SSR relay problem solution

[mdkmdk]

Hello everyone,

I have a goldsmith oven to which I had to change an SSR relay because when it reached 475 degrees centigrade the temperature increase stopped. Since the oven must reach 800 degrees in about two hours, I have to solve the problem.

I changed all the main components to the oven: thermoregulator, thermocouple, resistance. The problem of increasing the temperature was present even before changing all these components.

I ordered an SSR relay of the same brand and model as the one mounted on the oven: Crydom D2425.

Since it was panel mounted I proceeded to modify the panel to put a heatsink in it.

Between the heatsink and the relay I put some Thermalright TFX thermal paste which has a high thermal conductivity power and is also used in computers and can withstand up to 300 degrees.

After having reassembled everything I turned on the oven, this time it reached 100 degrees centigrade after 10-15 minutes the increase in temperature stopped.

I wonder where he went wrong about the SSR relay changing as I think I've done everything possible. Could anyone help me? Thank you in advance for your reply.

I attach some photos to the message.

 

[marconi]

To what is the round orange panel lamp on the left of the controller connected?

what is the purpose of the round silver knob to the left of the round orange panel lamp? Is it a timer?

Is the clicking sound from the controller?

 

[mdkmdk]

To what is the round orange panel lamp on the left of the controller connected?

what is the purpose of the round silver knob to the left of the round orange panel lamp? Is it a timer?

Is the clicking sound from the controller?

The round red light that flashes is that of the heating, when it is on the heating is on, when it goes off it is because the controller does not send current to the SSR relay and consequently the heating light does not turn on either. The square light you see instead is a two-pole switch. The round knob is a switch-off timer which, if set, switches off the heating for a set amount of time. The noise you hear I believe is the controller, the light or the SSR relay I don't think they can make noise.

I read the previous message, if I put the AT on and set the temperature to 800 degrees, it could be that even after several hours the AT never turns off.

 

[marconi]

Yes. It could take several or many hours for the AT to tune successfully. But, even after a very long period, the AT as designed and implemented inside the controller might be unable to home in to the best values using its trial and error approach to tuning. In which case we leave AT off and use the figures I said to use and adjust them over the life of the oven until we are satisfied with the performance. Auto tuning algorithms are not perfect in all applications.

I must repeat that you have to allow AT at least 3 hours from when the oven first reaches 800C to attempt tuning and ideally longer say 6 hours. At the moment AT may not complete because you turn the oven off too early.

 

[mdkmdk]

Yes. It could take several or many hours for the AT to tune successfully. But, even after a very long period, the AT as designed and implemented inside the controller might be unable to home in to the best values using its trial and error approach to tuning. In which case we leave AT off and use the figures I said to use and adjust them over the life of the oven until we are satisfied with the performance. Auto tuning algorithms are not perfect in all applications.

I must repeat that you have to allow AT at least 3 hours from when the oven first reaches 800C to attempt tuning and ideally longer say 6 hours. At the moment AT may not complete because you turn the oven off too early.

I did the test by leaving the oven on and waiting for more than 6 hours after reaching 800 degrees. The lights of the AT were still flashing, the AT unfortunately did not work.

 

[marconi]

I conclude that AT will not work for your oven. We have tried to use it many times without success. Turn it off and just use the controller with a setting of 800C. Please tell me how the oven performs and allow an hour after reaching 800C.

AT makes some assumptions about the system (your oven) the controller drives. It may well be your oven does not satisfy one or a few of these assumptions which means trial and error does not home in on better and better values for P and I and the other variables.

 

[mdkmdk]

I conclude that AT will not work for your oven. We have tried to use it many times without success. Turn it off and just use the controller with a setting of 800C. Please tell me how the oven performs and allow an hour after reaching 800C.

AT makes some assumptions about the system (your oven) the controller drives. It may well be your oven does not satisfy one or a few of these assumptions which means trial and error does not home in on better and better values for P and I and the other variables.

Good evening marconi, for about 10 days I'll be away, as soon as I'm back I'll do the tests you requested and I'll put the results on the forum, as always thanks for your help

 

[Darkwood]

Any feedback on this,did we resolve the situation?

 

[mdkmdk]

I conclude that AT will not work for your oven. We have tried to use it many times without success. Turn it off and just use the controller with a setting of 800C. Please tell me how the oven performs and allow an hour after reaching 800C.

AT makes some assumptions about the system (your oven) the controller drives. It may well be your oven does not satisfy one or a few of these assumptions which means trial and error does not home in on better and better values for P and I and the other variables.

Any feedback on this,did we resolve the situation?

Sorry for the absence.

I did the test # 125:

I set the oven at 800 degrees with the AT off and the variables P and I respectively with the values 15 and 160.

Summarizing the values currently present in the oven are the following:

At = No
AL1 = 10
SC = 0
P = 15
I = 160
d = 0
t = 2
rSt = -005
LCy = 0

Test report:

It reached 790 degrees in 2 hours and 26 minutes.

The heating of the oven since I turned it on has always remained active up to 780 degrees, from that temperature onwards it began to switch off and on again quickly, as visible by the flashing red light in the videos I attached in the previous messages.

At 793 degrees the heating started to be on again continuously.

The temperature dropped to 790 degrees despite the heating light was steady.

The temperature rose to 793 degrees and started flashing again.

While the red light was flashing the oven reached the temperature of 796 degrees.

It subsequently started to go down.

When it reached again 793 degrees the red light became steady again.

It began to descend to 790 degrees and then to rise again.

At 793 degrees the red light started flashing again.

The cycle repeated itself continuously without ever reaching 800 degrees.

 

[Darkwood]

Do you have any connection points in the wiring, do they follow through with the elemental materials of the cable cores? There are so many things you may need to account for, even position of the thermocouple if so you may need to program an offset in to get you to that temp' you seek since now you are in the ball park, of course if you have a wide margin of error it may not matter.

 

[DPG]

I'm no expert in these things, but is 793 not close enough to 800? You seem to be aiming for a very high accuracy.

 

[Avo Mk8]

Or how about changing the set point to 807 degrees, and seeing if the resulting temperature is around 800!

 

[Darkwood]

Trust me certain melt points and cool down times have to be so precise, carbon fibre is a classic if used on aviation, it requires a full temp chart approval

 

[ankyzop]

set your multimeter to DC volts range so you can pick up 3-32 volts. Connect Positive lead to 3 and common or negative lead to 4. MAKE sure you are reading volts not current....

 

[DPG]

set your multimeter to DC volts range so you can pick up 3-32 volts. Connect Positive lead to 3 and common or negative lead to 4. MAKE sure you are reading volts not current....

We covered that back in the early oart of this thread.

 

[ankyzop]

yea, thanks for your reply.
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