40 Amp Stud Mount Diode

[kfrazie1]

Looking at using an NTE5987 silicon power rectifier diode for a pedal powered generator application. It is is rated for 40 A and will prevent current from flowing from the battery back to the generator. I plan on bolting it to a heat sink. Have any idea on what the difference between an "anode-to-case" and "cathode-to-case" means.

[retched]

The part that is bolted down is the "to case" The tab on top is the other.

I.E. Cathode to case, the threaded part at the bottom that bolts down is the cathode.
The eyelet at the top would be the anode

Anode to case, the threaded part at the bottom that bolts down is the anode. The eyelet at the top is the cathode.

[Bill_Marsden]

Between the both of them you could have a full wave bridge rectifier.

[kfrazie1]

is there any reason why i would want one over the other?

[t_n_k]

As Bill implied - you may have a situation where you want to have several devices connected at a common node - such as at either the +ve or -ve side of a bridge rectifier comprised of discrete power diodes of this type.

[BMorse]

You would probably want to use one that can be bolted to a grounded case which would be the Anode to Case, this way you wouldn't have to isolate it from the case if it was the other way around or else you will have a direct short from + to -.

I used a Anode to Case for my Windmill generator since the charging circuit was grounded to the case and I wanted to bolt the heatsink to the case... If I would have gotten the cathode to case, I would have created a direct short from the positive coming from the generator to the grounded heatsink...


B. Morse

[t_n_k]

Mind you - nowadays, with the increasing use of fully modular units such as single or poly-phase rectifier bridges, the need to think about such matters is declining.

[eblc1388]

Finding a suitable nut or tap to mount the thing will drive one mad.

[rjenkins]

I keep a stock of 35A 1200V bridge rectifiers. For some reason these are very cheap (like $5) from several suppliers and very useful whenever a high powered rectifier or diode is needed.

They have four 1/4" push-on terminals and an isolated metal base with a single fixing hole, so they are also very easy to mount.

You can use them as a 'single' diode by connecting both AC teminals together as one side and one of the DC teminals as the other. (That puts two of the bridge diodes in parallel).

If you've not bought a power diode yet, have a look at what your suppliers can offer.

[BMorse]

Originally Posted by eblc1388

Finding a suitable nut or tap to mount the thing will drive one mad.

Mine fortunately came with the nut and lock washer, and it actually uses a standard ANSI threaded tap, I believe 3/8-16 or 5/16-18 one of the 2 can't remember off the top of my head....

Mind you - nowadays, with the increasing use of fully modular units such as single or poly-phase rectifier bridges, the need to think about such matters is declining.

These are not bridge rectifiers, they are a single blocking diodes..... used to prevent powering the generators from the battery banks....

B. Morse