? Elwood: So often you won't even notice ...

  • Member since
    February 2007
  • 11 posts
Posted by JWBDolphins on Monday, February 11, 2008 10:20 PM

I too have a Bachmann MOW spotlight car and a DCC Zephyr.  It is nice that the light is on full brightness all the time, but I did wonder about the bulbs longevity.  I was also thinking about installing a mobile DCC decoder in it so that I could turn it on or off remotely and in fact went so far as to buy the decoder.

What I haven't had is the time to mess with it.  I've searched online to see if anyone has done this before and posted pictures/instructions - so far I've found nothing.  It did strike me that this might be massive overkill too!  Smile [:)]  But I like tinkering with things and will eventually give this a shot.

Has anyone done this and have any tips?  It looks like the MOW car has all-wheel pickup, which is good.   I figured I could hide the decoder in the cabin of the car.   My two other thoughts were 1) replacing the bulb with an LED or maybe 3 (again, has anyone done this already?).  The advantage of the DCC decoder is that it will take care of the current polarization for the LEDs.  Even if I don't replace the bulb, shouldn't the current rectifier that is built into the decoder reduce the current somewhat that goes to the bulb?, which will hopefully help it last longer.  And 2), the decoder I chose has 4 functions on it - I was thinking of putting a micro slide switch under the car so I could select which decoder function number would turn on or off the spotlight.  This way if I wanted to, I could set the decoder to the same number as one of my locos and have a selection of functions to choose from that wouldn't interfere with the loco.

If anyone has modified this MOW car, I'd be curious to know any tips or suggestions.  Maybe I'll take and post some pictures myself if I get around to this.

Back to the original poster's question - I think its been answered.  DCC will light the bulb at full power all the time - the bulb won't care which direction the DCC current is flowing.

  • Member since
    June 2005
  • From: Hot'lanta, Gawga
  • 1,279 posts
Posted by Rotorranch on Monday, February 11, 2008 10:41 PM
 JWBDolphins wrote:

I too have a Bachmann MOW spotlight car and a DCC Zephyr.  It is nice that the light is on full brightness all the time, but I did wonder about the bulbs longevity.  I was also thinking about installing a mobile DCC decoder in it so that I could turn it on or off remotely and in fact went so far as to buy the decoder.

What I haven't had is the time to mess with it.  I've searched online to see if anyone has done this before and posted pictures/instructions - so far I've found nothing.  It did strike me that this might be massive overkill too!  Smile [:)]  But I like tinkering with things and will eventually give this a shot.

Has anyone done this and have any tips?  It looks like the MOW car has all-wheel pickup, which is good.   I figured I could hide the decoder in the cabin of the car.   My two other thoughts were 1) replacing the bulb with an LED or maybe 3 (again, has anyone done this already?).  The advantage of the DCC decoder is that it will take care of the current polarization for the LEDs.  Even if I don't replace the bulb, shouldn't the current rectifier that is built into the decoder reduce the current somewhat that goes to the bulb?, which will hopefully help it last longer.  And 2), the decoder I chose has 4 functions on it - I was thinking of putting a micro slide switch under the car so I could select which decoder function number would turn on or off the spotlight.  This way if I wanted to, I could set the decoder to the same number as one of my locos and have a selection of functions to choose from that wouldn't interfere with the loco.

If anyone has modified this MOW car, I'd be curious to know any tips or suggestions.  Maybe I'll take and post some pictures myself if I get around to this.

Back to the original poster's question - I think its been answered.  DCC will light the bulb at full power all the time - the bulb won't care which direction the DCC current is flowing.

The answer to most of your questions is yes. With the decoder in the spotlight car, you wouldn't need a switch. The decoder would handle the switch. It wouldn't "interfere" with the loco, as all you will be using is the light circuit. You'd just need to set the function CV's as you want them.

The cabin would make a good place to hide the decoder.

One super white LED would make the light look like a carbon arc spot light. Should look great. One LED is all that will fit in the reflector correctly.

Rotor

 Jake: How often does the train go by? Elwood: So often you won't even notice ...

  • Member since
    January 2008
  • From: Central Georgia
  • 921 posts
Posted by Johnnny_reb on Tuesday, February 12, 2008 12:43 AM
 yankee flyer wrote:

Don

Actually my rail MOW is a Bachman, silver, with a cabin, tool chests and the "flood" light. But I was testing an LED. Talking about dumb, I knew LED stood for light emiting diode. I just was not thinking polarity.

Johnny_reb

I am getting really aggravated with these Atlas slide switches. the package says use AC current. I tried a toy train transformer at 8V to 12V AC and got melted motors. I tried a small 12V DC power supply and got melted motors.     Banged Head [banghead]         I think I'm going to rip out all the Atlas switches and replace with raido shack push buttons, one for each direction. It must be the switches. Also I am experimenting with an auto light bulb in series with the switch panel so I will know when current is flowing. That will tell me if a button is stuck. I did buy the resister and capacitor in the diagram you posted but I dont understand how it limits current flow.

