PSU thermal protection

Joined
Jul 26, 2020
Messages
14
KSD301 N/C Thermostat Assortment Kit Temperature Switch, Bimetal Disc A323

That is a part number for an automatically self resetting thermal switch, such that a coffee machine uses. Closed normally and opens when the temperature gets to 210 degrees F. I have reason to install them on my heat sinks on my PSU, so that I do not
have another one burn out with a puff of smoke. The solid state semi conductors get extremely hot before burning out. I see no
fuse or thermal fuse.

Because my PSU's are expensive, I am going to fasten a N/C Thermostat to the aluminum heat sink. Then wire 110 line voltage from the hot black wire through it, back to the circuit board.

This take daring, since no one else has ever done this. A Computer is NOT Underwriters Laboratory Listed or Approved. The
metal case should be good enough, but the manufacturers did not pay U.L. to list their product after having them test it. With this
retro fit, it would be more U.L. approved, for insurance reasons.

Any thoughts?
 

kirbyrj

Fully [H]
Joined
Feb 1, 2005
Messages
26,538
KSD301 N/C Thermostat Assortment Kit Temperature Switch, Bimetal Disc A323

That is a part number for an automatically self resetting thermal switch, such that a coffee machine uses. Closed normally and opens when the temperature gets to 210 degrees F. I have reason to install them on my heat sinks on my PSU, so that I do not
have another one burn out with a puff of smoke. The solid state semi conductors get extremely hot before burning out. I see no
fuse or thermal fuse.

Because my PSU's are expensive, I am going to fasten a N/C Thermostat to the aluminum heat sink. Then wire 110 line voltage from the hot black wire through it, back to the circuit board.

This take daring, since no one else has ever done this. A Computer is NOT Underwriters Laboratory Listed or Approved. The
metal case should be good enough, but the manufacturers did not pay U.L. to list their product after having them test it. With this
retro fit, it would be more U.L. approved, for insurance reasons.

Any thoughts?
If I was an insurance company, and your place burnt down, and I didn't want to pay a claim...

I'd argue that you caused the fire by changing the specs of the PSU and rewiring it yourself. If you're going to do it for your own peace of mind, so be it. But for insurance purposes? I think it would actually hurt you rather than help you.
 

ryan_975

[H]F Junkie
Joined
Feb 6, 2006
Messages
14,853
A lot of time those heat sinks are connected directly to the electrodes of what they’re cooling and can be energized. Even if you didn’t directly short something out, you could be coupling your mains to the high voltage high frequency power running in the PSU.
 

vegeta535

Supreme [H]ardness
Joined
Jul 19, 2013
Messages
4,570
Well for one you void the warranty of your expensive PSU and any possible parts replacement if the PSU took out other components. There is no reason for you to be doing this. If you PSU is really running that hot you have other issues you need to look into.
 
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drutman

Limp Gawd
Joined
Jan 4, 2016
Messages
215
All PSUs have thermal and short protection on them, especially high quality units. I would not mess with the thermostats coming from a person with MV industrial switchgear QC experience.
I had a relative who rewired his house and it burned, guess what insurance denied his claim.
If you think it is running hot improve the airflow around and inside the PC.
 
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Azrak

Gawd
Joined
Oct 4, 2015
Messages
958
Why is your PSU getting to 210 F (99C) in the first place? The PSU fan should be keeping it WELL under that (I mean like 60C worst case). If not, you have other problems that need to be solved and thermal cutouts are not the answer. Fix the original problem, don't add patchwork by messing around inside a PSU.
 
Joined
Jul 26, 2020
Messages
14
Why is your PSU getting to 210 F (99C) in the first place? The PSU fan should be keeping it WELL under that (I mean like 60C worst case). If not, you have other problems that need to be solved and thermal cutouts are not the answer. Fix the original problem, don't add patchwork by messing around inside a PSU.
A $29.00 PSU that was supposed to be rated at 750 Watts. The irst thing I noticed was when by accident I shorted it, and it gave
a spark. Too healthy a spark, for a switching power supply. They are designed to PULL DOWN the voltage to zero, and not cause damage.
No reason while I was working on my computer for a problem. When I saw the heat sink melted that would mean 1200 degrees F. was arcing. The semiconductor did not clear to open but lit an arc. A tin thermal link would clear at 400 degrees and lead at 600.
The question of stopping additional damage while any component has to burn out. If one diode in a rectifier burns out and a fuse has to blow or a component has to fail, due to AC current going through the circuit.

A bench technician should test the PSU's to see if they pull down the voltage to zero when shorted, and do not have to have
an electrical arc. Then put his certification on it, to say it has been approved.
🤓
 

vegeta535

Supreme [H]ardness
Joined
Jul 19, 2013
Messages
4,570
A $29.00 PSU that was supposed to be rated at 750 Watts. The irst thing I noticed was when by accident I shorted it, and it gave
a spark. Too healthy a spark, for a switching power supply. They are designed to PULL DOWN the voltage to zero, and not cause damage.
No reason while I was working on my computer for a problem. When I saw the heat sink melted that would mean 1200 degrees F. was arcing. The semiconductor did not clear to open but lit an arc. A tin thermal link would clear at 400 degrees and lead at 600.
The question of stopping additional damage while any component has to burn out. If one diode in a rectifier burns out and a fuse has to blow or a component has to fail, due to AC current going through the circuit.

A bench technician should test the PSU's to see if they pull down the voltage to zero when shorted, and do not have to have
an electrical arc. Then put his certification on it, to say it has been approved.
🤓
A $29 750 watt power supply is not a expensive PSU. Sounds like you had a defective unit. What is the make and model of the PSU?
 
Joined
Jul 26, 2020
Messages
14
If I was an insurance company, and your place burnt down, and I didn't want to pay a claim...

I'd argue that you caused the fire by changing the specs of the PSU and rewiring it yourself. If you're going to do it for your own peace of mind, so be it. But for insurance purposes? I think it would actually hurt you rather than help you.
How about, some LED's that give a computer SYSOP, and idea of how the computer is feeling via, colored LED's. 5 volts for
Hard disks, and 12 volts for the motherboard, and what ever else. When a voltage is pulled down, the LED goes from green to amber to red. We can see by the blinking lights that a component such as a hard disk is starting to get stuck and momentarily pull down the voltage. Most people only want to see this and not any liquid crystal display, with exact voltages.

I have an Antec EA-750 that appears to have a small attached circuit board with 4 resistors that burnt off the copper foil, and would no longer function to 100 %. 2960319603. Maybe I wrecked the rice. I voided the manufacturers certification, when I removed a sticker on a screw head, to even see this condition. The semiconductor on the heat sink looks pretty hefty. Heavy duty PSU.
 
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