EHHA Rev A - Interest Thread
Sep 17, 2010 at 7:48 PM Post #481 of 1,752

jdkJake

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So, not sure if you can tell or not from the photos. The smaller of the two boards, the one the boards are actually mounted on is 12inches by 12inches.

That should give you some idea of scale. It is also the exact size of the Par metal case I am considering. :wink:
 
Sep 17, 2010 at 9:20 PM Post #489 of 1,752

jdkJake

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Okay, seems to be warmed up again. I had to shut it down to use the stove to make dinner. :wink:

In any case, the heater voltage and MOSFET bias is steady as a rock. No issues there. As for the heatsinks, keep in mind these are 2 inch heatsinks and room temp is 77 degrees F (25C). Measure is at the top center of each heatsink:

MOSFETS: ~45 to 47C
PS: ~40 to 42C
Heater PS: ~35C



 
Sep 17, 2010 at 9:35 PM Post #490 of 1,752

cobaltmute

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Quote:
Okay, seems to be warmed up again. I had to shut it down to use the stove to make dinner. :wink:

In any case, the heater voltage and MOSFET bias is steady as a rock. No issues there. As for the heatsinks, keep in mind these are 2 inch heatsinks and room temp is 77 degrees F (25C). Measure is at the top center of each heatsink:

MOSFETS: ~45 to 47C
PS: ~40 to 42C
Heater PS: ~35C


Seems not too bad - especially for the PS considering that is a 32V transformer as opposed to a 30V.
 
Current outside temp is 11C.  I just need to open the window to keep it cold.
 
Sep 17, 2010 at 10:14 PM Post #491 of 1,752

jdkJake

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Lucky dog. We have the AC cranked to get it down to 25C. Brutal summer this year after a most cold winter (at least for Florida).

The power supply is barely breaking a sweat. The torrid itself is pretty warm. The flat washer on the center screw that holds down the top plate is running about 51C.
 
Sep 17, 2010 at 10:51 PM Post #492 of 1,752

jdkJake

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Time to call it a night. I didn't get to measure the DC offset as I said I would. As they say, tomorrow is another day. I will do it then and post the results.
 
Thanks to all for the kind comments regarding the build. It was a fun build. I really had a blast!
 
Couple of parting shots (as I cannot help myself
wink_face.gif
)...
 

 

 
Sep 17, 2010 at 11:05 PM Post #493 of 1,752

fishski13

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Jake,
looks great!
beerchug.gif

 
Sep 18, 2010 at 5:50 AM Post #494 of 1,752

stixx

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Yes, excellent work...
 
The measured temp on the toroid hold down screw and washer keeps me thinking... will overspec the transformer to 400mA most likely...
51C is a lot and you have yet to case it up.
 
Sep 18, 2010 at 7:20 AM Post #495 of 1,752

fishski13

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Quote:
Yes, excellent work...
 
The measured temp on the toroid hold down screw and washer keeps me thinking... will overspec the transformer to 400mA most likely...
51C is a lot and you have yet to case it up.


screwing the TX into aluminum vs wood chassis will bring the temp down a bit, but yes, 51C is quite warm.
 

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