I am using Solid state relays to On/Off heaters so as to control temperature. In case if heaters get short,immediately the Solid state relays ( SSR ) also gets short and I need to change new one.Even though I have Fuse protection the SSR and Fuse gets blown. Since the Cost of SSR is high,I have so many troubles.
So any one Please suggest some ideas to prevent SSR failure.Is there any protection like Varistors , RC circuit to prevent this?????
If your heaters keep shorting you need another make. You need the right type of fuse ie thyristor semiconductor fuses these are also expensive.
Use a fuse whose I-squared-T rating is less than the SSR's semiconductor device I-squared-T rating. Also use what is known as a sub-cycle fuse. If you size the fuse this way and it's continuous rating turns out to be less than the heater's normal current, your SSR is too small.
John
Why have you posted this 5 times ?
On Tue, 10 Jan 2006 14:57:10 +0000, via , Pooh Bear spake thusly:
You must be mistaken. I only see it posted four times. :-)
How big a heater? 1500 watts? What kind of heatsink is the SSR mounted on? Why are your heaters 'get(ting) short'? Others have pointed out that THAT should be addressed -- like now. What is the rating of the SSR? Is there a largish motor as part of the heater that could have a large inrush?
In general, SSRs are fairly tough to blow up so what are you actually doing to it?
GG
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