ssr ratings and resistance loads

[paulwd]

hi all

I wish to use a ssr to switch an element in a 240v coffee machine. Load is 4000w. I would like to know what rating ssr to use. Coffee machines are rather warm environments (at least 40-50C) and I understand that ssr efficiency is related to their ability to dissapate heat.

so, would I get away with a 25A + heat sink?

many thanks

paulwd

 

[Diver300]

4 kW for a coffee machine seems a lot. That is about 17A.

A 25 A SSR should be OK if bolted to a good heat sink. However, a quick look on Farnell showed a 25A ssr for £20 and a 50 A one for £27, so for a one-off it may not be worth pushing it.

You'll still need a good heat sink.

 

[paulwd]

thanks, I'll go for a 50A.

Yup, 17A draw. Big machines can get up to 6kW for their boiler elements.