Lee      Watching Freezing rain.

Lee, it does sound like your switches are sticking. Adding a light into the wiring will let you know if they are sticking. I myself plan to make all my turnout work with ground throws.

Just a thought here, does anyone else have access to your layout while you are at work? If so they may not understand how the switching system works.

Johnnny_reb Once a word is spoken it can not be unspoken!

My Train Page   My Photobucket Page   My YouTube Channel

  • Member since
    September 2007
  • From: Charlotte, NC
  • 6,099 posts
Posted by Phoebe Vet on Tuesday, February 12, 2008 5:51 AM

"could have just as easily been " is not the same as "is".

A wave that is first positive and then negative in polarity is an Alternating Current.  It is you who is playing confusing games with terminology.

I am aware that many digital signals are pulsing DC and that pulsing DC would not have permitted DC engines to reverse direction.  That is why they use zero stretching on one side of the alternating waveform to control the DC engine.  DC engines run slower on a DCC track because they are only getting half the voltage.  They get only the positive or only the negative for a long enough period of time for the engine to react.  The rest of the time, the direction of the current is reversing too fast for the motor to react, hence the annoying buzz.  I was doing digital signal analysis as far back as 1965.

Put an oscilloscope across the rails of your track and look at the signal.  It's square wave AC. It is ALTERNATING between positive and negative.

If you choose to call that positive DC and negative DC on the same signal, that's fine, but don't complain that others call it what it is.  The people calling it AC are not wrong.  Since electronic devises don't speak english, they will react to what they see.  And they see AC.

You know, like calling a man a "detainee" does not alter the fact that he is a "prisoner".  Changing the name does not change the facts.  I believe that you are confusing a description of the waveform (a variable timed square wave as opposed to a sine wave) with the AC vs DC argument.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    February 2006
  • From: Gahanna, Ohio
  • 1,987 posts
Posted by jbinkley60 on Tuesday, February 12, 2008 5:09 PM
 Phoebe Vet wrote:

"could have just as easily been " is not the same as "is".

A wave that is first positive and then negative in polarity is an Alternating Current.  It is you who is playing confusing games with terminology.

I am aware that many digital signals are pulsing DC and that pulsing DC would not have permitted DC engines to reverse direction.  That is why they use zero stretching on one side of the alternating waveform to control the DC engine.  DC engines run slower on a DCC track because they are only getting half the voltage.  They get only the positive or only the negative for a long enough period of time for the engine to react.  The rest of the time, the direction of the current is reversing too fast for the motor to react, hence the annoying buzz.  I was doing digital signal analysis as far back as 1965.

Put an oscilloscope across the rails of your track and look at the signal.  It's square wave AC. It is ALTERNATING between positive and negative.

If you choose to call that positive DC and negative DC on the same signal, that's fine, but don't complain that others call it what it is.  The people calling it AC are not wrong.  Since electronic devises don't speak english, they will react to what they see.  And they see AC.

You know, like calling a man a "detainee" does not alter the fact that he is a "prisoner".  Changing the name does not change the facts.  I believe that you are confusing a description of the waveform (a variable timed square wave as opposed to a sine wave) with the AC vs DC argument.

I am not going to get into a huge debate on this.  I have an oscilloscope and have looked at the pulses on each rail.  I also have an EE degree and have designed networks and digital transmission systems, including differential pulse systems like this. 

I did a little more digging today on the NMRA website.  Looking in RP9.1.2 section 2.3

http://www.nmra.org/standards/DCC/standards_rps/RP-912.pdf

the recommended practice shows that either unipolar or bipolar encoding is supported as long as the differential is maintained to keep the DC component constant.  If not, locomotives would speed up and slow down as the symmetry of the pulse stream changed since this would cause a fluctuation in the DC component.  I thought I had read previously in the NMRA specs that only unipolar was supported.  They are cheaper to manufacture but bipolar can generally be transmitted over a greater distance (all things being equal).

If you want to make the case that any system using bipolar encoding is AC that is fine.  They do have a zero crossing point, which is one characteristic of AC.  A unipolar system does not have a zero crossing point and instead maintains a supply and common voltage reference point that are 180 degrees out of phase but neither rail would ever cross zero. 

There isn't any way to know which method a DCC manufacturer is using without looking at the output on an oscilloscope. 

 

Engineer Jeff NS Nut
Visit my layout at: http://www.thebinks.com/trains/

  • Member since
    February 2007
  • 11 posts
Posted by JWBDolphins on Tuesday, February 12, 2008 5:29 PM

THANKS Rotor - eventually I'll give this a try and report back how easy/hard etc it was...

 

  • Member since
    December 2007
  • From: Gateway City
  • 1,593 posts
Posted by yankee flyer on Tuesday, February 12, 2008 6:40 PM

Johnny_reb and all who posted thanks.

