This is an update and reply to all that have read or had input for "Circuit Protection". The engine damaged was a 3V version and both boards, couplers and rear lights were damaged and replaced. Using the Forum input, I started by insuring all transformers were in phase. There are ten Z4000's and there were two ZW's a Z750 and a Lionel 1043 transformer. Testing for phase on a Z4000 to a second Z4000 is pretty straight forward as you just connect the TWO red wires from the back of one transformer to the second transformer and connect one wire to both of the black connectors. With both Z4000's on, moving one throttle to greater than 14 volts, causes the second Z4000 volt meter to show the same voltage as the first Z4000. No red lights or breaker tripped. Repeated the same for the other throttle. Then using Z4000 #2, with Z4000 #1 at zero volts, advanced the throttle and the #1 should then show the voltage as the #2 throttle is advanced. I also tested for voltage between the red throttle ports and all read near Zero. All this is covered in the O Scale Companion, 2nd edition, page 68. All Z4000's were in phase. The two Z4000's being tested, that simultaneously indicate each others volts, was not mentioned in the O Scale Companion. They were, more or less, slaves to one another until the red wires are disconnected for normal train operations. The black wire remains as a phase wire between the two confirmed in phase transformers.
Next the ZW's, which powered some Atlas and Ross switch motors were checked against the Z4000's and they were also in phase with each other and a known good Z4000. Same with the Z750. However the Lionel 1043, was out of phase, as advancing the throttle while connected to a Z4000 would trip the Z4000 circuit breaker. It also p;roduced a buzz before the throttle on the 1043 reached 8 volts. I reversed the polarity on the cord and retested and it tested in phase. Lastly, I tested the Z750 to a Z1000 and they tested in phase to each other, however; the Z750 would not pass the phase test when connected to a known good Z4000? I tried another Z4000 with the same results and also went to my "carpet central" loading track powered by a Z4000 with the same results.
Next, I went to several web sites on testing transformers for phase that used either Lionel or MTH as samples. Lionel has a web site that is a 20 minute "how to" video on testing for transformer phase. It has a lot of good explanations about the out of phase waves, however the O Scale Companion had a better test method. Also, I ran across several web sites that warned not to use a ZW on modern electronics engines as the red light on a ZW is an indicator controlled by a thermal breaker to protect the transformer and not the engines or track. Putting a screw driver across the rails may take the thermal breaker from 5 to 11 seconds to trip as the ZW gets too hot. In the meantime, the transformer can be similar to a "welder". Discovering that, I uninstalled both ZW's and powered their items with the 14V port on the Z4000's. The 1043, which was out of phase, has no circuit breaker of any kind. I uninstalled that item and powered its items with another Z4000 14V port. The distance between the switches and the Z4000 was over 40' and that is why the supplemental ZW's and 1043 were in use.
I set the Z750 aside and added a Z1000 that passed the Z4000 phase test. It's powering some Atlas turnouts that require a voltage higher the 14V. All transformers now have a phase wire connecting each transformer to one another for all ten Z4000's and the Z1000.
I can only conclude that the lead engine of the lash-up, that was damaged during its de-railment, that allowed the wheels to contact the center rail, wasn't protected since the 1043 transformer was out of phase putting combined voltage on the track to about 32 volts during the short, and no circuit protection when using a 1043 for a period just long enough for the Z4000 to trip off, but leaving the 1043 still producing voltage?
The Lionel video on phasing did an excellent job of explaining that any transformer out of phase, regardless if it's powering switch motors, accessories or the track, has dire consequences during a short. The web sites describing the old ZW's that have a thermal breaker, have no place on a layout with modern electronics. You can always install an in line after market breaker on the ZW on the red connection, but why trust that to work fast enough when the consequences of it not working can easily exceed $300, which is almost is the price of a modern brick or transformer? I'm sure an in line circuit breaker would work, but I don't have the knowledge to insure that is the case. I'm talking about
track and engine protection during a short and not transformer protection.
I'm not a graduate of any electrical engineering school, however; I've learned a lot from this incident and from the help of the Forum members. I just read the latest post and it seems the tvs's aren't required either when using Z4000's newer TIU's and MTH, Lionel or other modern electronics engines?
The only other powered transformers on the same circuit now, are three cordless phone 6V transformers that do not have a polarity plug. The same, with three 6V tranformer for the transmission of signal to a closed circuit TV system. I'm not sure how to correctly handle those. There is a second circuit in the building, in the same room, that is on a different leg of the 220V service. Those outlets have the cover plates painted red. I could power all those 6 volt transformers with extension cords to their transformers if required?
Please feel free to amend any actions or conclusions, as I just want to get the layout running again and do so with confidence that another derailment of an engine won't damage the engine. As I look back in retrospect, I've had several freight car derailments, but rarely an engine derailment that actually allows the wheels to touch the center rail.
Thanks.
Moke Mike
