Author Topic: SMPS Thermal sensor position  (Read 875 times)

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Offline innkeeperTopic starter

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SMPS Thermal sensor position
« on: May 25, 2020, 08:51:50 pm »
I have a Meanwell style Chinese power supply that has a thermal switch to control the fan.
Thing is, the thermal switch is just tucked into the output inductor.
Meanwell themselves seem to have their sensor on the pcb and using some kind of solid sliastic type material to 'glue' it to the inductor.  (not a thermal epoxy, it is just that hard type silastic compound)
This particular supply seems well put together, and not your typical cheap Chinese supply, even using quality caps... so this was the one thing that seemed, odd.
Is this the right place to put such a thermal switch. or would it be better mounted to the case?
Is this typical? I am used to seeing thermal switches or sensors on the heat sink. though the heat sink here would be the case itself.
996951-0996953-1996955-2

« Last Edit: May 25, 2020, 09:38:43 pm by innkeeper »
Hobbyist and a retired engineer and possibly a test equipment addict, though, searching for the equipment to test for that.
 

Offline uer166

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Re: SMPS Thermal sensor position
« Reply #1 on: May 25, 2020, 10:42:19 pm »
If the inductor happens to be the hottest part, then surely this is the best possible location of the thermistor? If the FETs are the hottest, then best place would be on-PCB for SMD FETs or heatsink if they're TO-220. This seems like a great quality supply, at least visually, and the fact that they spent extra effort to thermally protect the inductor is great.
 
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Offline TimNJ

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Re: SMPS Thermal sensor position
« Reply #2 on: May 26, 2020, 04:04:44 pm »
Probably don't need to add anything more to uer166's response, but in general, the magnetic components are often the most stressed components on a power supply. Of course, it really depends. For some power supplies with very limited space, there is no option but to use a smaller core size and let the inductors/transformer run hot. In this case, space doesn't seem to be so much of an issue, but still may be the case.
 


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