Z4000 trouble all of a sudden

You should not be reading any current when you raise the handles with nothing on the track.  It sounds like you do somehow have a short somewhere.

-Dave

With all trains off the track on the problem track, turn up the throttle part way. If you get any AMP reading, then there is a short someplace. With the throttle still on partway, run your hand along the tracks, feeling all 3 rails. A short in the tracks will result in a HOT spot.

Check also any feeders that supply power to various parts of the layout from a common point, if you have any. Could be a wire may be touching, since you stated you recently rewired the layout.

Larry

paul 2,

The Z4K is a wonderful transformer. The hardest thing to do is listen to it when it is trying to tell you what is wrong.

Rich Melvin made a fantastic DVD that covers just about everything the Z4K can do. 

I started this morning looking for the problem. So far I found that one handle on each Z4000 causes the red overload light to come on along with a hum that gets louder as I raise the voltage. I am going to start to trace wires. I am glad I decided to go with different colors for each mainline. It will make it easier to trace ( I hope ) I also have used one common ground for all the mainlines. It just seems strange that after a bit of time of running the layout this shows up. You would think it would of showed up immediately if I crossed wired something. As always all help greatly appreciated...............Paul 

Disconnect the wire to the Z outputs.  Start and than raise voltage.  If no short the transformer is most likely ok.  Put a meter to the wires that caused the short with no engines on the track.  Does it read 0 ohms.  If so a track or wire issue is your problem.  G

Sounds like some more details may be in order.  You mention 2 upper mainlines, one running Williams, one Legacy, but then you mention the 2nd Z-4000.  What is it hooked up to?

It may be beneficial if you can do a brief wiring sketch and take a photo of it and post it. (or draw it up on the computer - whichever you are more comfortable with)

A good initial cut at details would include making sure you say which rails red and black are connected to for each transformer/loop and also whether any of the loops are interconnected with turnouts.  An actual detailed schematic of the track layout is not likely needed.

-Dave

Dave I just got done taking the wires off the handles that were causing the overload. With the wires off I can turn the handles all the way without an overload light. Also when I do that all that increases is the volts to track display. The amp displays stay at 0. I have two upper mainlines and two lower mainlines. The grade between upper and lower mainlines is powered by the inner upper mainline. I rewired the tracks a number of months ago. So each mainline has its own color, I have done a quick check to see if I tied the wrong wires together but so far I do not see anything out of the ordinary. With the two Z4000's I have a TIU for each. The way I wired them was to come off the post down to the TIU's from the back side of each I ran the wires to two bus bars. The power bus bar was sectioned off to four and the ground bus bar was made all one ground. So up until a day or so ago I was running four trains on four mains. What it is possibly looking like is something has changed on the inner upper mainline and the inner lower mainline but for the life of me so far I have not found the problem. I am attaching how I connected the wires on the control panel............Paul

If you are using tubular track, a piece of insulation might have deteriorated or slipped - perhaps just a little, such that it shorts only when the engine puts weight on it.  In addition to trying the transformer when it is disconnected from the track, you can also try hooking it up to a test track and see if the problem is duplicated.

I forgot to mention in my last post I am using gar graves with Ross switches....Paul

Reconnect the TIU to the Z output, and disconnect the track from the TIU output.  Try again.

If it shorts the TIU TVS is shorted.  Repairable.   G

GGG I took both common and power wires off each handle. What I learned so far the ground is okay but something has crossed with the power. With ground on no red light when turning the handles however when doing the two power wires the red lights comes on. The two power wires in question each go to separate TIU"s.....paul

Hi-- Just a note.  I personally would not use any expensive equipment, meaning TUI (or an expensive transformer as current source) in the path leading to a short circuit out on the layout, in searching for the location of this short.  Instead, invest in a small multimeter, and use the ohmmeter feature to search for low or no resistance to the common return.

For example, the breakers on the Z4000 may be UL labeled, but that label only requires that they operate once.  It is generally considered that breakers and fuses should not carry more than 80 or so percent of their rating at the expected load, as the calibration of the breaker or fuse will be changed. (In American practice a 15-amp breaker does not open at all below 17-amps-- or 113%-- to account for this, and continuous loads (any load on for four hours or more) must not exceed 12 amps (1440 watts on a 120-volt lighting circuit).  Even at 20-volts these restrictions should be observed, because these effects are due to heating by the amount of current.

