Will AC-rated solid state relay work for DC application?

[giuseppe]

Assuming rated amperage is high enough? Also, will a 240v-rated AC SS
relay work in a 120 application? Thanks!

 

[Chris]

giuseppe wrote:

Assuming rated amperage is high enough? Also, will a 240v-rated AC
SS
relay work in a 120 application? Thanks!

Hi, Giuseppe. An AC SSR will turn on for a DC load, but it won't turn
off. That's because the triac (or inverse parallel SCRs) at the output
will only turn off at the zero voltage crossing of the AC line. That
won't happen with DC, so you'll be stuck with a one time latch that
will only turn off if you remove the power.

Use a DC SSR for DC. Usual cautions about current and voltage ratings
apply, of course.

Good luck
Chris

 

[Chris]

giuseppe wrote:

Assuming rated amperage is high enough? Also, will a 240v-rated AC
SS
relay work in a 120 application? Thanks!

Forgot to mention -- a 240VAC-rated SSR will always work for 120VAC.
If you look at the data sheets, they will list a minimum as well as
maximum load voltage. As I remember, that's usually around 24VAC for
the 120VAC SSRs and 48VAC or so for the 240VAC SSRs.

Good luck
Chris

 

[giuseppe]

Chris wrote:

giuseppe wrote:
Assuming rated amperage is high enough? Also, will a 240v-rated AC
SS
relay work in a 120 application? Thanks!

Forgot to mention -- a 240VAC-rated SSR will always work for 120VAC.
If you look at the data sheets, they will list a minimum as well as
maximum load voltage. As I remember, that's usually around 24VAC for
the 120VAC SSRs and 48VAC or so for the 240VAC SSRs.

Good luck
Chris

Thanks very much for the info, Chris. Just what I needed to know. I
really appreciate it!