SSR heat

Discussion of the physical aspects
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missing_link
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Joined: Sat Dec 20, 2008 2:44 pm

SSR heat

Post by missing_link »

How warm do the SSR's get? I have 2 20 amp SSR's that did not come with a heatsink so I mounted them to an aluminum plate I had. I am only running 12.5 Amps through them so I am just over 50% of thier capacity.

During a test where I let things run for a bit, I didn't notice them getting all that warm over the hour test I did and one of them was approaching the set temp so the PID function was switching on and off quite a bit.

Linc
np0x
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Re: SSR heat

Post by np0x »

twice in one day same post two different forums...hrm...interesting...
Heat is generated by all Solid State Relays in direct relation to the
amount of current being switched. Approximately 0.8-1.4 Watts
will be generated by the SSR for every Amp switched. This heat
must be dissipated as fast as generated otherwise the temperature
will increase until the relay fails. Approximately 90% of all problems
with relays are directly related to heat.
src: http://www.sprecherschuh.com/downloa...tions_v106.pdf

Also posted here: http://novahomebrew.com/showthread.php?p=7199#post7199
Check out the Brew Buddy for iphone controlling your bcs-460.
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ECC
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Re: SSR heat

Post by ECC »

You can also turn down the PID Sample Rate (Output Freq), which controls how often the output is switched. It defaults to a maximum of once/sec, but you can make that longer for less switching and therefore heat.
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