Killing SSR (relays) - Need to understand
- Thread starter jwest7788
- Start date
27.6a peak.
26.0a after 1 hour heating. (Was slowly dropping as the coils got hotter, would have kept heating for another hour or so.)
Confirmed at 236.2V (just to be sure. Haha)
All measured leading into the system as noted.
That help at all? (30A breaker feels slightly warm to the touch... )
JW
26.0a after 1 hour heating. (Was slowly dropping as the coils got hotter, would have kept heating for another hour or so.)
Confirmed at 236.2V (just to be sure. Haha)
All measured leading into the system as noted.
That help at all? (30A breaker feels slightly warm to the touch... )
JW
The measurements look well inside the capabilities of the SSR.
Are the screws of the breaker tight well?
About the failure of the SSR:
How long does it take before it fails?
Do you have a way to measure it's case temperature?
Please post the data sheet of the SSR.
Are the screws of the breaker tight well?
About the failure of the SSR:
How long does it take before it fails?
Do you have a way to measure it's case temperature?
Please post the data sheet of the SSR.
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It usually runs for a little over an hour before failure.
I'll figure out something to measure the ssr, as well as the case that it's held in. will report back.
I don't have a data sheet handy, after some more research I fear it's likely a knock off ssr. (Bought it online relatively inexpensively)
I will double check the breaker screws too. It's a 30A breaker with a ~26.5A load, is it normal for them to heat up to the touch?
JW
I'll figure out something to measure the ssr, as well as the case that it's held in. will report back.
I don't have a data sheet handy, after some more research I fear it's likely a knock off ssr. (Bought it online relatively inexpensively)
I will double check the breaker screws too. It's a 30A breaker with a ~26.5A load, is it normal for them to heat up to the touch?
JW
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Okay here's an odd update.
Working under the assumption that heat was the issue, I cut a hole into the (vented) enclosure, and added a PC fan to blow extra cool air across the SSr heat sink.
Turned her on and it worked perfectly up to temp, (overshot a little) and while the SSR was open (not passing current) I head the tell tale "ZZZZT POP"and looked over just in time to see the SSR letting it's smoke out!
Total failure (obviously) of the SSR.
Bought an infrared thermometer and checked, the SSR was 80C even with the fan, heat sink (thermal paste) etc.
What the heck am I doing wrong!
Working under the assumption that heat was the issue, I cut a hole into the (vented) enclosure, and added a PC fan to blow extra cool air across the SSr heat sink.
Turned her on and it worked perfectly up to temp, (overshot a little) and while the SSR was open (not passing current) I head the tell tale "ZZZZT POP"and looked over just in time to see the SSR letting it's smoke out!
Total failure (obviously) of the SSR.
Bought an infrared thermometer and checked, the SSR was 80C even with the fan, heat sink (thermal paste) etc.
What the heck am I doing wrong!
That heat is way too high!
Please measure the driving signal to the SSR
And a good photo of the physical construction of your circuit .
That doesn't allow much margin. However, if the SSR is popping when there's no load current the problem is presumably with the driver.
Are you claiming the SSR is burning up when it has cycled off? If so, I think your circuit is the responsible party.
Can you show us the exact complete circuit. The previous circuit you published had to be wrong since it connected the AC line voltage to one of the control pins on the SSR (or maybe this is the actual circuit and that is why it is failing)
Bob
Can you show us the exact complete circuit. The previous circuit you published had to be wrong since it connected the AC line voltage to one of the control pins on the SSR (or maybe this is the actual circuit and that is why it is failing)
Bob
Man, I'm really realizing I need to study electronics / electricity much more, as I'm really continueing to struggle.
Here's a pic, but before you examine it, some notes:
This thing is only run with me present, as I'm afraid of a fire risk, fire extinguisher present.
Theres lots of wiring and mechanics here ,nothing is actually wired to my circuit except for:
SSR, PID, thermocouple, heating coils. Everything else is just there as a remnant to when this thing was a pottery kiln.
Most recently, after getting rid of every connection that wasn't absolutely needed, the SSR failed, and the PID popped. Damn.
I'm thinking, instead of repairing this circuit, can anyone provide a recommended solution to allow these two heating coils to run with a digital temperature control? Like, obviously I'm missing something, and it's getting costly replacing these components...
JW
Here's a pic, but before you examine it, some notes:
This thing is only run with me present, as I'm afraid of a fire risk, fire extinguisher present.
Theres lots of wiring and mechanics here ,nothing is actually wired to my circuit except for:
SSR, PID, thermocouple, heating coils. Everything else is just there as a remnant to when this thing was a pottery kiln.
Most recently, after getting rid of every connection that wasn't absolutely needed, the SSR failed, and the PID popped. Damn.
I'm thinking, instead of repairing this circuit, can anyone provide a recommended solution to allow these two heating coils to run with a digital temperature control? Like, obviously I'm missing something, and it's getting costly replacing these components...
JW
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- Dec 18, 2013
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One problem I can clearly see is the SSR gets too hot.
80 degrees Celsius is just at the top recommended working temp. range.
Fotek SSR-40DA datasheet
That is not good!
Are you using thermal grease?
Are the screws tight enough?
Is the fan working at all times (including turning off the SSR)?
Look at the photo.
80 degrees Celsius is just at the top recommended working temp. range.
Fotek SSR-40DA datasheet
That is not good!
Are you using thermal grease?
Are the screws tight enough?
Is the fan working at all times (including turning off the SSR)?
Look at the photo.
- Joined
- Dec 18, 2013
- Messages
- 5,178
This may also be of interest, might be worth taking a duff one apart? http://www.instructables.com/id/The-inner-workings-of-Counterfeit-FOTEK-SSRs/
Adam
Adam
