Hi Guys....

On the bench today is a Model 1066 train transformer from Lionel. What can that copper oxide rectifier be replaced with? The transformer was under water. The transformer at idle is drawing about a 1/4 amp after letting it dry out for two weeks w/heat. While it's all apart, the rectifier looks a bit skanky and I'd like to replace it with another type rectifier....

Any suggestions?....

Tnx...
...Jim

Best to use the Lionel part. On eBay for $7 - $9. Search for Lionel rectifier disc.

Got it Mort!.....

Thanks for the tip......

But now it's got me wondering.....what could replace that rectfier if the replacements weren't around?

Agn, tnx Mort...
...Jim

Good question. I'm not even sure how that disc was made. I rebuilt my transformer a couple of years ago and was quite amazed on how it went together, especially on how the transformer made the whistle work.

Why not just use a 10 cent 1N4007 or a 30 cent 1N5408 diode? Is there a real need to preserve an authentic look? Functionally a modern diode will work fine.

Rich

I thought of that Rich.....

...or maybe a bolt-type rectifier would be more appropo.

I do know there is a DC voltage impressed on the AC rails for that whistle to work. Unlike the AC action needed to operate the original E-3 reverser mechanisms on the locomotive. (on-off-on)

Interesting. I did a google search and found this:

http://ontracktrestle.com/diode-sell.html

There's links at the end for other Lionel transformers. Looks like a stud rectifier is the way to go.

Here's the diode (for the part number):

http://www.allelectronics.com/make-a-store/item/1N1190AR/40-AMP-600-VOLT-RECTIFIER/1.html

It's $3.50 at All Electronics or $6.80 at Mouser

Could a selenium rectifier be used?

It would take a pretty big selenium rectifier. 1 inch plate selenium was rated under 100 mA.

How about this?

http://www.lioneltransformer.com/diodes

Using a 40 amp stud diode is serious overkill, but at least you can used the bolt mounting hole.

Rich

i put in a big diode in mine.

I would think you would need a pretty hefty selenium and would not have space for it. Most of the old copper disks I've encountered were subject to some heavy currents. The little seleniums we see in AC/DC sets are only good for a few hundred milliamps.

All good ideas.....

heh...one of the fun things to watch, when I was a tyke, was the shower of sparks that were produced when a Lionel loco or rolling stock derailed. Now, I know that must've put some awful load on the transformers...and, of course, this would happen just as you were whistling past a grading! So I'm wondering whether the copper oxide rectifiers were used because they could better stand the momentary current overload much better than a bolt on or axial rectifier. Not to say that with the proper fusing you couldn't save the later style rectifiers, but you'd still end up taking the transformer apart to renew the fuse.

Copper oxide was used because there were no silicon diodes when those transformers were designed. Even selenium was new technology at that time.

Rich

True, but the technology for electric train transformers did not change even after those improved, less expensive replacements became available. Perhaps this was an illustration of my old signature line, "There is no such thing as a change for the better."

During the 1970s, while at Westinghouse Semiconductor, we sold tens of thousands of modern silicon diodes to Lionel and Model Rectifier.

No one make copper oxide anymore.

Rich

I was under the impression that Lionel used low voltage AC for the propulsion motor and added a dc bias on the tracks to blow the train whistle - so that the rectifier would see a low duty factor.

--Chuck

It probably does.....

Not having a whistle assy in front of me, I'm wondering if it's a DC relay in the whistle assy that will close an AC switch to operate the whistle.

That's exactly what happens, Jim. The whistle itself is an AC motor driving a fan attached to the armature shaft. Air blown through the whistle chamber produces the sound. Consequently, the whistle works best at wide open throttle.

Bruce Webster

All depends on what type lionel you are working on. The tender whisltles are driven with an ac motor identical to the locomotive itself, these are acivated by a relay. The horns use a 1 1/2 volt flashlight battery to power the horn, and that is activated by a low dc current applied to the track that pulls in a relay, that acts as a switch to apply the flashlight battery voltage to the horn. All of the diesels are like that.

forgot to mention - see "kuprox" for some neat info on the copper disks. Created by the Liebel Fleishmann company and patented, the patent rights were sold to Kodel Radio and the name Kuprox was applied. Kodel used these in all of their 1930's socket power and charger devices. (Automatic electrical devices Co)"