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Strange Glass (not tube) selenium rectifiers

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Matt Edwards

Sun Jul 04 2010, 05:25AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

Anybody interested in these? Labeled 123D Federal selenium rectifier. I don't have any information other than that...
They do look pretty "vintage" and cool. I bought them with a handful of glass non inductive resistors. Didn't realize that they were rectifiers.

803

Wed Jul 07 2010, 09:00PM

Registered Member #2807 Joined: Fri Apr 16 2010, 08:10PM
Location:
Posts: 191

What do you want for them? Shipping is just a postage stamp and a bubble mailer.

Matt Edwards

Wed Jul 07 2010, 09:35PM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

Trade would be preferred. Honestly i dont know what they are worth. I am looking for coil stuff and a matching pear of heatsinks large enough for mosfets. Name a price or trade item that would be worth it to you.

I was thinking that they would go nicely on a VTTC!

803

Thu Jul 08 2010, 10:11PM

Registered Member #2807 Joined: Fri Apr 16 2010, 08:10PM
Location:
Posts: 191

Well your in luck! A 1/2 a year ago I took apart a ATX. It had preaty big heat sinks. They arn't exactly the same and they have some light scraches that can be painted over with some AL paint. The holes are around 3/4 inch and there 3 of them each. What do you think?

Matt Edwards

Thu Jul 08 2010, 11:42PM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

Have a pic? Im not really looking for a profit. I got them cheap. I would just like to see them put to good use and maybe help out someone in the HV community.

Btw, any plans for them?

803

Fri Jul 09 2010, 01:35AM

Registered Member #2807 Joined: Fri Apr 16 2010, 08:10PM
Location:
Posts: 191

Well I will tell and ask some questions

1. Se. Diodes arn't the powerful. they are realy made of plates. A one inch plate is good for 100 miliamps. these were used in stuff like photo copies and other low current, high voltage uses so I'm not sure if they can stand the 500 miliamps of a MOT. They also fail and go leaky after a while so this one might not work. If this was like, a couple inches thick thy would might be useful, but they wouldn't stand the power, I think, I don't know the size of these things.

2. I am making a VTTC right now (I will prove you wrong Herr Zapp!!!!~:-( ) , but my soldering iron broke so I will have to buy one.

3. If I can't find a data sheet, (I think I will, The people at the ARF, are great, REALY NICE TO ANYONES IDEAS, and I think they will come through) I will put it on display with my colection of antique vacuum tubes.

3. If I find a a data sheet, Prehaps I will use them to rectifie a AC Flyback< there isn't mich you can do with these things anymore.!sad

4. When I said 3/4 inch holes, I meant 3/4 in from the bottom of the heat sink to the hole, the total height of the sink is 2 1/2 inches.

5. Yes, I do collect antique radio/ vacuum tubes/ electronics, ARF, Antique radio forum:-D

6. Pic tomorrow

Cheers,

Paul

Matt Edwards

Fri Jul 09 2010, 02:04AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

Well, I looked at some of your old postings and have determined that you seem like a nice guy. I will find out what shipping is and you can have them for what I paid $5. Is there a way to test them to make sure they work? I would assume that since they were incensed with glass, and selenium releases vapors when they go bad, that they would be discolored if damaged?

Anyway, I originally purchased them from the local navy surplus without looking carefully and assumed that they were the non-inductive glass resistors that I purchased in the past.

If you want them let me know.. Also, please specify a preferred carrier and a zip code so that I can determine shipping cost. I will make sure that they are packaged safely. If you do decide that you would like them then send me a private message with your info. And you must promise to send me pics if you use them in a project!

Nicko

Fri Jul 09 2010, 05:33AM

Registered Member #1334 Joined: Tue Feb 19 2008, 04:37PM
Location: Nr. London, UK
Posts: 615

Oidium45 wrote ...

...Anyway, I originally purchased them from the local navy surplus without looking carefully and assumed that they were the non-inductive glass resistors that I purchased in the past.
...

Just a quick couple of points - Selenium is very nasty stuff - don't feel the urge to open these up to have a look.

Selenium rectifiers are prone to failure - they should have a forward drop of around 7 volts - if you set up a current limited 20V supply and allow say 50mA through the rectifier, measure the drop - if its significantly more than 7V, the rectifier may well be dead.

Just for the record, "Federal" was a well known manufacturer of these and there is data all over the web. Most antique radio types will tell you to leave these in kit if you find them and they're not dead - because of their characteristics, they also have a current-limiting action, so (in valve kit at least) if one fails you shouldn't just replace it with some convenient silicon option like a 1N4007 unless you also place a resistor in series too.

Cheers

803

Fri Jul 09 2010, 10:00PM

Registered Member #2807 Joined: Fri Apr 16 2010, 08:10PM
Location:
Posts: 191

Pics of heatsinks

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