Question on using a PSX-AC on a layout with a TIU wired in passive mode

Please pardon my ignorance, however, what is a PSX?

Barry,

You asked this once before, back on May 16, 2012.  I went back to that post and you were never given an answer, although a link was provided.

Basically, a PSX-AC is an incredibly fast acting electronic circuit breaker with TVS built-in, and an auto or manual reset.  It has other functions, but the CB function is what I'm going to use it for.  I will have it set at 15.4 amps for this installation.

The problem is the PSX has been shown to cause interference with the DCS signal when installed after the TIU, so the recommended location is between the transformer and TIU.  I do not know how the DCS signal works, so that is why I'm asking about using it with DCS in passive mode where the TIU electronics are not between the transformer and track.  Will the signal still be affected with my setup, where the TIU is attached after the PSX?

Ron

Ron,

In regards to placement of anything resembling a circuit breaker, the closer to the source of power (the transformer) the better. The TVS function is already built-into each TIU channel.

The only concern I would have regarding use of these devices at all is that if they do things similar to what the Lionel device that has active circuit protection does (the name of the device escapes me at the moment), it may degrade the DCS signal, as the Lionel device has been reported to do.

Thanks, Barry.

I don't know how a signal in a wire works.  I was hoping that connecting the TIU leads to the power wires between the PSX and the track would mean the signal had a clear path to the engines.  I'm concerned that the signal, when it goes the other way towards the PSX, will be reflected back and cause interference.  I'm not sure if this would happen. 

Another option would be to put the PSX between the PH180 transformer and the TPC400.  I don't think it matters where the PSX is to work, since it will trip faster than either the PH or TPC.

I guess I should just hook it up and see what happens.

Ron

Your picture doesn't show passive wiring to TIU, don't you have a TPC feeding 2 inputs?  G

GGG,

The variable channels are the ones set up with passive wiring.  They will provide the DCS signal for the main lines, which will be powered with more than the 10 amps the TIU can handle.  Power for the main lines with go from two PH180s to the TPC400 to the PSX and then to the mainline terminal blocks.  The output side only of the variable channels will connect to the power wires between the PSX and the terminal block.

I'm using normal TIU wiring for the yard and terminal tracks.  Since I don't need much power to those tracks, I'm using just one PH and TPC to power both fixed channels.

My question is, will the PSX somehow interfere with the DCS signal to the track since it is not between the direct line from the TIU to the track?  Could the DCS signal reflect off the PSX and go back down the wire to the track.  I have no idea, and I guess nobody else does either.

When I get the chance, I'll set it up on my test bench and see what happens.

Ron

I know that the TMCC Direct Lockon kills the DCS signal, so testing that will be a very good idea.

You can, of course, simply put some high-current 22uh chokes in the lines to the mains and that will preclude any issue of it interfering with the DCS.  That's the up side of going passive.

Here's a 34A 22uh Choke that should do the trick.

John,

THANK YOU!  I assume the choke would go between the PSX and where the wires from the TIU connect.  I am going to see if my diagram above works just for grins, but I'm going to add these chokes to ensure no problems in the final installation.

It would probably be a lot easier to just replace all the K-line StreamLighting in my passenger cars with LEDs to reduce my power requirement, but I've already added the additional wire on the pick-up rollers so I think I'll continue as is.  I'll go LEDs as the StreamLighting fails.

Now to order those chokes.

Ron

George,

Your picture doesn't show passive wiring to TIU, don't you have a TPC feeding 2 inputs?

I thought the same thing until I realized that he had the TIU's outputs at the bottom of the TIU. I always think of them at the top in diagrams and schematics.

The chokes go after all the other stuff right before the track connection.  The TIU outputs would be connected, separately directly to the track.  The chokes will simply isolate the PSX and TPU from the DCS signal on the track.

John,

I think I can replace "track" with "terminal block" in your post.  (Unless you are saying the DCS signal wires should be entirely separate with their own terminal block.)

Here is my updated schematic.  The wires from the TIU variable outputs will be attached directly to the 24 port terminal block. 

Hopefully I got it right this time.  Again, thank you.

Ron

Yep, connecting to the terminal block should be fine.  They just have to be in the hot lead of the track power past any circuit protection.  It appears you have them in the correct place. 

Note that you only need one for each track, just in the hot lead.  You don't have to have a choke for the outside rail connection too.

Drawing updated.  Time to start building.

CaPPilot,

   The premise for needing to exceed a 10 Amp Breaker safety on your larger loops is incorrect however, wired correctly in blocks there is no need to exceed the 10 Amps  breaker safety on your layout, we proved this on my 5 level FasTrack layout years ago.  Use the 10 - 12 join method for drops, this means you can have many many 3 foot track sections in just one block, and your 10 Amp breakers will work just fine.  I know because this is how I actually wired my FasTrack layout, however engineering in this manner, some magic lights are required to portray the DCS signal at nearly all 10's.  Engineering wise IMO there is no need for running your layout in passive mode with your TIU.  Remember your 10 Amp breakers are just a safety that safe guards your TIU.  If needed you can use seperate transformer power, as I did, to power your switches & other equipment.

PCRR/Dave

15 Big Silver PRR lighted Passenger Cars pulled by a P2 GG1 over several different blocks, safe guarded by the Scott 10 Amp breakers in front of the TIU. - Worked great.

Dave,

He can, indeed, legitimately draw more than 10 amps. He has paired 180 watt bricks joined by a TPC for two TIU channels, and is wired for those channels in passive mode.

Barry, I think Dave's point is there's no need to supply the track with 20 amps of power, just arrange more power districts so that you can run multiple trains on one loop.

John,

That may have been Dave's intent, however, that's not even close to what he stated. Although he may have meant to discuss power districts, he didn't.

OK, I'll allow that it wasn't crystal clear, but I'm pretty sure he's talking about power districts.

FWIW, I've tried paralleled PH180's when we had issues with power on our modular club layout.  I didn't like it, and I don't intend to go back.  20A seems to be able to do a LOT more welding than 10A when you have a derailment.  Usually, only one PH180 breaker would trip and leave power cooking away.

Barry,

   Guns is correct about my intentions, again my wording was poor because of not using the district ident.  Sometimes my wording is poor on the DCS engineering.  My point was there is no need when set up properly, to use the TIU in passive mode.

Barry I can under stand where your were coming form also.

PCRR/Dave

John,

I went back and forth on whether to use the TIU and two PHs as in the schematic above, or go the power district approach which has been discussed on the forum before.  My concern with the power districts is I need more than 10 amps for just one train (three powered engines with all sound and 10 plus passenger cars with non-LED lighting).  The introduction of the incredibly fast PSX helped me decide to go with my current approach.  The PSX will be set at 15.4 amps, which should meet my requirements.  On my old layout, my 8+ car passenger trains pushed the 10 amp limit of the PH, so 15 amps will work.  Plus, I will not need the circuit protection in the PH or TPC because of the capabilities of the PSX.  I will not have the only one PH breaker working issue you had.

Ron

If you have a derailment that results in the current sitting around 13-14 amps won't you have some serious engine damage?  Since nothing will trip?  G

G,

  In reality this was what 1st crossed my mind when I posted and advised him that running as he was doing was not necessary, if the layout was constructed in a different manner, and 10 Amp breakers were used.

PCRR/Dave

GGG, that's exactly what seemed to be happening to us on the modular layout.  I suspect the PSX would be better than just the parallel bricks, but I won't be running with more than 10 amps on the rails at any more modular shows!