Layout current draw

[train18393]

I have 2 DB150s with power supplies, so I have 5 amps available in each district of my two districts. It is also set up in districts due to length of runs. It is possible (although not likely) to have four 4 unit consists with two sound B units, un-powered and 2 powered un-sounded (is that a word?) A units, as well as several powered and sound equipped switchers, either steam or diesel. I have about 20 lighted passanger cars, with incandesant bulbs. There are times when I have had most of these running in one district, and I have never over loaded the 5 amps of the district. I have room for 5 engineers, so  a large percentage of these locomotives may be running at any one time, sometimes an engine set or more may be idle in the locomotive facility, or in the roundhouse, but the sound is generally turned down, not off in that case.

I have never measured the current draw, as I don't have a meter that will measure DCC current. I do not think a normal ammeter, which is usually calibrated to be accurate when measuring  60 HZ, is accurate. I know a voltmeter is not accurate measure. They are both good relative measuring devices for the price, but they are not an accurate indicator of DCC volts or amps.  

 Paul

Dayton and Mad River RR

[Texas Zepher]

I have 15A spread across 3  - 5A DCC boosters.

Wow, what all are you running to pull 15A?  

I have close to 50 locomotives and 12 of them are sound locomotives. ...  I planned for growth and the future.

Ah I see. 15A is what is available not what is actually being used.  In that context The Platte Valley & Western has  8 -  5A power stations for 40A.  I would guess that even at the highest peak usage it has ever actually only drawn 8.  There is an old ABBA set of Athearn blue box PA units that pull 2 amps all by themselves.   But the locomotive facilities are also on power switches so one or all the storage tracks and be cut off from power when not in use.

[jbinkley60]

I have 15A spread across 3  - 5A DCC boosters.

Wow, what all are you running to pull 15A?  

I needed two because I wanted to place the second booster closer to the districts it serves and not run larger longer bus feeds.  I have close to 50 locomotives and 12 of them are sound locomotives.  I suspect any new locomotives will have sound.  I also wanted 2 - 5A booster for the dual mainline, so the third really ends up covering most of the yards and sidings.  I can easily add a fourth, if ever needed.  Simply move one pair of wires to 1/2 of a PS4 to a new booster and off an existing one.  I planned for growth and the future.

 

 

[Texas Zepher]

I have 15A spread across 3  - 5A DCC boosters.

Wow, what all are you running to pull 15A?  

[simon1966]

I have 7.5amps split between a Zephyr and a DB150 booster.  I only got the DB150 because I was able to get an Empire builder set off e-bay for what a new DT400 throttle was going to cost.  I have tried, but never actually overloaded my Zephyr.  I have had 8 sound locos running at once in the Z's power district. 

[cacole]

A regular ammeter and AC voltmeter, especially the analog type, don't give you an accurate reading because they can't respond fast enough to the high frequency square-wave DCC signal's pulses.  What they will give you is an average that is close enough as long as you're not right on the threshhold of a current overload.

[jbinkley60]

  I've been reading alot about power supplies for DCC layouts, districting and such and wondering if I needed more power.  So I installed an amp and volt meter (AC for DCC) the other night and was a bit surprised the "idle" current draw was 2/3 of an amp. at 14.4 volts.  Of course I did have 35 decoder equiped locos on the layout at the time.  All the locos were "off" including sound.

  To test things out, I fired up most of the locos including sound and lights.  This brought the draw up to 1.05 amps with nothing moving.  Running a couple of locos ran the draw up to 1.25 amps, same voltage.  These were newer can type motors.  I then shut the locos down and removed them one by one, watching the effect on the system.  With all locos off the rails I was able to get the draw down to .01 amps at 14.7 volts.

  It was interesting to see how much "usable " power was available.  Basically you could run three or four locos under load for what the idling engines take up.  Even so, with a "basic" 3 to 5 amp power supply, you could still run several double headed trains and not run out of power.  I would think this would cover most normal home layouts.  However if you are operating switches and lighting off the same system you would need some type of power augmentation for reliable operation.

  How much power do you have on your layouts?

Tilden

I have 15A spread across 3  - 5A DCC boosters.

 

 

 

[Don Gibson]

 Safety valve:

My ABBA F unit set uses about 3 amps when running. That is the biggest single power event on the system.

Current ABBA offerings (Genesis, Stewart, InterMountain, Proto 1000) should be using only @1 amp total,  or (.25a per) under normal circumstances. Add to that Sound, or DCC module draw,

Your meters may be giving you inaccurate readings.

4 old Athearn BB ABBA engines might draw  3a.

 

[Don Gibson]

Tilden:

I'm not sure regular voltmeters and ammeters will read DCC square-waves or Pulse-Width-Modulation accurately - with or without re-calibration.

What say you Randy ?

[lvanhen]

I haven't put a meter on my stuff, but with a Prodigy Advance (3amp/15v output) I have run 4 sound locos (Atherrn Challenger, Lionel Turbine, 2 Atlas diesels + 1 Atlas non-sound diesel) and 3 Walthers lighted(DC) & 3 Bachmann Spectrum lighted(DC) passenger cars, without problems (all this on a double loop 4x8!)!  Switch motors & other lighting is from old DC packs.  You'd have to be way beyond a 1 man operation to need boosters!

