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Hi all,

 

I have a simple layout at the moment.  Two loops connect together via Fastrack switches.  each loop is powered separately with an MTH Z1000.  The Z1000's connect to my TIU (Fixed 1 and Fixed 2) via the barrel connector adaptors MTH sells.  I have removed the jumpers on the curved end of one switch to create isolation between the two loops, and trains run all day long on theri respective loops with no issues...

 

HOWEVER...

 

If I try to cross a train over from one loop to another (eg:  from Loop "A" to Lopp "B") Loop "A" pops the breaker on the Loop "A" transformer.  The train stutters a little, but picks up power on Loop "B" and continues.  

 

I know this might be a phase issue, and I have watched a couple of videos on the subject, but I can't figure out the best way to phase Z1000's with the barrel connectors through the TIU.  

 

Any ideas?   I'd really appreciate any pointers - this is the last step along the route to Xmas layout success 

 

Thanks in advance!!!

 

-Eric

Original Post

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Eric,

 

Do you have the red lug to red terminal and the black lug to black terminal on both inputs on the TIU?

 

If you have a meter, with everything connected, set the meter to AC and measure from the red terminal on Fixed 1 to the red terminal on Fixed 2 on the TIU.  The reading should be close to 0 volts.  If it's like 30 volts or so, the transformers are out of phase.

 

If out of phase, reverse the red and black leads from ONE of the transformers to ONE of the TIU Fixed inputs. Leave the other connections from transformer to TIU alone.

 

Ed

Thanks Ed!

 

You know, I swear I tried this last week (flipping the terminals) and while it took care of the breaker pop, the train would die in the middle.   Tried it again today and took care to run the engine through with a decent amount of speed and... VIOLA!  Backwards and forwards, A to B and B to A.  Seems fine now!

 

Out of curiosity, is there another way to do this without re-wiring the transformer outputs?   

 

Thanks again!!!

Good to hear it worked!

 

Two alternate options:

 

1) cut the plug off one transformer and reconnect the AC cord wires in reverse, or put on a new plug. (not recommended)

 

2) Make a short jumper cord.  Get an extension cord, cut in the middle, splice back together with the cord wires reversed. (not recommended)

 

Both option have you changing the phase on the high voltage side of the transformer.  Reversing the leads as you did, you're changing the phase on the low voltage side.

 

It's more of an issue when you use two Z-1000 controllers with the transformers.  You can still reverse the leads from one of the controllers to the track, but then the horn and bell button functions are reversed on one of the controllers.

 

Ed

 

 

You ARE bridging the two circuits, but as long as the transformers are in phase, the voltage to the loco will be only as high as the highest transformer (which is OK).

 

If they are out of phase, when the two circuits are phased, the voltages add up and could be TWICE the normal voltages (>30V).  That's why phasing is so important.

 

Originally Posted by eddiem:

You ARE bridging the two circuits, but as long as the transformers are in phase, the voltage to the loco will be only as high as the highest transformer (which is OK)...

 

OK with modern power supplies like the CW and Z-1000, but it is a real concern with traditional multi-tap / sliding-secondaries transformers, and even more so if you are using two throttles off of the same transformer, which results in a direct short circuit across the secondary windings with no circuit breaker protection.

I placed a 1 3/8 Fastrack section between the turnouts and removed the jumper wire to isolate each loop.  I then took an extension cord and filed down the "blade" on the polarized plug.  

 

I plugged one Z-1000 brick into the extension cord and plugged it into the wall with the filed down blade to the right.  Haven't had a problem running like this for almost a year.

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