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Hello everyone,

I've followed prior threads on this general topic, but I wonder what the consensus is on what is "fast enough" response time in a circuit breaker in the context of a train layout running modern locomotives?  A few months ago I added 10-amp breakers and TVS's from Mouser, based on recommendations in a prior thread, to my layout's power because it was a costly nuisance replacing the 10-amp fast-blow fuses I had been using.

This past weekend when the powered unit of my brand-new Legacy E8s manifested its dead short, the breaker didn't kick so I rushed over and killed the power.  I hadn't had a layout short since I installed the breakers, so I was surprised at this.  Later, with nothing on the track, I purposely shorted the rails to see how long it would take the breaker to trip.  It took 3 seconds with my KW set to 18 volts, during which time my 10-amp ammeter was pegged.  I pulled out the breakers and put fuses back in, until I come up with something better.

Now, I can't decide between replacing my single KW with a 180-watt Powerhouse, which I've read in this forum has the fastest-acting breaker out there, or adding PowerShield PSX-AC to my KW.  If I go for the PSX-AC, can I use just one, wired into the common lead going to both loops, or do I need a separate one for each output of the KW?  I would appreciate any advice.  If it matters, I currently have each variable output of my KW attached to a fixed input of my TIU, and the common lead is jumpered at the TIU.

Thanks,

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Chuck, Barry, anyone...do we happen to have any forum sponsors who sell the PSX-1AC?  I've decided to go this route and I need to order two of them.  I thought I'd ask here before I start calling hobby shops on DCC Specialties' dealer list, because I would suspect that many of those dealers don't sell 3-rail trains and wouldn't have this unit in stock.

Last edited by RETINPA
romiller49 posted:

Personally, I would dump the KW and go with the 180 brick. Old transformers and new trains simply do not go together. 

Huh, that's funny. There are many of us here on this form that use the great classic transformers with newer equipment. Of course any transformer, new or old, must be in serviceable order and have protective equipment such as circuit breakers and TVS diodes between it and what is being powered.

In this case the original poster is not happy with the trip time of circuit breaker is currently being utilized. The recommendation for the PSX-1AC is perfectly fine. Other options would be other circuit breakers with quicker trip times such as those that are tricked by magnetic versus thermal means.

RETINPA posted:

Chuck, Barry, anyone...do we happen to have any forum sponsors who sell the PSX-1AC?  I've decided to go this route and I need to order two of them.  I thought I'd ask here before I start calling hobby shops on DCC Specialties' dealer list, because I would suspect that many of those dealers don't sell 3-rail trains and wouldn't have this unit in stock.

I bought mine at Traintek.

http://www.traintekllc.com/dcc...ail-circuit-breaker/

I think also Charles Ro has them...but their site is down right now.

 

bmoran4 posted:
romiller49 posted:

Personally, I would dump the KW and go with the 180 brick. Old transformers and new trains simply do not go together. 

Huh, that's funny. There are many of us here on this form that use the great classic transformers with newer equipment. Of course any transformer, new or old, must be in serviceable order and have protective equipment such as circuit breakers and TVS diodes between it and what is being powered.

In this case the original poster is not happy with the trip time of circuit breaker is currently being utilized. The recommendation for the PSX-1AC is perfectly fine. Other options would be other circuit breakers with quicker trip times such as those that are tricked by magnetic versus thermal means.

I understand completely. To each his own. Im just used to the immediate breaker response of the brick.

Joel,

Look at the charts for the breaker type that you using. The 3 seconds to trip sounds about right.

The work around is to use a lower amp rated breaker of that type. Like a 3,4, or 5 amp. Then, a short heats up the unit faster. The trip time would still be around a half second.

it's hard to find magnetic breakers for less than a PSX-AC.

When you consider the costs, a new modern brick or transformer is really not out of range or a couple of PSX-AC's.

Thanks to everyone for your replies.  Just to be clear, I don't have a LOT of shorts.  With one exception, the ones I do have are always due to wheels of a car or locomotive not being correctly on the track.  The ones that happened with my new Legacy E8s are the exception, and I've sent the set back to the dealer.

I waffled about whether to use PSX-ACs or a power brick, which is one of the reasons I began this thread.  I decided on the PSX-AC because I can still use my KW's throttles to run my postwar trains.  I've tried running them using DCS and the variable outputs of my TIU but I didn't like that so much.

Chuck, thanks for the link.  I went to TrainTek's website, they had the PSX-AC's on sale, and they take PayPal.  I ordered two.

Last edited by RETINPA

Even with a power brick you should still have PSX-AC.   I just don't understand people complaining about the price of a PSX-AC when we all have thousands of dollars invested in these engines.  80 bucks is nothing compared to the price of replacing electronics.



Joel you won't be disappointed.   your arch welding of wheels to tracks is over.

Last edited by superwarp1

Well, you might consider the Postwar #91 adjustable (magnetic) breaker. If you're not running large amperage loads, these things are cheap, reliable and lightning fast. You can get them on the Bay very often for about 10 bucks. I've tested mine against my friend's PH 180 bricks (by wiring the two in series) and the 91s trip first.  I've got a bunch of these things and two of them are connected to the throttles of my ZW.  Instantaneous trips.

Roger

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