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Put a screw driver or large gauge wire between the A ,B,C,or D post and the U terminal and turn up the throttle. It should trip after a period of time. If the breaker is bad replace it with a suitable replacement. This is necessary to protect the transformer and will protect heavy bus wire but not thinner branch wires. For running modern engines add appropriate external protection,described here. 

 

http://www.jcstudiosinc.com/BlogShowThread?id=486&categoryId=

 

Dale H

The 5F circuit breaker test for the ZW transformer places a .1 ohm (one tenth) resistor across the output terminals of the transformer.

With this load, the 5F manual says the current should be 30 amps (thirty), and the circuit breaker should take between 11 and 40 seconds to trip.

 

IMHO that is a lot of current, and an awfully long time, which is one of the reasons I aways use postwar Lionel #91 adjustable electromagnetic breakers on all the power posts that are in use.

The internal breaker is there to protect the transformer. It probably would not protect your wiring or anything else very well.

 

The resistance load in a Lionel test bench is a heavy piece of nichrome ribbon.  They get HOT!

 

I absolutely would not use a postwar Lionel ZW transformer that did not have a properly working circuit breaker.

I would test the breaker as suggested above. If it doesn't trip replace it with one from a parts dealer like Jeff Kane at www.ttender.com

Part number ZW-232 for the type mounted to the aluminum bracket or Z-22 for the square black type mounted to the bottom of the case.

 

ZW's are encased in Bakelite which doesn't melt so yes you can fry the wires and coil inside but good luck getting the bakelite case to burn, melt etc. I've tried a propane torch on Bakelite.

Originally Posted by gunrunnerjohn:

Note that while the ZW transformer circuit breaker protects the individual outputs, there is one large hole in it's protection!  If you short two outputs together and they're set at different voltage settings, there is no path through the circuit breaker for that case, and it'll just suck down juice until something melts!

The ZW has NO protection for the individual outputs.  Only the common bus has the circuit breaker, hence the problem you describe above.




quote:




Note that while the ZW transformer circuit breaker protects the individual outputs, there is one large hole in it's protection!  If you short two outputs together and they're set at different voltage settings, there is no path through the circuit breaker for that case, and it'll just suck down juice until something melts!





 

This is the second reason for using external breakers on each of the "Hot" terminals in use. The ZW transformer can be damaged by a short as described by John. I have seen it.

 

Unlike working on the trains, there are safety issues associated with working on transformers. There is house line voltage involved, and the transformer has exposed line voltage connections. Folks should consider this before working on transformers.

Fast acting fuses or breakers rated near 8 amps should work very well for each lettered(A, B, C, D) output on the older 250 & 275 watt ZW's.

The way Lionel has the older ZW set-up is that only the return or common wire has circuit protection. As one or two others have mentioned before, you can almost weld with the older ZW's before the internal breaker trips.

 

J Daddy,

Thermal breakers are for use with stuff like air conditioning in a car. Personally I stay away from D.C. circuit protection in an A.C. envirement.

Lionel transformers put out A.C. voltage, your auto has D.C. voltage, so using auto circuit breakers is not the best thing to do.

For the average person to understand about electric work like A.C. and D.C. volts, D.C. is straight power like a battery, A.C. fluctuates between positive and negative many times a second-thus the name alternating current.

 

Lee F.

The postwar Lionel #91 breakers aren't too difficult to find, but one does have to keep an eye out for them.

One word of warning: If the adjusting knob on the #91 is turned down too tightly, the breaker will never trip. Sometimes you find them with melted cases. I'd steer clear of those because they were probably abused (by screwing the knob down too far.

I have been using the same ones for over thirty years, and have never had one fail.

 

I adjust mine by putting the biggest load I am going to run on the tracks, and loosening the knob until the breaker trips. Then I turn the knob back down 1/2 - 1 turn, and it's all set.

Get some resettable circuit breakers for 6, 8 or 10 amp like the one shown below.  Littlefuse makes them.  Use one for each transformer output. 

 

I installed them on my control panel and wire a 12 to 18 volt bulb (behind a red lens) across the circuit breaker contacts so the bulb comes on when tripped.

 

 

The circuit breaker reset button and red indicator light are shown in the upper left hand corner of the control board below.

 

 

IMG_3149

 

Works for me.  It is the same circuit that is used on a Marx circuit breaker device that is wired in between the transformer and the wire to the center rail of the track.

 

Charlie

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OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)
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