re:relay help req.

Terry A wrote:
<snip>I wish to use <s> a ShopVac which the label says is 7amps with

>a 3hp peak. My s/s relay has a 16 amp rating and would like to know
>if it is safe to use on the vacuum?

Terry,

The major cause of failure for solid state relays is heat buildup.
This is OFTEN overlooked. So, the short answer is that a 16A ssr CAN
control a 7A load. But...

Solid state relays should be fastened to a suitable heatsink (use
heatsink grease) for best performance and life. You can generally use
a larger value ssr at a lower load to minimise heating. Sometimes,
depending on the circuit used within the ssr, this may not be a good
idea.

Hope this helps.

Ballendo

P.S. The term 'suitable' above refers to a larger than generally
thought necessary heatsink. Some people have a bad feeling re: ssr's.
In large part, this is due to the 'unexpected' failure of ssr's in
machines where the heat dissipation needs were not met!