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I got a 1948 VW transformer yesterday that I'm going to refurbish.  I'm planning on updating the rectifiers, replace the rollers, and replace the power cord.  The power cord on my VW is awful.  It is so badly dry rotted, that when you bend it, you can see the live wire through the crack. 

Now I have a ton of computer power cords, and what I was going to do was chop off the end of a computer power cable and use that.  They are grounded though with 3 wires and I wonder is there a safe location to ground the middle wire to inside the VW/ZW?  

In the interest of safety, I really like the idea of grounding the VW in a safe location so if something happens, it will trip my house circuit breaker. 

 

 

Original Post

The UL Standard for toy transformers does not allow for grounded line cords.  All exposed metal parts on a transformer are supposed to be "dead metal parts".  This is tested by a dielectric strength test.  Should the base be grounded and an internal failure allows line voltage to leak at the terminals you can have a lethal voltage differential.  Hence the dielectric strength test.

When I did the RoW transformer I followed the UL Standard for sporting goods transformers which allows for a 3 wire plug and outputs greater than 190W.  It also passed the dielectric strength test.  

Just for fun one night we hooked up a ZW to the strength tester and it failed.  Tying the inputs together and the outputs together, you apply 1000V + 2 x the highest rated [input] voltage for 1 minute to the grouped inputs and the grouped outputs.  The ZW broke down (failed) at 600V.  It should have held at 1240V.

Once again, more than you need to know.

Lou N

 

Thanks everyone for your help.  I have went and used a high amp 2 conductor power cable for my VW.  

However I still need to order parts.  Where is the best or easiest way to order parts.  I have two cosmetic parts I need to replace.  The silver ring on the port side is missing in the unit I have below is the most important part and I also want to replace or cover the badly worn L logo medallion on the top of my unit. 

So I want to order that ring, the diodes, and anything else useful for upgrades in the unit.   I actually have one of those dual 180 watt brick and modern ZW units new in box but I really don't want to dig out all that stuff just to setup a living room loop.  This VW would be perfect for my living room setup bu t I do want it upgraded so I can use it with modern stuff.   

On top of that i just LOVE that the VW I have is from 1948.  I was born in 1967 so this unit was just about 20 years old when I was born.  its 72 years old now.   I also got a really nice Santa Fe 2343/2343c/2344 F3 ABA set that actually is in surprisingly good shape, well used but still bright and fun looking.   According to a website, its the set from 1950-51.  The rollers on the powered unit do need replacing though.  

 

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@Dave45681 posted:

A VW looks like a ZW, but has lower power capability.

Same for a V vs. a Z.

-Dave

Exactly.  When I opened it up, i compared the size of the coil assembly to a ZW, the ZW is bigger than my VW.  I imagine it would be easy enough to swap out the coil assemblies but I highly doubt that there are many ZW coil assemblies just laying around ready to sell to Bo.  LOL 

I'm going to refurbish this baby up and get it somewhat modernized and just enjoy it for what it is and the history it went through.  I mean it was born a scan three years after WW2 and before the Korean War.   

I just imagine that this was something my step-dad would have dreamed of getting when he was a youngster pouring through the Lionel catalog.   

 

@ADCX Rob posted:

It's actually rather difficult... the brackets, dials & contact arms are all unique to the VW.

I'm not going to do it.  If my VW works fine as is after doing the basic upgrades and maintenance parts (quick blow circuit breaker, whistle diodes, graphite rollers) then i will just keep it as is.  No need upgrading it since it will probably have plenty of power for my needs. 

Notwithstanding suggestions above, when rewiring a transformer, I always use polarized plugs, BUT, I do my transformer phasing before closing up the transformer, so that thereafter whenever plugged in, it is in phase with every other transformer.  After connecting the line cord, if out of phase, I unsolder, switch wires, and resolder

In my opinion, to operate this antique electric trains safely a few things should be done. All transformers should plugged into a power strip.  The power strip should be turned off when any of the transformers are unplugged and any time the supervising adult is out of the room. The power strip should plugged into a GFI outlet. There should be external circuit breakers on each of the variable voltage outputs, maybe 6 to 10 amps, and a single circuit breaker on the common output, maybe 15 amps. 

@Susan Deats posted:

Re: Parts

Consider this upgrade for Whistle Diode repair.   Replacing ZW Whistle Rectifier Discs with Diodes

One minor caveat with this method:  If you are operating modern electronic whistles, you will need to reverse the leads to the tracks, as this technique changes the half-wave DC from upper to lower wave and will operate the bell circuit instead.   

Mitch 

 

I don't know which thread I read tonight is more fascinating/frustrating:  this one or the one about the couplers. I'm told by my friends who spend a lot of time on computers and blogs and forums that the answers and remarks on this site are pretty typical of the web world in general. But for ducks sake, one would think that there were 300,000,000 opinions on these subjects -- one per human in the country. What is this predilection that members feel that they must continue to add more rambling and off-topic (and occasionally incorrect) advice when the original question has been asked and answered?

Common sense (and probably the NEC, but I don't have time to find the citation) says do not add (or delete) a ground connection. Simpler than that: Why change the design of an electrical item, if you aren't qualified? There: simple.  

 

Last edited by Arthur P. Bloom

Arthur - I take your point but sometimes a robust discussion will bring up issues that others may not have considered.  It is a way of sharing knowledge and experience and finding answers to questions the OP did not know to ask.

With transformers there are many variable to consider since there is no fixed standard that applies to decades of evolving transformer design and train electronics.  Many old transformers do not meet today's safety and reliability standards so improvements are possible and regularly applied - in some cases by people who repair transformers and trains for a living.  For example someone using only one transformer may be surprised by the phasing issue if they expand their layout to multiple blocks and power sources.

Lionel did some funky things with some of their transformer models - terminal designation A, B, U etc. is one example.

"I take your point but sometimes a robust discussion will bring up issues that others may not have considered.  "

Absolutely.  I agree that a robust discussion is helpful.   But hand-waving and grasping for "facts" is not helpful, nor sometimes even healthy.

I wish I had a dollar for every time some well-meaning hand-waver gives the wrong electrical advice.

And as a licensed electrician, and a fire marshal, I wish I had a dollar for every chintzy power strip I've encountered.

BTW I admire your rhetoric: robust is a wonderful word that needs to be used more often. 

Personal experience.  I did a zener diode install identical to the above link on a ZW, and had to reverse the track leads in order for electronic horns to work properly.  

  1. Mitch 

Reverse the diode.   The stud type diodes can't be reversed easy, but often are made two ways, annode stud or cathode stud. (They should note that really; but your context was a mystery for me too.)

Personal experience.  I did a zener diode install identical to the above link on a ZW, and had to reverse the track leads in order for electronic horns to work properly. 

Then you used the wrong diode. You should use an Anode to Case diode with a 40 amp / 400 volt rating. THIS IS THE ONE YOU WANT. This is an NTE5991 Silicon Power Rectifier Diode.

Here's the procedure. The diode replacement process starts at 3 minutes into this video.

Last edited by Rich Melvin

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