Author Topic: Shorting out  (Read 20149 times)

TwinStar

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Re: Shorting out
« Reply #15 on: November 12, 2018, 11:26:19 AM »
A piece of plexiglass affixed over the whole terminal end of the enclosure?



I mention this as while tape or no cover at all might be fine for home, knowing Jacob is into Free-mo then if he's at a meet then I'd caution that the meet might becomes a workplace under some sort of law and the terminals would need to be covered properly.


- Tim

I build 'booster boxes' out of plastic Home Depot/Ace/etc style 16-19" tool boxes. They have a floor of 1/2" Baltic Birch with a Mean Well power supply and a Digitrax DB150 mounted inside. I have two sets of Anderson Power Pole plugs with DC on one side and DCC on the other so that I can power DC at home and be Digitrax compliant at a Free-mo setup. I have a a 92X25MM AC axial fan and vents built into the box to provide cooling.

These are used with the lid latched closed (ventilation described above) so I would imagine a simpler cover would suffice. I can attach an exterior label requiring AC power to be removed before opening as well.
Jacob Damron
Modeling late 1950's Dallas Union Terminal in Free-mo+ modules

Texas Railway Modeling and Historical Society trmhs.org
trmhs.org

G8B4Life

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Re: Shorting out
« Reply #16 on: November 13, 2018, 06:50:43 AM »
That's an interesting factoid about the hole diameter and RF wavelength Alan. Another tidbit of knowledge to tuck away.

My SMPS, and the one I used for the charging station at work don't have holes but slots, just like your MeanWell for the accessory bus (mine is the same style as yours but different model NES instead of SE, they were a good deal at the time). I wonder if I should read the specs for any derating, the one at work I mounted upside down under a shelf; it's still horizontal just upside down.

It sounds like you've got everything covered Jacob. Being inside the portable power distributor "toolbox" you probably do only need something simple to prevent something accidentally bridging the mains terminals. I'm surprised that the supplies didn't come with a clear plastic clip-strip for that purpose.

- Tim

TwinStar

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Re: Shorting out
« Reply #17 on: November 13, 2018, 08:41:54 AM »


It sounds like you've got everything covered Jacob. Being inside the portable power distributor "toolbox" you probably do only need something simple to prevent something accidentally bridging the mains terminals. I'm surprised that the supplies didn't come with a clear plastic clip-strip for that purpose.

- Tim

I was surprised too but I imagine the target market for these is someone with enough electrical experience to know how to build a proper cover.
Jacob Damron
Modeling late 1950's Dallas Union Terminal in Free-mo+ modules

Texas Railway Modeling and Historical Society trmhs.org
trmhs.org

TwinStar

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Re: Shorting out
« Reply #18 on: November 13, 2018, 08:43:30 AM »

Mount horizontal and provide ventilation.

IIRC the PWR-56 requires a horizontal mount as well. I have to assume this is significant.
Jacob Damron
Modeling late 1950's Dallas Union Terminal in Free-mo+ modules

Texas Railway Modeling and Historical Society trmhs.org
trmhs.org

mecmt

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Re: Shorting out
« Reply #19 on: November 13, 2018, 05:48:58 PM »
If I was to get a power pack like the one in the post which one should I get.  I am unsure on the amp.

Alan

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Re: Shorting out
« Reply #20 on: November 13, 2018, 07:28:45 PM »
That question is not as easy to answer as one would imagine. Do you own or have access to a multimeter?

Here is the dilemma. With a power supply too small you will have the same problem you have now. With a power supply too large you run the risk of melting things or even starting a fire if there is a short circuit like from a derailed locomotive. Additionally, your track length, joiner integrity, frequency and length of feeder wires, bus wire length and gauge, and future expansion plans factor into the answer.

You perhaps have read a lot of forum discussions about wire size for bus and feeders. Too often the advice given is based on how much current is needed to operate trains. Better advice is based on the buss and feeders' ability to pass 100% of available power supply current with minimal voltage drop. This approach assures the power supply over-current protection will operate as designed in the event of a short circuit. So, the question that should be asked is how large of a power supply will my wiring arrangement safely permit, not how much power do my trains need. Hence why I ask if you have a multimeter. With a few measurements on your layout we can give you a good and safe answer before you buy a power supply.
Alan

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When I was a kid... no wait, I still do that. HO, 28x32, double deck, 1969, RailPro