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Reply to "circuit breaker protection..."

@Hp289 posted:


PSX1, GRJohn seems to like...  Have ya'll come to consensus which is "better" for our model train application?   I do not have the knowledge base to pick one.  And, the PSX, when it trips, how do I reset it?   On the airpax, why 5amp?  shouldn't I want a 7.5 or 10 amp?  



Money is one of the two key factors in the decision.  The PSX1 is more expensive than the Airpax breaker.  The old maxim "You get what you pay for" applies here.  If you'd like to go a little less expensive then use the recommended Airpax breaker, and check out @SteveH's recommended links to help you with it.

A I understand it the PSX1 can either reset itself when the excessive load (current) clears, or you can set it up to require that you push a button to reset it.  For the money it should have both options.  I believe as well that there's also an option to add a noisemaker that will alert you the instant it trips.

With either solution choosing the trip current is a fairly important task.  Since you're not worrying about protecting the transformer (because the ZW-L is supposed to protect itself, as mentioned above) you need to be concerned about the precise current that your train will draw when it's operating, considering the maximum current draw of the motor(s) in the locomotive(s), any other electronics in the locomotive(s), e.g. sound, any smoke units, and any lamps or LED's in the locomotive(s) or cars.

The easiest was to do this is to set up your entire train and run it temporarily without the PSX1 or Airpax breaker in place.  Let it warm up and measure the current it draws, via a Volt-Ohmmeter or a dedicate ammeter installed between the transformer connection going to the center rail, and the center rail.  Remember that your curves, and any grades you have, will affect max current so you might want to make your measurement when your train is passing over them.

The last step is to install the PSX1 or Airpax breaker in place of your ammeter.

What value Airpax do you buy?  One "slightly higher" than the your max current measurement.

This is not an issue with the PSX1.  It's adjustable, so you set it to trip "slightly higher" than your max current measurement.

Define slightly higher?  This is easy with the PSX1.  Take a guess on the low side and run the train.  If it trips too much for your taste adjust it upward slightly and try again.  Repeat if necessary.  Note: Be sure that you use a known good train on known good tracks.  If the train has short-circuit problems inside it, or between it and the track, then the PSX1 should be tripping at lower currents so that the electronics inside the train don't overheat and fry because of excessive current draw from the short circuit.

Easy? Definitely not the simplest thing to do.  Do you have an alternative?  Yes, put PTC's (little self-resetting solid-state circuit breakers) inside each locomotive and each car having lights, smoke, StationSounds, etc. within it.  @gunrunnerjohn has mentioned many times over recent years why this is the best solution, and that all equipment should come from the factory with these already inside.  I agree.  Why isn't it already done?  We're back to money again -- it costs a little more to do so.

Good luck.  In spite of being a relative newbie you can do it.

Mike

Last edited by Mellow Hudson Mike

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
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