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Some time ago, my KW began to smoke and get hot.  I pulled the plug and set the thing outside to air out, but I never did anything about it.

Today, I partially disassembled it and found several problems.  First, one of the rollers had come out of its holder (the roller is intact, but the pin seems to have disintegrated:

Rollers-Core

As you can also see, the core look pretty rough.

On the other side, the ends of the cord have become detached from their connections (admittedly, one broke lose after I pulled the unit apart):

Cord Ends

The wire that powers the light bulb indicating a short was lying loose in the case when I took the top off; it appears to have been repaired/extended at some point in the past:

Light Wire

You can also see here some roughness in the laminations.

 

I come to the assembled wisdom of the forum for advice.

Is this thing economically repairable?  Or should I peddle it (on the For Sale board here) for parts to someone who works on them regularly?  The case is in great shape, as are most of the handles.  It looks like the interior has salvageable parts, too.

If it is repairable, is it something a novice can/should do?  Understand:  I can solder, trace diagrams, and follow directions.  But I have never worked on a transformer before.  Everybody has to start somewhere, but is this project a little too much as a first project?

 

Any and all comments welcome.

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Everything looks economically repairable except for the core. It is very possible that it looks worse than it is and find that it is still functional. So far, the only mandatory replacement parts are the rollers and pin. They are inexpensive (probably cost more to ship a set then the parts themselves). Here are internal wiring diagrams:

 

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I am interested in what answers are given ,because i also have a kw that i got for nothing that i would like to repair myself if possible & i can solder also ,but i am not sure if i understand what should be done so i will be watching the responses you get ,if you do decide to try it yourself if you can post pictures it would help me a lot ,whatever you decide i wish you luck.

I’d tend to agree with BMORAN4 yet again today, this could just look worse than it is....possibly someone over the years before you altered the circuit breaker, by evidence of the overload bulb wiring...I’d look at the breaker to see if there’s evidence of tampering......the low voltage winding looks like the work of an overload not tripping properly.....you may be surprised on how well it will clean up...in addition, the globs of glue on the back side of the terminal posts give an indication that some or all are loose, and in need of proper repair....loose terminals could surely cause a load issue....in the form of heat!.....doesn’t look at this point that all is lost, but it certainly take a few parts and some sweat equity........Pat

Looking at each end of the core/stack the windings look like they are OK with shellac on them. The bit that is pinkish indicates to me where the main heat source was and that all the shellac is missing. Either side is black from charring which also indicates that the integrity of the shellac insulation is doubtful. 

I would suspect several of the windings are now shorted. Any attempt to run it up again is more likely to result in further overheating and is it really wise from a safety aspect to do this?

These things happen and sadly it looks like the transformer is not viably worth saving.

I would check the ac winding that looks like it been very hot and check continuity to the metal case ground, and the other  lead from the VOM volt ohm meter on continuity you should not read any shorts or resistance from ground to either side the   ac plug that feeds that  winding IF YOU READ ANY RESISTANCE THE TRANSFORMER WINDING IS SHORTED TO THE CASE AND IS TOAST OR SHOT. if you do not read any resistance to the case and threw the winding you probably can clean  up the winding with a  pencil eraser and go from there, there is always a possibility you can clean it up Providing  the winding is not shorted to metal case ground winding of the transformer!

 

I bought one which the core looked just as this one does at a garage sale for $5 back in  the mid eighties and It is now functioning but only after a crazy amount of work. No repair shop could afford the time to tackle this. However as a labor of love it can be done.  The first test is to read the resistance of the primary winding and it should read about 6 ohms. If the power cord is intact you can read it through the plug I would add another .1-.5 ohms if reading on the end of the power cord. If you read 6-6.4 ohms Good.  Now connect one of your meter leads to the laminations and make a reading through both prongs of the plug to the core laminations. A reading through the cord to the laminations should be an open circuit !   If both of your reading are good then it is possible to repair the secondary winding but it is some work. You need to find a motor rewinding service in your area and get some winding varnish from them. If your primary tested bad you "could" take to the motor shop and they can wind an identical coil though I don't know what that would set you back today, I would not bother. You will have to get the windings and laminations out of the case and frame then seperate the laminations and remove the two coils. Once you have done that you will spread the windings of the secondary about 1/3" per turn and take a soft wire brush and knock off any scorched varnish. Once you have done this you will have the coil spread a couple of feet and this is how you will brush on at least two coats of varnish leaving no bare spots. I stretched my coil down the work bench and put a piece of duct tape over the area where the wipers ride to keep the varnish off right on the top edge. However the sides where the winding press against one another you need a good layer of varnish. Once the varnish is dry you will compress it till it is just long enough to get in your wifes oven and hang it from one of the wire racks by the two ends of the coil. I do not remember the particulars, temp and time, of the bake but I am sure any electric motor shop you get your varnish from can tell you.  In fact I bet you could get them to do the varnish and bake part of the project for not too much $. Once varnished and pressed back to the original length you can hold it together with some loops of tied cord  till back on the core. It all goes back together in reverse order. Double check the schematics posted here for your wiring connections.   OR YOU COULD PULL OFF THE HANDLES, CASE, WIPERS, LAMP LENSES............ ETC. AND SELL THE PIECES ON EBAY.       j

