diode for 12v conversion

mdaitc · Dec 23, 2008

Hi,

the last step i've got to do on my 6V +ve gnd to 12V -ve gnd on a 330U is the diode from the alternator...

Just wondering what other people have used for this diode - would a Borg-Warner SC113 diode be suitable (have one handy), and if so, what's the wiring diagram going to look like (it's got 4 terminals).

Failing that, what's a good part to get instead?

Thanks!

Janicholson · Dec 23, 2008

We need more info as to alternator type. A 3 amp diode with 1000PIV rating will do well, As will a diode robbed out of a old alternator diode pack. The 4 terminals has us confused, as many four terminal alternators are external voltage regulator types from the 60s or early 70s. these are quite different, (they work but are more difficult to install. JimN

JMOR · Dec 23, 2008

(quoted from post at 22:13:52 12/23/08) We need more info as to alternator type. A 3 amp diode with 1000PIV rating will do well, As will a diode robbed out of a old alternator diode pack. The 4 terminals has us confused, as many four terminal alternators are external voltage regulator types from the 60s or early 70s. these are quite different, (they work but are more difficult to install. JimN

He probably means this 4 terminal diode & plans to use it in the excite terminal of a 10-SI, but he needs to confirm.
http://shopping.msn.com/specs/borg-...ext=itemname:borg-warner-sc113-diode-assembly

old · Dec 23, 2008

If your talking about the diode that you use in the #1 terminal wire so you can stop the engine I use Radio shack #276-1661. A pack of 4 will cost you about $2.50 plus tax and I keep them on hand all the time just for that
Hobby farm

Hayfarmer · Dec 23, 2008

I got a diode at NAPA, cost a little more but set up to put into the line.

Anonymous-0 · Dec 23, 2008

Should be easy to do, just take an ohmeter and test the terminals till you find the pair that goes one way and not the other (when you switch the black wire with the red) I have done this before, I just by the cheapest diode they have at Napa, for a Delcotron.

Bob M · Dec 23, 2008

I've gotten excellent service from the 1N4004 (1 amp, 400 volts PIV). Price is right too - $1 at Radio Shack, or 10 for $1 at the local electronics parts house.

mdaitc · Dec 23, 2008

Hi,

i was referring to the diode that (as Old puts it) "diode that you use in the #1 terminal wire so you can stop the engine"

I just happened to have a diode laying around from something i picked up in a box from a sale a while back, and wondered if that would work - but i'd rather get the correct part.

Yes, JMOR - that is the diode that I have, and was trying to figure out if it would work in this particular application.

Thanks for the part numbers of the other diodes - i'll look at the specs on them!

Thanks!

Wild Bill · Dec 23, 2008

No not that!

John T · Dec 23, 2008

If you using a diode to prevent ignition run on after the ignition is turned off as is done when wiring a GM 10 SI Alternator to excite the lil No 1 side terminal, I recommend instead a current limiting safety resistor anywhere from at least 10 ohms up to 100 ohms will work or else a small incandescent lamp which also serves as an "idiot light" to indicate charging..... About any diode will work provided its DC voltage withstand rating (PIV) is 100 volts or so and around 3 amps or so, although I like the higher amps and/or PIV simply cuz they may have bigger easier to wire leads....wire them - cathode end towards alternator...

John T

mdaitc · Dec 23, 2008

Thanks John T.,

you confirmed my other direction - thinking along the lines of the bigger the diode the better to an extent, i've just found the 1N5404 - a 3A 400PIV

JMOR · Dec 23, 2008

The 1N5404 will be fine, as would your SC113. In the alternator, it supplies the field near full time & in the #1 Excite lead it will do the same , but only momentarily until the diode trio takes over. There are 3 diodes in your package of which you would only be using one (two spares). See pics for photo of same and diagram for schematic of same (diode trio).

NawlensGator · Dec 24, 2008

I used radio Shack 276-1661 with no problem. White band faces alternator.

diode for 12v conversion

mdaitc

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old

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Hayfarmer

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Anonymous-0

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mdaitc

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