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Super User 164 posts Gregory Latiak GLatiak Super User 164 posts
Gregory Latiak GLatiak

Been an interesting week running in my various sound locos now that I sorted out that cute problem with my programming track. I had bought the Railroad&Co Programmer module -- not that jmri wasn't doing the job, but for the run-in script feature. This allows you to setup a script that runs the loco in different directions and speeds for user-determined lengths of time.

So I was running in the last of the bunch -- a Proto2000 GP9 and it was in a lengthy high speed run segment. Sitting in the yard were five other sound units in various states of audible inactivity. Abruptly it stopped and the fault light lit up for the yard. When I started lifting locos from the track the fault cleared... hmmmm. 3amp short setting on my PM42 feeding this area. Wonder what I was asking it to supply?

I have a set of rollers that I use for loco testing -- allows a static position on a segment of track to be used for testing or run-in. Thanks, Micro-mark... they work really well as long as the flanges are inside the bearings. And when I originally built the layout I decided to install an RRAMP meter in the console so I could see how hard the Zephyr was working. Now that I have added a DCS100 for more power and capability, the Zephyr still feeds a segment of the layout -- and the meter is still in that power feed.

So I setup a test stand in the metered area and ran my various sound locos through their paces and observed their power demands. Interesting... At idle they all consumed between 0.1 and 0.22 amps. At maximum speed though the variation was impressive. My latest loco, a Rapido GMD-1 only consumed 0.26 amps at top speed. The GP9, on the other hand, used 0.6amps running flat out. A similar unit from another vendor took 0.29 amps doing the same thing. I have a couple of steamers -- they fell between these two extremes. And audio special effects made no difference.

What did I learn from this? One, the yard was probably pulling close to 2amps when it shutdown. I need to review how I am supplying it and split things up a bit -- as a bunch of units burbling away in the yard is going to be pretty normal. The other was that the peak power demands are substantial and vary wildly.

Glad I had the test setup -- made it easier to identify these issues. And glad I wired a meter into the feed. Need one on the other booster as well.

Gregory Latiak

Please read my blog
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rickwade Prolific poster (deceased) 6,447 posts
rickwade

Great information

Thanks for this posting as i found it very interesting.  I have a small layout powered with a Zephyr and often leave locos idle on the layout so this information can prove helpful.

Rick

img_4768.jpg 

The Richlawn Railroad Website - Featuring the L&N in HO  / MRH Blog  / MRM #123

Mt. 22: 37- 40
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PeterU Regular poster 213 posts
PeterU

JMRI has a script called

JMRI has a script called LocoTest.py. It would be easily to modify to provide for locomotive break-in.

 

Peter Ulvestad
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Brent Ciccone Brentglen MRH Author 980 posts
Brent Ciccone Brentglen

Lighted Cars

Watch out for lighted passenger cars, a train of lighted cars can draw significant amps, even the ones with LED's. I believe that the Rapido Canadian draws an amp or more with all the lights on in the cars.

 

Brent Ciccone

Calgary
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Larry of Z'ville Frequent poster 984 posts
Larry of Z'ville

I find a wide curret variation

For engine only testing, DC no sound, I see a wide variation in current draw.  Definitely with voltage, load and motor.  The idle current your seeing is the sound current draw, by definition, the motor is not drawing current. (It the decoder is putting a small voltage to the motor the current will be that voltage stall level until the motor starts to turn.)

The P2K GP9 probably will see around 0.9 amps at wheel slip at max power.  So additional load from cars, grade or track can increase the current budget required.  Motor variation, age and health are also factors in this consideration.

Probably the most interesting result of my tests is that not all old motors have high current draw, and not all recent motors have low current draw.  I know it sounds trite, but I was expecting a more predictable result.

 

So many trains, so little time,

Larry

check out my MRH blog: https://model-railroad-hobbyist.com/node/42408

 or my web site at http://www.llxlocomotives.com
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Virginian and Lake Erie Super User 9,231 posts
Virginian and Lake Erie

See how much 3 units draw

See how much 3 units draw pulling a long train, that might be something.

Rob in Texas

MRH Blog / Prep for an Operating Session / Delving Into the Past / The Club Blog / Youtube / etmrc.org
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BR GP30 2300 Super User 685 posts
BR GP30 2300

If ya ain`t makin Hoover Dam

If ya ain`t makin Hoover Dam struggle.......you ain`t doing it right

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