hokie71 posted:

Kudos to john for a scholarly and detailed summary. As I read it, I wondered what the conclusion was heading to. I laughed out loud when I read the or....... Part. For a $50 purchase to replace this, not much doubt on the conclusion. As much as I like interesting projects, the benefit - effort ratio is not promising .

When I did the one I speak of, I was freshly divorced, and a nice KW was over $100 plus shipping. I had house payments, lawyer bills and child support payments. Alone at night for the first time in over ten years what else ya gonna do but varnish transformer windings.   j

I'll chime in here with the answer I give people at train shows. My Dad was an electrician for 40 years. If you aren't sure and/or don't know what you are doing,

leave the transformer fixes to a pro and/or electrician. IT IS NOT worth getting electrocuted and/or burning your house down for a DIY project on an electrical transform that has 110 volts going into it.

Google "Lionel KW" and you'll see them listed for under $100. Any professional repair will undoubtedly cost more than that. Unless you're an electrician and/or really, really know what you're doing don't attempt it yourself. If you do, have the number to your local fire dept. on autodial.

Thanks for all the replies, guys!

Fro the record, though I am no a professional, electrician, I have done quite a bit of electrical work, including 110 volt, so that part doesn't scare me.  But the amount of work (when I am anything but blessed with much spare time) makes the project not just impractical but impossible.  I especially appreciate John's thorough write up.

All that said, look to see the unit--or at least parts of it--on the For Sale board as soon as I can find out what the shipping costs will be.  I hope one of the guys out there who do work on these might find parts of it useful enough to pop for the shipping.

 I repair and rebuild both KW and ZW transformers. From the looks of your pictures it appears your transformer has seen some very high currents for an extended period of time. It looks as though one of the cord leads was burned off.  It is difficult to look at the pictures and determine exactly what happened but I am guessing your circuit breaker was not working properly and a short circuit current occurred And the circuit breaker did not open.

 I think that to try to repair it would be a bad decision economically. I can sell you a KW transformer with  a beautiful case, that has been totally rebuilt  with new rollers, a new circuit breaker, a new cord and the rectifier disc converted to a diode. The cost would be $85 plus actual shipping cost.

I could sell you a ZW transformer with all the work done that I’ve listed above on the KW for $165.

I have sold many rebuilt  1033, KW and ZW transformers on the forum and at TCA train meets over the years and I’ve yet to have a callback.

If you decide to tackle your KW, I will be happy to help you in any way I can. Just let me know.

Jim Lawson

 

 

gunrunnerjohn posted:

Jim, I think he's found a good core, so it might be an educational experience to rip it apart and install a new core.

Yes the 'smoke' in the old transformers is not nearly as expensive as the 'smoke' in electronic components.. Easy to 'let' out, but extremely hard to put back in... Of course I'm not speaking from personal experience... lol

O Gauge Jim posted:

...From the looks of your pictures it appears your transformer has seen some very high currents for an extended period of time... I am guessing your circuit breaker was not working properly and a short circuit current occurred And the circuit breaker did not open.

My guess based on the pics is that "A" was set to about 7 volts and "B" was set to 13-14 volts and then something connected/shorted the two together.  There is no circuit breaker in the KW to prevent this.

Thanks for all the replies! I think going forward, my buddy is going to try and repair his unit utilizing parts from an old damaged KW I had received. The core from my unit looks pretty good, I'm sure my cousin wouldn't have bought it non working. That said, in 40ish years the cord is bad and that's why opened it to begin with. Assuming we have all the parts we need, well post back to the forum the rebuild. Based on what he runs, I don't know if we should worry about the breaker, at least swap from my unit. But adding a 10 amp resetting breaker in the line outside the unit couldn't hurt. 

As for O Gauge Jim, Thanks, you may be needed! 

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