Heat gun modification with SSR controller

[ec911]

Hi,

This is my first post on the forums, and I have a question for you concerning a SSR. I am modifying a heat gun to control the temperature precisely with a rex C100 controller and a SSR. The thermocouple is installed inside the nozzle just past the element. Everything is working good except when I tried to install a power diode that I salvaged from the heatgun to reduce the voltage to the element since I don't need it to work at full power.

After I installed the diode, when I turn on the heat gun and the controller, it gets up to the set value but then as soon as it reach the temp and the SSR turns the power off, it won't turn back on.  I'd like to know if it's because I have a zero-cross SSR that it doesn't work.

Thanks

[macboy]

Yes, almost certainly.

Try putting a capacitor across the diode, around 0.22 to 1 uF. This will allow a little bit of current in the reverse direction too, maybe enough to make it work. You can't use just any capacitor, it should be an X2 rated AC safety capacitor. If you have ever salvaged parts from a switching power supply (old ATX computer supply, most consumer electronics supplies) then you have definitely come across these. They are always rectangular and have "X2" among the markings.

[ec911]

Ok I will try that thanks!

Do you think a random turn-on SSR would also work without a capacitor across the diode?

[cybertronicify]

This might be a bit late, but have you tried to replace the SSR with a TRIAC?