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Heat Sinking a Rectifier - Questions...


By xeroid, Section Homebrewed Electricity
Posted on Fri Apr 16, 2004 at 11:00:24 AM MST
Best hardware to use...??? Suggestions...???

Hi folks.

I need to pick some of those brains out there.

I just received 10 rectifiers, (600V, 35A) and I want to use a piece of 4" aluminum tube (about 1/8" thick) as a heat sink.

I will cut the "heat sinks" out of the tube and cut "fins" into them to dissipate heat from the rectifiers.  I will mash a flat spot into each where the rectifier is bolted on for maximum contact and heat transfer (with some thermal conducting grease) from the rectifier to the heat sink.

My question is, what type of BOLT do I use?  I am not sure if there could be a problem with dissimilar metals creating corrosion from electro-plating.  Should I use a zinc plated bolt?  Stainless steel?  Brass?  

Please help.  I don't want to ruin the rectifiers.

Thanks in advance.
Heat Sinking a Rectifier - Questions... | 8 comments (8 topical)

Re: Heat Sinking a Rectifier - Questions... (none / 0) (#1)
by RobC on Fri Apr 16, 2004 at 05:32:52 PM MST

Seems like a lot of work. I just use a plain old piece of 18 to 14 sheet aluminum
or channel some heat sink compound and screw them on with whatever bolts I can find.
I am assuming these are fullwave bridge rectifiers. If they get hot use a bigger piece of aluminum. RobC


Re: Heat Sinking a Rectifier - Questions... (none / 0) (#4)
by TomW on Sat Apr 17, 2004 at 07:06:16 AM MST

RobC;

Yeah, I do the same. I get scrap aluminum from behind the shears at the ironmongers shop. Big box of odd pieces for a couple bucks. I use the strap type pieces as 2 blade hubs for Jerry Blades too. Seems like most factory built stuff uses non ferrous screws and nuts [non magnetic] so either stainless or plated brass but I just use whatever is in the fastener jar that fits. No problems so far.

Cheers.

TomW

The Truth is the Truth, even if no one believes it; and a lie is a lie even if everyone believes it


[ Parent ]



Re: Heat Sinking a Rectifier - Questions... (none / 0) (#2)
by drdongle on Fri Apr 16, 2004 at 06:50:38 PM MST

The bolts arn't realy an issue, us what ever is cheepest.

Dr.D
Carpe Vigor, Dr.D



Re: Heat Sinking a Rectifier - Questions... (none / 0) (#3)
by pwmvsi on Fri Apr 16, 2004 at 08:22:07 PM MST

Using a flattened piece of tube is not a good way to go because of poor contact.  The plat idea is premo...   Make sure you got the goop to insure heat transfer.

Good Luck

WS



Re: Heat Sinking a Rectifier - Questions... (none / 0) (#5)
by monte350c on Sat Apr 17, 2004 at 10:42:01 AM MST

I've been using the heat sinks off computer CPU's - the older type found on 486 machines. Found a bunch at the surplus store for 50 cents each. The side that used to go on the computer chip is very flat, and the other side has lots of fins. They are made from aluminum. I just drill a hole in the middle, put some heat sink guck on them, and bolt them together.

Works pretty well and it's also pretty cheap!

Ted.



Re: Heat Sinking a Rectifier - Questions... (none / 0) (#6)
by nothing to lose on Sun Apr 18, 2004 at 02:06:09 AM MST

Yea those are great heat sinks, computers have alot of goodies in them :)

I just scored a bunch of free power supplies, suposed to be junk, grabbed em before they hit the trash. Caps, transformers, transitors, 2 large aluminum heatsinks etc..

I'm going to test before stripping them, some may need a fuse or even actually work. These guys are nice, but aren't the best at figuring out whats wrong with stuff.

I use Artice Silver for heatsinks on alot of stuff, one tube for my cpu's lasts forever! They also have the same type stuff that is more of a glue to bond the sinks and parts together, no holes or screws needed. Thinking about getting myself a tube of that too.
.
nothing to lose

Spelin and tpying are my strong points, not electronics.



Re: Heat Sinking a Rectifier - Questions... (none / 0) (#7)
by xeroid on Mon Apr 19, 2004 at 01:40:09 PM MST

Thanks guys.

I think I'll still try mashing a flat on the piece of aluminum that I've got, just 'cause it's what I have on hand.

I'll definitely get some heat sink goo though.

Any ideas as to where I could get the stuff cheap in Canada?
Regards, XEROID.



Re: Heat Sinking a Rectifier - Questions... (none / 0) (#8)
by Nando on Sat Apr 24, 2004 at 09:55:03 PM MST

Question:

What is the current going through each diode ?.
How many diodes ?.

These 2 questions determine what type of heat sink you need ( Volume, fins areas and some other factors.

The CPU shown in one of the replies to your message is good for 15-20 watts with a small blower on it, without it just 3-5 watts.

Regards

Nando



Heat Sinking a Rectifier - Questions... | 8 comments (8 topical)
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