Lionel Type ZW transformer

[San Jose]

Hello out there:

I have a (nominal) 275-watt ZW transformer that I bought used.  I find that I cannot run two trains on electrically separate track loops at the same time using any two combinations of posts (A/D, B/C etc.) to run the trains.  The symptom: the trains stop and start, and stop and start.  Without some guidance on what kinds of measurements to make, I'm wondering if any of you have experienced this kind of problem and if so, were you able to fix the problem 

It seems to me that there might be some kind of voltage leakage across circuits but I'm no whiz when it comes to this kind of electrical stuff.

I'd appreciate any help you can give me.

Thanks,

Nino from San Jose

[servoguy]

You should be using terminals A&U or D&U with U connected to the outer rail.  If the trains keep stopping, you either have a bad circuit breaker or you have a short somewhere.

[Rob412]

Can a train run on each loop individually?  If so your track is ok. An electric meter that measures volts,amps,and ohms is an invaluable tool in this hobby. Check the amp draw on your ZW this would tell you if you have a weak breaker or possibly an engine or car could be drawing to many amps. I once had a doubleheaded passenger train with about ten pass. cars and the ZW couldn't handle it. The train acted exactly the same way.  You could also check (if you have tubular track) the insulators on the middle rail. A missing or off center insulator can do the same thing,  even new track I have got was missing an insulator now and then. 

Good luck

[phillyreading]

Have you tried using terminal A to the center rail and a U terminal to the outside rails? Terminals A B C & D never get put together or you may encounter extremely higher voltages then what is normal. On terminals A & D the whistle lever will work with these. With the older ZW transformer you can almost weld with it as the internal circuit breaker is connected to the common side and not the A to D terminals.

[ADCX Rob]

phillyreading

Have you tried using terminal A to the center rail and a U terminal to the outside rails? Terminals A B C & D never get put together or you may encounter extremely higher voltages then what is normal...

Voltages, no, but combining these posts can results in very high current overloads that are not circuit breakers protected.

[lionelsoni]

Rob, in terms of steady-state voltages, you are quite right that the voltage differences among A, B, C, and D are no greater than between any one of them and U.  And you know that I agree with you about the high fault currents.

But the fact that phillyreading described the voltages as "extremely higher...[than] what is normal" suggests to me that he meant to refer to the inductive voltage spikes that may occur when those outputs are connected together intermittently, which can be hundreds of volts. 

[phillyreading]

Like Bob n. mentions I did have an engine run away one time when crossing a block with two different outputs from the same ZW. Also the common side has the circuit breaker and it would be best to add 8 amp circuit breakers to the output terminals A B C & D.

[San Jose]

Apologies for my note on the ZW transformer issue!!!

I was not clear about running two trains from a ZW and the starting/stopping problem.  When I said A/D etc, I meant that I was using A-U and D-U post combinations to run the trains.

I hope that doesn't discourage you from coming up with thoughts about the problem I described in my first note.

Nino from San Jose

[cwburfle]

You might have some "U" terminals that are not working. The "U" terminals are connected to each other, by metal bar running between the four posts. It is common for one or more of the terminals to break away from the bar. Sometimes the break is not visible.
If you have  meter, check for voltage between a power post, such as the "A" post, and each of the four "U" terminals.
If you do not have a meter, you can use something like an illuminated accessory or a 12-18 volt light bulb.

[ADCX Rob]

San Jose

I find that I cannot run two trains on electrically separate track loops at the same time using any two combinations of posts (A/D, B/C etc.) to run the trains.  The symptom: the trains stop and start, and stop and start.

My guess at this point is that 1)your circuit breaker is worn out and 2)your short circuit indicator bulb is blown out.

[phillyreading]

If you know something about wiring, check the electrical wires inside your transformer as one may have fallen off. I had a wire fall off my post war ZW before I bought it so I got it for $30.00 sometime in the 1960's in Stratford Connecticut. What I did was to make a small hole in the housing to put the wire through without pinching it and then mount the wire around one of the terminals, I think it was the A terminal wire that came off. All the common terminals are connected by a copper terminal strip inside so you can use any common with any A through D terminal and not worry any. I have also seen the copper strip come off one or two terminals as I was looking to buy a second post war ZW at a train show.