In using a multimeter, you should be careful not to subject electronic circuits to the relatively large test currents from the battery of this device as ohmmeter.  Also, you should not subject such circuits to the relatively low battery voltage of such meters if it would act in place of their regular power supply (again, as ohmmeter).  The voltmeter feature may overload such circuits.  There are various electronic meters (more pricey) that can be used if this is a problem (that is, be careful with the TIU's).

Note that many toy train power supplies will not provide a voltage less than 5 or 6 volts.  Note that testing for breaker operation by shorting the track is not good for the breakers.  Service stations test at 200% of rating, and not very often.

Just my opinion.  We have all, including myself, ignored this advice. 

--Frank

I am just getting you to isolate the equipment that works.  If both handles are shorting, you definitely have something crossed some where?  If output of TIU disconnected and the short is gone, than TIUs are ok.  What maintenance on the track were you doing last?  G

Paul, first I would isolate the Z4k from the TIUs. Test for short. If ok, connect Z4k to TIU input. Keep TIU output disconnected (I know, it's a PIA). Power up TIU, then power up track. If no short, TIU should be ok. If shorted, the TIU is in need of repair. If OK, connect one TIU output to track, try for short again. If no short, connect other TIU output, and try for short again. If shorted, disconnect first TIU output connection and try for short. If ok, now you know which track is having problems. My money is on a piece of metal debris on the track, causing a short, unless you smelled frying electronics right before the red light. The other option is to break the track into several sections, which will be tough since you seem to have all of the track screwed to the benchwork. Test for continuity with the TIU out put disconnected, so no voltage goes into the TIU or Z4k when testing. The track might have an insulator missing, as noted previously. Keep us posted. 

One handle on each Z-4000  shorts.  What does each handle power?  Which tiu channels? I might look there first, removing center rail track feeders one at a time until the short clears up. Or disconnect them all and add then back one at a time.

Would a reversed track feeder slowly bring out the short?  Anyway you'll find the problem. good luck

Thank you for all the suggestions and help. This morning I start looking for that needle in a haystack..................Paul

To all of you a heartfelt thanks for all the suggestions. I am up and running again. It was not a short per say it was too many engines on a track. I retraced what I had done different. After a day or two of a senior moment I narrowed it down. At the bottom of my grade I had a manual Ross switch. I had some switches left over when I redid the yard with a four way. I did not realize the new switches are track powered all the way through now so when I put in the new switch voltage was going into two mainlines. The overload light was then going on because I had engines sitting on yard tracks. Once I took my Dremel and separated the yard tracks everything went back to normal. Sometimes the simplest things are right in front but we always think the worst...................Paul

 I like it when nothing is broken and fixed. good stuff.

Look for a loose wire on the TIUs or terminals that may have rotated and is touching an adjacent one.  Look on the track to see if possibly something like a bit of a wire strand or screw from a loco may be shorting out the center rail. 

How many locos do you consider as having been too many?  I have had 8 or so sitting stopped on one Z4000 handle with no problem.

Paul--  Not to be overlooked is a connection across the third rail insulating pin between power districts served by two different handles on the *same* Z4000.  I assume here those are used for trains, and the two smaller knobs are used for accessories, like the PW ZW.  Still, what I am getting at may apply to any two of the four outputs.

What happens, at least in the PW ZW, is that any slight voltage difference (even as little as 1 turn, or one-third of a volt) will create a shorted turn within the transformer output coil on which the carbon rollers bear.  This "shorted turn" is actually being completed out on the layout by the connection between the third rail zones-- that are normally isolated by a plastic pin.  This actually causes the full short-circuit current output of the PW ZW (about 40 or 45 amps) to flow in this single shorted turn-- it does not pass through the transformer 15-amp breaker in the ground return (PW ZW).

The PW ZW cannot detect these currents.  Of course they occur whenever a pair of rollers pass over the plastic pin.  The wires in the output winding are quite heavy (#14 square or effectively ~#13) and do not heat up instantaneously by any means.

[There are about 42 turns in the variable coil covering the marked range of 14 volts, from 6 to 20 volts-- at 115-volts input then, now operated at 120-volts.]

The design of the Z4000 is based on the PW ZW (MTH quote).  I believe this is true in more ways than just the nominal output voltages and the arrangement of the handles.  The PW ZW uses a whole set of secondary coils with physical switches to deliver the various functions, and moving coil contacts to deliver the varying voltages.  The Z4000 delivers all this with electronics and solid state switches.

