Turned the oven on for 1st time - Fireworks!

[BottleFed70]

At 1st everything looked great. The oven came up to around 200*F then suddenly there was fireworks in the electrical box.

For some reason my 40A SSR melted. I'm running 2 x 3000W elements which works out to about 26A. I even had the SSR bolted to the electrical box so that there was some heatsinking.

I bypassed the SSR and was able to get the oven up to 700*F without a problem.

According to the SSR it's rated at 40A and up to 380VAC. Any ideas as to what went wrong?

[CarWiz]

Got a schematic? What controller?
How did you "bypass" the SSR?

It's sounding a lot like you were trying to drive the SSR from a controller relay.

[BottleFed70]

It's a coldfusion FX PID controller from ebay. This controller has outputs for both relay/contactor as well as SSR. I was using the SSR outputs.

To bypass the SSR I just shorted the contacts at the SSR so that as soon as I plugged in the oven, the elements would come on and stay on.

Here's a link to ebay auction for the controller:
http://cgi.ebay.com/ws/eBayISAPI.dll...5398&rd=1&rd=1

Here's the like to ebay auction for SSR (same seller) although the SSR I got looks a little different:
http://cgi.ebay.com/ws/eBayISAPI.dll...5412&rd=1&rd=1

Attached is a quick sketch of my schematic.

[CarWiz]

I couldn't find any specs on the "ASR-240D" shown. If yours is different, what model is it? There's lots of different SSRs. The one you used for reference is some Ching-Chang stuff with who knows what specs. It could be 40A at 25v and 5A at 240v. Write the seller and tell him it went up in smoke and you question the 40A rating.

I'm using OPTO-22's model 240D45. The heat sink on the bottom is 1/4" thick and as large as the SSR. The one in your example looks like the heat sink is tiny.

[didde]

I changed a SSR out awile back and the heatsink was 2 inches thick with fins it was a 40 amp on a Dispatch oven.

[BottleFed70]

Thanks guys,

After some additional research, the only thing I can come up with is that there wasn't enough heatsink.

Just having it bolted to the side of the electrical box probably wasn't enough. I'm going to try again with a new (and better quality) SSR along with a good sized heatsink.

[rowdenboyz]

I bought the same controller and SSR. The controller I received has a different part number than what was pictured on ebay. The SSR was also different. I ordered a 60A and received a 75A. I guess my gain huh. I don't know whether to believe the specs on the site if my controller is different? The SSR voltage output on my controller says 8V open? WHat does that mean? Here is the controller ebay# 190124616324


I Need HELP!!! Too!!!

[donafams]

why not just use a contactor instead of a SSR? it works great for me

[BottleFed70]

Using a PID controller with a SSR gives much better temp control/stability.

The controller "pulses" the SSR as the temp gets close in order keep the temp as steady as possible. You could do the same with a contactor but you'd wear it out pretty fast.

[rowdenboyz]

I just completed my oven this past weekend and the exact same thing happened to my SSR. The oven started heating up and got to about 200 degrees and POP! The SSR melted and popped in two! Smelt real nice too! I have 4 2500 watt elements and the SSR is rated at 75A so I know the sizing is ok. It doesn't have a heatsink, but I mounted it 1.5" off of the panel and mounted a cooling fan behind the box to cool the electronics. My question is: Did the new SSR take care of your problem? I'm not looking forward to trying this again. Kind of hard to believe the heatsink would be the problem since it was only on about 10 minutes. Any suggestions?