Quote:
Originally Posted by PhredAre
I question these failures that are happening in the first few minutes of energizing the oven, and laying blame onto the lack of a heatsink. Unless the SSR is pulsing at the begining of the heat cycle it dosn't generate much heat. Further more it takes time for the heat to migrate into the heat sink and transfer into the air. My thought is the SSR is defective if it fails in the first few minutes of use, provided its not overloaded. When a new SSR is purchased with a built in heatsink we are probally purchasing a better quality device. That old saying applys ;" You get what you pay for ", Fred
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No... the problems are due to lack of a proper heatsink.
SSR's DO generate a lot of heat. And they generate the most heat when at 100% duty cycle, not when pulsing.
If you look at spec sheets, they all say that a heat sink is reccomended for all appliacations and is required if running anything more than 20% of the SSR's rating. At more than 75% of the rating, you need a very good heat sink. Typically a large portion of an SSR's datasheet is dedicated to heat-sinking.
For the record, I also used an old CPU heatsink and cooling fan after burning up my 1st SSR due to improper heat sinking. Works absolutely perfect and the SSR doesn't even get warm anymore.