Whether or not the Z4000 can overheat in the same way, when the plastic pin between the output of the two handles is bridged, is not entirely clear.  But what is clear is that by its era, the UL label requirement had been changed to state that any such interconnection be cleared automatically within 60 seconds.  And the patent for it states that this is done (I assume in the same 24 seconds mentioned following).  A similar 60-second limit is placed on clearing any excess of 180 volt-amperes to common from any of the four outputs, and the patent states that this is done at 24 seconds in excess of 180.  It is either not clear how dead shorts (more or less) are handled, or how quickly; obviously the UL breakers on the outputs will handle these in *any case.   (*This does not include the case where 100 feet of #16 wire goes out to the TIU, and 100 feet returns-- from my experience after joining a club layout.  So, more but not less...    )

I find it very curious you could determine that the short was not in the common return.  Did you also see that the short indicator did not appear immediately?  Presumably you could do this by disconnecting the common return(s) from the common terminal post(s) on the Z4000.  (BTW, I am not sure this circulating current can pass between *two* Z4000's-- at least not in exactly the same way, because in this case, the circulating current in the earlier PW ZW's would have had to pass through the 15-amp common breakers in these earlier transformers.)

This situation suggests that the Z4000 may be detecting interconnected hot side outputs.  Try to observe carefully if this is the case, and report your findings here.

Since the Z4000 has four UL breakers on the back (2@15 amps? and 2@10 amps? I cannot recall, could you report?), I infer that these are on the hot side of the output.  However, I don't know if these are on the hot side (of the low voltage hot, I'm not referring to anything on the 120-volt side) of the output, but it would seem so (the patent may say, but I cannot recall beyond their being separate and downstream of the electronics).  In that case, any circulating short-circuit current would have to pass through two of these breakers (there are 6 combinations).  If you had an electrician friend with a clamp-on ammeter, you could measure the amperes in this circulating-- or other-- short, which might explain the delay in these breakers opening.  For example, a 30-amp current might take 2 minutes to open a 15-amp UL breaker.

I'll read back through all your reports, with this possibility in mind.  Also, look on the layout for a car with two rollers bridging an isolating pin.  (Pin or gap, either.)

Added paragraphs:  If the electronics in the Z4000 interrupt the short (red light comes on) then the UL breakers might not open.  You might want to time (in seconds) how long it takes this red light to come on, as best you can, and report.

Oops, I see I am breaking my own advice about using the Z4000 as a test instrument.  See it you can borrow a Z4000 from a friend...     Or just report any delay from memory.

--Frank      (Edit added last 2 paragraphs.)

Paul--  In your first post you wrote:

Both Z's are plugged into a terminal strip which is hooked up to a 20 amp line  for the Z's.

In your second post you put up 3 overlapping pictures of wiring.  For example, in the upper photo, the power strip is sectioned into four, each section for one of the four main lines.  Three green wires attach to each other at the uppermost section.  Here the lowest of the green wires goes off to the left and appears to down to the leftmost set of black/red inputs shown as wired on the leftmost of the four pairs of inputs at the rear of the TIU's in the lowest photo, specifically a red input (although hard to see).  Is this (one of four such, in its own color) of "...a 20 amp line  for the Z's." ?

The other two green wires in the upper photos appear to go upward (to the two Z's?).  To which Z does each of these two wires go, and to which post or handle on which particular Z?  What is your normal voltage setting on these particular posts or handles?

Is it that each of these two upper green wires supplies 10 amps?  Are you wired to supply 20 amps to the green mainline TUI channel?

It appears that your problem was in some way related to the interconnection of two of the mainlines power supplies that occurred through the third rail of the manual switches, rather than the numbers of engines sitting on track in your yard.  In this, I agree with RJR that there is a little more to this than the engines.

--Frank

Frank I can see where even when I proof read my responses I miss something. I meant to say I had a 20 amp line brought to the attic for the transformers. I bought a 10 plug surge suppressor and I have the Z4000's plugged into that. The colored wires on the terminal blocks which are 20 amp terminal blocks are for each mainline. So one power wire in and then two out to the track. When I put in the new Ross switch it combined two mainlines. Once I put a gap in the middle rail with the Dremel to separate the yard tracks my problem went away...........Paul