As to your question, fortunately my train and honey do's are the only pressing items. I'm retired.

My MOW light car is on hold until I get the Atlas dual coil motor power fixed so that I don't burn up the motors.  Some of the meltdown may have occurred when I leaned over the panel to work.  But there has to be other causes - sticking switches or something.  I built the 12 volt power supply, but it won't throw two turnouts at a time.  Someone referred me to Tom Horn's capacitor discharge circuit.It's a 35 Volt pulse.  So I bought the parts, and that is my next project.  Some of my E-tech skills are trying to come back.  Back in the stone age I spent quite a bit of time in front of an oscilloscope, so I can visualize a square wave.  Is the DCC power 15 volts peak to peak, or 30?  How is a digital signal transmitted?

Lee    

 

  • Member since
    February 2006
  • From: Gahanna, Ohio
  • 1,987 posts
Posted by jbinkley60 on Tuesday, February 12, 2008 9:40 PM
 yankee flyer wrote:

Johnny_reb and all who posted thanks.

As to your question, fortunately my train and honey do's are the only pressing items. I'm retired.

My MOW light car is on hold until I get the Atlas dual coil motor power fixed so that I don't burn up the motors.  Some of the meltdown may have occurred when I leaned over the panel to work.  But there has to be other causes - sticking switches or something.  I built the 12 volt power supply, but it won't throw two turnouts at a time.  Someone referred me to Tom Horn's capacitor discharge circuit.It's a 35 Volt pulse.  So I bought the parts, and that is my next project.  Some of my E-tech skills are trying to come back.  Back in the stone age I spent quite a bit of time in front of an oscilloscope, so I can visualize a square wave.  Is the DCC power 15 volts peak to peak, or 30?  How is a digital signal transmitted?

Lee    

 

The absolute maximum is 22 volts.  The recommended voltages are:

N scale - 12v
HO/S/O scale - 15v
Large scale - 18v

Here's an oscope image of my HO scale DCC system output signal:

 

 

 

Engineer Jeff NS Nut
Visit my layout at: http://www.thebinks.com/trains/

  • Member since
    July 2006
  • From: Vail, AZ
  • 1,943 posts
Posted by Vail and Southwestern RR on Tuesday, February 12, 2008 10:21 PM

In DCC there is no reference, there are just the two rails.  Neither has a claim to being a 'zero' reference, they only change with respect to each other.  So there is nothing other than the differential signal.  I wouldn't call it AC, but in many respects (especially if you are hooking an LED to it) it is certainly more like AC than DC.  But I would say that Engineer Jeff's description is technically the most accurate.  (Of course also being an Engineer Jeff, that's an easy stance to take!)

 

Jeff But it's a dry heat!

  • Member since
    June 2005
  • From: Hot'lanta, Gawga
  • 1,279 posts
Posted by Rotorranch on Tuesday, February 12, 2008 10:37 PM

Yankee Flyer...you're burning switch macine motors?

Again, what Atlas control switches are you using?

It has to be something getting set on the switches, or using the wrong switch.

I've only cooked 2 switch machine motors that I can recall since 1964. OK...3, counting one that cooked on The Kid's N scale layout. One each AHM, Lifelike and Atlas.

Since then, I've had 2 bad control panel switches. One Atlas quit many years ago, and I lost a Lifelike switch a few weeks ago. They didn't lock on, just quit working, (open circuit). 

Rotor

 Jake: How often does the train go by? Elwood: So often you won't even notice ...

  • Member since
    September 2007
  • From: Charlotte, NC
  • 6,099 posts
Posted by Phoebe Vet on Wednesday, February 13, 2008 5:59 AM

From the dictionary:

Alternating current:  An alternating current (AC) is an electrical current whose magnitude and direction vary cyclically, as opposed to direct current, whose direction remains constant. The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy. However in certain applications different waveforms are used, such as triangular or square waves.

What is so difficult?

The direction of current flow changes cyclically.  It does not "RESEMBLE AC".  It is not "IN SOME WAYS SIMILAR TO AC", it IS AC.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    December 2007
  • From: Gateway City
  • 1,593 posts
Posted by yankee flyer on Wednesday, February 13, 2008 7:42 AM

Rotoranch Hello

Over the year that I have been MR ing I'm sure that at least four  have melted. I admit one or two have been my fault, leaning over the panel to reach something or possible laying something on them. I have taking a couple of the Atlas slide switches apart, they look perfect. Maybe they just don't rebound after being pushed? Anyway I was hoping to limit the power pulse to less than a second like atlas  reccomends. Up untill this point I have been using a Lionel transformer that I measured at 8V to15V AC output.

The circut I'm looking at is at http://www.awrr.com/cdsupply.html  by Fred Horne, anyone care to comment?

Happy railroading

Lee 

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!