Cheap SSRs

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Yummyrum
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Cheap SSRs

Post by Yummyrum »

I bought an SSR 60 DA to use with my Auber DSPR 1 and consequently also my one Arduino power controller .

Well it worked for a while , but then , on several occasions if run at full power , when I turned down the power control , it still sent full power to the element .
Switching it off and letting it cool down a bit and it was good to go again .

I’ve been using it back on the DSPR 1 again lately . I noticed that the LED on it was dead or flickering erratically and intermittently it would start working again .

Obviously it has finally shat it’s self so I was curious what was in it .
A quick tap with a chisel and hammer on each side and the top pops off .
IMG_3642.jpeg
There were two devices screwed to the heatsink . It turns out that they had used two BTA24-800 TRIACs in parallel .
IMG_3644.jpeg
These are rated @ 25A 800v each . So even with two , it was only 50amps and not 60 :thumbdown:
IMG_3646.jpeg
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It is also bad practice to parallel Triacs anyway as one will share most of the load and the other may not even trigger on .
So it was a cheap bad design .

Incidentally , it uses the MOC 3063 zero-crossing optocoupled triac driver . The black paint is an isolation barrier paint .It is not a sign of overheating .
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IMG_3642.jpeg
Anyway , buyer beware . I thought I was getting a Fotek SSR but I got a very obviously bad copy . My god , how did I miss that the name Fotek was spelt wrong .

I forgot to mention , when I first bought it and placed it in the main heatsink that it was “woobly” . The heatsink plate on the SSR was not perfectly flat and there was almost 0.5mm warp on it . So I had to grind it flat on my Lannisher to get an intermit contact on the heatsink . Hate to imagine how quickly it would have died if I just slapped in some heatsink compound and screwed it down .
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