Does anyone have the schematic for the 3 diodes in a Delco Alternator?

These diodes are mounted into a heat sink (3 diodes). It looks like this ebay listing.

formatting link

Obviously these diodes are connected individually by the studs and nuts. But what does the other side of them connect to? Are they just connected to the heat sink?

Which end is anode / carthode?

I'm looking to replace the blown diodes in a 12V 50A automotive battery charger. (I only need 2 diodes). But I was told that alternator diodes are ideal for this application. If only I know how they are wired and the polarity. I'm sure the heat sink would be a plus too.

I'm a bit puzzled why they have 3 diodes on these "blocks". Normally 2 diodes are used, for a power supply, or four if it's a bridge rectifier setup. Three seems weird....

Thanks

Reply to
oldschool
Loading thread data ...

The alternator is 3-phase.

Reply to
DemonicTubes

...and check polarity with a meter...they come in both styles (metal case can be anode or cathode).

Reply to
DemonicTubes

And there are six diodes.

Reply to
tom

The 3-phase makes sense, but how are there 6 diodes? Do they have two of these heatsink blocks in the alternator or what?

Reply to
oldschool

Why don't you google "three phase alternator wiring"?

Reply to
tom

Den torsdag den 4. januar 2018 kl. 18.52.44 UTC+1 skrev snipped-for-privacy@tubes.com:

formatting link

Reply to
Lasse Langwadt Christensen

Automotive alternators are three phase.

Reply to
krw

Thats what I was looking for..... Thanks!

Reply to
oldschool

These won't work in your application. You say two diodes in the charger, an d that probably means full wave rectification of a center-tapped transforme r. The diodes for alternator have either all the anodes connected together (negative ground) or all the cathodes connected together (positive ground). You would be better off buying individual stud mount rectifiers. Something like this

formatting link
.

Reply to
bloggs.fredbloggs.fred

Give that another think. In a center tapped transformer application the two diodes will have either their anodes or cathodes connected together. He could use the block shown by connecting two of the studs to the non-center tapped transformer connections, treat the center tap as ground and using either the positive or the negative terminal of the diode block depending on what polarity he chooses, or both!

--
Rick C 

Viewed the eclipse at Wintercrest Farms, 
 Click to see the full signature
Reply to
rickman

ote:

s.

ry

r

, and that probably means full wave rectification of a center-tapped transf ormer. The diodes for alternator have either all the anodes connected toget her (negative ground) or all the cathodes connected together (positive grou nd). You would be better off buying individual stud mount rectifiers. Somet hing like this

formatting link
.

two

r

on

One diode in the block goes unused and the diodes that are used have a much smaller forward average current rating than the ones I noted. Your money g ets you less diode with the misused generator block IOW, significantly less , and all you do is take up a lot of space unnecessarily.

Reply to
bloggs.fredbloggs.fred

snipped-for-privacy@tubes.com prodded the keyboard with:

A vehicle alternator is a three phase generator! One diode for each phase.

--
Best Regards: 
                      Baron.
Reply to
Baron

TWO diodes for each phase. It's full-wave. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
 Click to see the full signature
Reply to
Jim Thompson

Is there a reason for the 3 phase? Cna they get more amperage that way, or what? Just curious.....

Reply to
oldschool

3 alternator rectifiers are used for the wye winding; the heatsink is the common ground. Now you know the "why" of it (could not resist).
Reply to
Robert Baer

Duh ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
 Click to see the full signature
Reply to
Jim Thompson

and less ripple,

formatting link

Reply to
Lasse Langwadt Christensen

Yes, it's the most efficient use of copper. The same reason power distribution is almost always 3-phase.

Reply to
krw

Jim Thompson prodded the keyboard with:

Thanks. Yes, I should have said "diode pair for each phase"

--
Best Regards: 
                      Baron.
Reply to
Baron

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.