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Old 01-15-2017, 02:06 PM
Rufus Rufus is offline
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Default Heat sinks

Hi all:
I will have my 150 amp diodes in about a week and I was wondering, does the heat sinks have to be made of aluminum? I have given some thought as to using just plain mild steel and tack welding the heat sinks together. My nephew who works in the IT field tells me that heat sinks are made of either aluminum or copper. Can I use mild steel?

Thanks
Tim
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Old 01-15-2017, 02:22 PM
yooper yooper is offline
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I don't believe steel would transfer the heat fast enough , I've been a industrial electrician for 40 years and have never seen anything but aluminum used .
Also remember to use silicon heat sink compound when mounting the studs to the aluminum .
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Old 01-15-2017, 02:22 PM
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Of course steel will work as a heat sink, but it would take a much better engineer than me to tell you if it's sufficient compared to the vastly greater thermal transfer speed of copper or aluminum. You might be able to make up for it in the design with greater mass or surface area.
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Old 01-15-2017, 02:44 PM
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Another thought that has occurred to me is to use heads off of small engines. Some are aluminum and some are cast iron although the aluminum heads dissipate heat more readily. Here is a heat sink that I am considering:

https://www.zoro.com/omron-relay-hea...00/i/G2608715/

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Tim
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Old 01-15-2017, 03:01 PM
Lew Hartswick Lew Hartswick is offline
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Are you planning on one each for the diodes or thinking of all 4 on one of those?
If you'd give me a sketch of the circuit and data on the diodes load etc. maybe I could be a bit of help. I did this sort of stuff for a lot of years.
On the subject of material, NO steel is not going to be a suitable for a "heat sink" for the kind of use I think you are talking about.
Another thing to consider is the orientation of the sink (actually a radiator). If you don't use forced air then it should be mounted with the fins vertical to allow convection to help and don't block that flow.
...lew...
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Old 01-15-2017, 03:18 PM
yooper yooper is offline
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For a full wave bridge rectifier he will need two separate heat sinks if he has 2 forward and 2 reverse diodes , if the diodes are all the same polarity he will need four separate heat sinks .
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Old 01-15-2017, 03:21 PM
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Quote:
Originally Posted by yooper View Post
For a full wave bridge rectifier he will need two separate heat sinks if he has 2 forward and 2 reverse diodes , if the diodes are all the same polarity he will need four separate heat sinks .
Yooper could you draw up a bridge rectifier explaining both?
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Old 01-15-2017, 03:24 PM
Rufus Rufus is offline
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Quote:
Originally Posted by Lew Hartswick View Post
Are you planning on one each for the diodes or thinking of all 4 on one of those?
If you'd give me a sketch of the circuit and data on the diodes load etc. maybe I could be a bit of help. I did this sort of stuff for a lot of years.
On the subject of material, NO steel is not going to be a suitable for a "heat sink" for the kind of use I think you are talking about.
Another thing to consider is the orientation of the sink (actually a radiator). If you don't use forced air then it should be mounted with the fins vertical to allow convection to help and don't block that flow.
...lew...
So, that knocks the mild steel idea out of the equation. On one heat sink there will be two diodes mounted but the other two diodes will go on their own heat sinks. I plan on using a small fan for forced air heat dissipation. I can't seem to get the 1NXXX number of the diode to provide the spec sheet, however when I get the diodes in I will give it then. Here is the ebay address for the diode.

http://www.ebay.com/itm/150A-POSITIV...-/261092065367

Here is the link to the diagram of the rectifier that I will be using...

http://www.diracdelta.co.uk/science/...l#.WHvX9tQrLGg


Thanks
Tim

I figure that 150 amps will be bit enough for all my welding needs.

Thanks
Tim
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Old 01-15-2017, 03:35 PM
Rufus Rufus is offline
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Here is a sketch that I drew up as to how they would be connected mechanically. As you can tell, the bottom two will go on one heat sink. The other two on their own separate sinks. The "doted cap" is a filtering cap that I might add later.

Thanks
Tim
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Old 01-15-2017, 04:25 PM
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How do I upload a image from my computer ? The insert image icon wants to do it from a url link ?

Quote:
Originally Posted by digr View Post
Yooper could you draw up a bridge rectifier explaining both?
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