[Don Gibson]

 

How much power do you have on your layouts? 

Layout: 2.5 amps DC  Cab A; 1.5 amps DC  Cab B.

Test bench: 0-3a 0-18v Regulated Lab. supply

Accessories: 5v, 24v, +12v -12v 10amp max. Switching supply

I FIND lighting buildings consumes the amperage. Old Engines (Athearn) .5a - .75a each, new engines .2a-.4a ea.; Twin coil machines 1.25a-3a each, 3v - 12v geared Stall motor machines - imperceptable.

Cab A is for diesels (multiple lashups). Cab B is for Steam (no double heading).

RF control + Analog sound (via rail) +Sub Woofer.

[Anonymous]

This is all true . . . as far as it goes.  

BUT,

If you run sound-equipped locomotives, or some types of lighted passenger cars, there will be an invisible "spike" at power-on, and after a circuit breaker trip (whether in the booster or external breakers like PowerShields) to charge up the capacitors.   

So it may appear that you're within the limits of your power supply, but have the breakers or command station trip repeatedly anyway, with the only solution being to remove some of those sound engines from the layout, power it up, then replace the engines one by one. 

Things will run fine for a while, then a derailment will occur, and the booster just keeps tripping.  Again.  No, you're not crazy, and no, your layout is not haunted.  You just can't see the spike on a meter.

 

 

 

[jrbernier]

Tilen,

  I have 10 amps of power(Digitrax command station and a booster).  I do NOT use DCC track power for other stuff like building lights or switch machines.  An old power pack can be used for those functions.  The DCC power is too expensive for simple lighting projects around the layout.

  The Ring Engineering EOT device web site does not give any current draw info, but I would expect it to be quite low.  You would need a motor device to draw measureable current.  BTW, if you used a standard meter, you may not get a true reading.  Most VOM's are configured for 60 Hertz current.  The RRampMeter will measure this higher cycle current.  Check out Tonys Trains for more info on this meter.

Jim

 

 

[Tilden]

  I was wondering how much those new EOT devices that fit in the truck and run off track current would draw.  I'm not sure if I've see any info on that.

Tilden 

[Texas Zepher]

How much power do you have on your layouts?

I know I have a lot more than needed, so never even been curious to find out.   I did however do a study to find out what adding one resistor wheel set to each cars for signaling purposes would do.  It was calculated that the freight cars just sitting in the main yard would draw 2 amps.   The new plan is that only 1 in 5 cars will have a conducting wheel set.

[Anonymous]

I have too much availible at this time. I can go as high as 8 amps and then run more boosters to 20 amps max.

My ABBA F unit set uses about 3 amps when running. That is the biggest single power event on the system.

I have seen the Digitrax Zephyr run relatively big railroads in person.

[Anonymous]

  I've been reading alot about power supplies for DCC layouts, districting and such and wondering if I needed more power.  So I installed an amp and volt meter (AC for DCC) the other night and was a bit surprised the "idle" current draw was 2/3 of an amp. at 14.4 volts.  Of course I did have 35 decoder equiped locos on the layout at the time.  All the locos were "off" including sound.

  To test things out, I fired up most of the locos including sound and lights.  This brought the draw up to 1.05 amps with nothing moving.  Running a couple of locos ran the draw up to 1.25 amps, same voltage.  These were newer can type motors.  I then shut the locos down and removed them one by one, watching the effect on the system.  With all locos off the rails I was able to get the draw down to .01 amps at 14.7 volts.

  It was interesting to see how much "usable " power was available.  Basically you could run three or four locos under load for what the idling engines take up.  Even so, with a "basic" 3 to 5 amp power supply, you could still run several double headed trains and not run out of power.  I would think this would cover most normal home layouts.  However if you are operating switches and lighting off the same system you would need some type of power augmentation for reliable operation.

  How much power do you have on your layouts?

Tilden

I posted my results a while back (found this on page 20):

http://www.trains.com/trccs/forums/1016761/ShowPost.aspx

Since I run small steam; my "typical" loco with sound only draws 0.05 to 0.10 amps.

 

[Tilden]

  I've been reading alot about power supplies for DCC layouts, districting and such and wondering if I needed more power.  So I installed an amp and volt meter (AC for DCC) the other night and was a bit surprised the "idle" current draw was 2/3 of an amp. at 14.4 volts.  Of course I did have 35 decoder equiped locos on the layout at the time.  All the locos were "off" including sound.

  To test things out, I fired up most of the locos including sound and lights.  This brought the draw up to 1.05 amps with nothing moving.  Running a couple of locos ran the draw up to 1.25 amps, same voltage.  These were newer can type motors.  I then shut the locos down and removed them one by one, watching the effect on the system.  With all locos off the rails I was able to get the draw down to .01 amps at 14.7 volts.

  It was interesting to see how much "usable " power was available.  Basically you could run three or four locos under load for what the idling engines take up.  Even so, with a "basic" 3 to 5 amp power supply, you could still run several double headed trains and not run out of power.  I would think this would cover most normal home layouts.  However if you are operating switches and lighting off the same system you would need some type of power augmentation for reliable operation.

  How much power do you have on your layouts?

Tilden