Anyone have any experience with SSR’s? I plan on using one with 120 V mains to heat an 800 W bed heater. I was planning on mounting it directly to an acrylic sheet but I’m worried about how hot it might get.
No experience (yet) but every installation I’ve seen on the 'net shows a heat sink of some soft, often as simple as a sheet of 4-5 mm aluminum or a finned type of heat sink.
If you try acrylic, put a camera on it and record time lapse so we can enjoy the melting or combustion result.
I use 220V 750W heater with genuine Fotek 25A attach to aluminium plate, I feel almost no heat at all on that plate.
SSR only turn on while heating up about 3 minutes then it just flashing every 2-3 seconds the rest of the print.
But if you really worry maybe just add a spacer between SSR and acrylic sheet.
@Fred_U I was checking out Tom’s video and he says they usually don’t need cooling https://youtu.be/TiEwNf1H_Tc?t=188 (timestamped URL , no neeed to seek through the video).
@Dont_Miyashita I guess I’ll try without a spacer the first time I power up the bed and watch closely, if it gets too hot I’ll add a spacer.
You can pick a ssr’s with a much higher current rating to help cut down on how much heat is generated. You will pay a little bit more for the ssr but it’s a nice safety margin to have.
I have been using opto 22 ssr’s for my build and have really liked them, good pricing as well on Amazon.
Use an actual omron SSR. Just search youtube for how underbuilt and underspec’d the fotek are and you will see why.
Was planning to use Crydom, anyone know anything about them?
https://www.digikey.com/product-detail/en/crydom-co/D2425/CC1006-ND/139477
Crydom makes a very nice ssr, like omron and opto 22 they are a true industrial component. I have used them at my day job and I’m using one of their DC ssr’s on my rostock max as well.
Awesome. Thanks everyone!
@Dont_Miyashita Your 220v configuration would have half the current flow that a 110v system would use. It’s good that the general consensus is that they don’t get particularly hot, but the idea of a heat sink is to remove heat from the circuit providing the switching.
Adding a spacer may prevent an overheat from melting the acrylic and it will indeed provide for airflow across the flat heat transfer surface.
If the temps get high enough, something to draw the heat away will mean longer life for the device, even if we don’t get to enjoy plastic melting in time-lapse.
The spec sheet for the referenced SSR appears to indicate that temperature increase for the approximate 8 watt load would be less than 10°C unless I’m reading it incorrectly.
Seems like no spacer or yes spacer should work well enough.
I’m also having the acrylic panel laser cut so there will be a hole underneath the base of the SSR for airflow.
@Adam_Steinmark a hole would probably be enough. I’ve been using a cheap chinese ssr for years now, mounted on a heatsink, but it never gets warm. It’s specified for 10A, and my heater takes about half of that.
@Fred_U Correct. 8 Watts is still 8 Watts but spacers and/or a hole underneath is enough to generate an airflow.
@Eclsnowman You mean the genuine one or counterfeit? Most Fotek teardown on youtube I find is fake one.
Foteks are very commonly fraudulently relabeled too. Genuine Foteks of low amp rating are relabeled with a higher amp “rating” to sell at a higher price. UL has a page so you can identify the fraudulently labeled ones.
I’ll second the vouching for Crydom, I have a couple in one of my machines.