Power question

[traindaddy1]

First of all, if this subject was covered in a previous post, forgive me. As you probably know, I am from the HO school and relatively new to O-27. I have been using an older Lionel ZW (115v-60cy-275w) transformer. Three terminals are hooked up to run individual lines. I use the 4th (an inner terminal) to send power to my accessories. Usually set @ 13 volts on the scale. This morning, when I turned on the power to the transformer, the three lines worked as usual but the 4th did not respond. I checked the wires and connections. Seemed fine.

I temporarily hooked the accessories to a separate power source, one of my small HO transformers, and all is OK.

Question: Before I run off to the Lionel Service Center, which is bit of a drive, what should I be prepared to hear? Did I burn out something by having the terminal set at a constant 13 volts? Should I have always used a separate transformer for the accessories? If so, what kind?

Last question, and this hits the hardest: Considering that the transformer dates back to the '50s (refurbished @70s - new power cord), if it has to be replaced, would it be prudent to purchase a brand new ZW or consider a previously owned one if offered by the dealer?

Well, thanks for reading my tale of woe. Any input would certainly be appreciated by this "older" guy.

[Anonymous]

Most likely the roller is burnt and can be replaced inexpensively. This can happen when you drive a lot of wattage for fixed voltage accessories and the contact roller sits in one spot. On my layout I use fixed voltage 12 volt transformers to drive lights and accessories.
As long as the transformer is sound you do not need a new one and it is worth fixing. Make sure the circuit breaker is working properly. I would also insert 10 amp fuses to the individual feeds.

The refurbished transformer is as good as the guy who rebuilds it. Usually a good or bad reputation follows the person.
New ZWs cost over $300 but they are well made. I have not had any problems with mine.

Dale Hz

[traindaddy1]

Dale: Many thanks.

[Anonymous]

In addition to Dale's suggestions, unplug it, remove the top cover [four screws] and determine if the wire from the throttle to the "inner" binding post [C or D?] is loose? I am refurbishing a ZW now that had two throttle wires broken loose from the binding posts ["terminals"]. The wire ends have ring terminal lugs on them which are held on by the flare of the riveted backside of the binding post. A new bolt-on binding post solves the problem.
Parts for a complete ZW rehabilitation including power cord, binding posts, throttle rollers and pins, and horn/whistle rectifier diodes, cost about $20. You can get it done for about $50-55 but the round trip packing/shipping cost on a ZW is awful high. Find someone local if you can't do it yourself.
I no longer replace the ZWs internal breaker but use external four-position cartridge fuse holders or four inline fuseholders[10 amp]. I have also made up four-channel breaker boxes but find that most inexpensive thermal breakers take up to 15 seconds to interrupt.

[Anonymous]

Leonard

4, 10 amp fuses would allow up to a 40 amp flow from the transformer. 40 amps at 18 volts is 720 watts. The transformer is rated at 270. You still need an internal breaker to protect the transformer. The fuses will protect the wires and somewhat the modern engine electronics and rolling stock from a slow acting breaker. For example an aluminum car could derail and its body dragged along the track ruining it. A fast blow fuse would give some degree of protection from this. Shorts can cook PC boards.

Dale Hz

[Anonymous]

Dale Hz
I read Dale M's post regarding amperage flow also. [This same discussion occurred among EEs and "practitioners" on the OGR Forum about 5 years ago].

First ,the net output of the single core, multiple tap pw ZW 275 is 180-90 watts or about 10 amps.

Secondly, you can wire four panel ammeters in-line to the four outputs, fully open all throttles and dead short one, or four binding post outputs at the tracks simeltaneously at max 20 ZW volts, and you will not get an aggregate 40 amp surge or even 20 amps-----without regard to whether you have externally wired fuses or 10 amp Potter-Brumfield Breakers or an internal stock 15 amp breaker.
You will repeatedly blow fuses immediately, and trip breakers within about 5 to 15 seconds. The Lionel 15 amp internal breakers as a rule are not as quick to interrrupt as a good aftermarket thermal breaker wired externally [real fast-acting magnetic breakers cost in the $80-95 range and few if any O-gaugers use them].

Set it up and make the test . It only involves wiring the meters and four pieces of old track, a long screw driver as the villian, the cost of blown fuses and some harmless sparking.

Third, breakers internal or external, and/or fuses protect the transformer from surges caused by derailments,etc,----they are not protecting the engine's solder traces or fragile motor wires. I use QSI PowerGards on each power district to protect from surges and over the past 9-10 years have not experienced any engine board or wiring damage from derailment, including when paralleling 135 watt PowerHouses linked to TPCs for a 15 amp power district..

I understand the theory, the possibility and the argument and i am always open to learn of risks that can harm my equipment. But I have never had it to happen nor heard or it happening in operating practice and along with others who have tried, I have not ben able to create it artificially.

[Anonymous]

Leonard

I understand what you wrote. On my layout I use 10 amp fuses and 36 volt bi drectional zener diodes for the reasons you describe. Fuses blow very fast.

My point is if the transformer has no breaker but instead 4, 10 amp fuses , you could draw 700 watts or more through the fuses without a short and overheat the transformer. since the fuses are in parallel you could draw 40 amps. Please explain what I am missing here.. Doesnt the transformer still need the breaker to protect it? Thanks

Dale Hz

[traindaddy1]

Once again: Thanks guys.