Sign up

[billyO]

Hello all.  I'm upgrading my forge with a PID controller and 2 different SSR set-ups have been suggested:
a) 25A SSR (SRDA25) with a heat sink (HS25) or
b) 40A SSR (SRDA40) without a heat sink. 
Option (b) would be a little cheaper and require less room, but I'm more interested in safety and longevity of the components. 
Thank you.

[billyO]

Nevermind, I got my answer.

[Kkane]

Option b is incorrect. If your load/heating element is over 6A, you have to use a heat sink together with your SSR. If your load is within 25A, you can use 25A, or 40A SSR for better lifetime. But 25A heat sink is needed anyway.