Help Silicon Rectifier

[Ivan Vegvary]

Fixing old car battery charger. Do not want to buy new one because I need the 6 volt capability for my vintage motorcycle.

Need to replace a "button style" (Motorola MR2506) rectifier with a "stud mounted" one (Motorola 1N1190A) The stud mounted on has a higher rating.
Question: Data sheet says button battery cathode marked by "dot". Dot no longer visible on installed parts. Is it safe to assume that the wires from the transformer secondary lead to the Anode and the body of the "button style" (cathode) is pressed into the aluminum plate?
Thank you for your help.

[Mike S]

Do you know the make and model of the charger?

[Rheilly Phoull]

Only 1 transformer wire goes to the diode, the other elsewhere probably
an output terminal.

[John-Del]

The couple I putzed around with had two rectifiers. If there's another, check that. In any case, the cathode should go towards the positive lead.

[Ivan Vegvary]

Mike, the model is a Schauer CR612
2 button diodes. Case bonded to copper plate, lead goes to xformer.
On replacement diode (1N1190A) case is cathode.

[Ivan Vegvary]

Reilly, both diodes have a removable lead going to the xformer. The bodies are press fit into a copper plate. Do I simply unplug and check for current direction with ohmeter?

[tabb...@gmail.com]

can you not work it out by following wires & using a multimeter? Old chargers are exceedingly simple.


NT

[Sjouke Burry]

Just put it in, and then load the charger with a 12 volt headlight.
Then check polarity, and flip the rectifier connections if the polarity
is wrong.

[Ivan Vegvary]

Thanks all !!! Problem solved.
Disconnected good diode from circuit, tested and determined that the anode is connected to the transformer and the cathode is pressed on to the metal plate. Will order the 1N1190A stud bolt replacement. Inexpensive, probably less than the shipping cost.
Thanks again !

[John-Del]

Just make sure the diode you get is polarized the same. IIRC, those stud rectifiers were available with reverse polarity if ordered that way. Who knows if any of those made their way to the secondary parts market.

[tabb...@gmail.com]

In future you should keep at least 1 high current smpsu in your junk to get high i diodes from


NT

[Ian Field]

"Ivan Vegvary" <ivanv...@gmail.com> wrote in message
news:fd181a50-dda3-4926...@googlegroups.com...

In the UK, we have discount stores like Aldi & Lidl that do time limited
offers, battery chargers come around from time to time and sometimes they're
6V capable.

The David Silver Honda parts specialist allegedly has 6V capable Honda
branded Optimate chargers - but never on any of the occasions I tried to
order one.

[Rheilly Phoull]

On 30/04/2018 8:39 PM, Ivan Vegvary wrote:
> Reilly, both diodes have a removable lead going to the xformer. The bodies are press fit into a copper plate. Do I simply unplug and check for current direction with ohmeter?
>

Sounds like a half wave rectifier, there would be 3 wires from the
tranny. If the diodes are the same you would need to make sure they were
the same polarity as the previous diodes.

[Fox's Mercantile]

On 5/1/18 6:13 AM, Unlisted wrote:
> For a battery charger, you do NOT want a silicone rectifier, you want a
> SELENIUM rectifier. Silicone diodes are far too flimsy and cant handle
> the current load. Selenium rectifiers are made to handle all the current
> you can pump thru them. and are made to be abused without failing.

Good Lord, what fucking rock have you been asleep under for the past
fifty year?


--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com

[John-Del]

On Tuesday, May 1, 2018 at 7:46:43 AM UTC-4, Fox's Mercantile wrote:
> On 5/1/18 6:13 AM, Unlisted wrote:
> > For a battery charger, you do NOT want a silicone rectifier, you want a
> > SELENIUM rectifier. Silicone diodes are far too flimsy and cant handle
> > the current load. Selenium rectifiers are made to handle all the current
> > you can pump thru them. and are made to be abused without failing.
>
> Good Lord, what fucking rock have you been asleep under for the past
> fifty year?
>
>

Are you saying the advice to use selenium rectifiers "stinks"?

[Rheilly Phoull]

Heh, at least they had their own heatsinks :-)

[Ian Field]

"John-Del" <ohg...@gmail.com> wrote in message
news:679498a9-5ea2-4403...@googlegroups.com...

Rotten fish mostly.................

[bruce2...@gmail.com]

Well then, are you insinuating that the advice to use silicon rectifiers "stinks"?

[John-Del]

Perhaps I was just asking him to confirm or otherwise expand on his statement against using selenium in this application, or (more likely) was that I was tweaking the old guys in this forum who remember exactly what odoriferous emanations a selenium rectifier provides as evidence of it's failure..

[Rheilly Phoull]

Golly I hope we can get this all cleared for peoples state of mind !!

[Jon Elson]

Hmmm, I'd love to know where he recommends BUYING brand-new Selenium
rectifiers?

The powerhouse alternators that run without slip rings have a 10,000 Amp
rectifier mounted on the exciter. Yes, it is cooled by the hydrogen
atmosphere in the alternator, but that's a pretty hefty rectifier, less than
1 cubic foot, i think.

(For those who can't see the comma, that is 10 thousand amperes.)

Jon