Controlling PSU fan with DigitalDoc 5

Steerpike · Post by **Steerpike** » Mon Aug 12, 2002 2:32 pm

I've just bought a Zalman quiet PSU, but I'm hesitant to mod it yet; so I took my old PSU as a test, and made the following changes.
 
 Replaced the stock fan with a panaflo. Ran the wire from the panaflo out of the case to a Zalman fanmate speed controller (voltage reducer)and then to my DigitalDoc 5 temp monitor/fan controller. Hot-glued a thermistor to the heatsink of the PSU, and ran it to the DigitalDoc5. Ran it for several hours with fan on full, monitoring temp of the PSU - which stabilized just below 40C (ambient=24C).
 
 Next, I plan to crank the fan down to a very low speed and monitor the PSU temp. Ultimately, I'd like to set a threshhold in the digitaldoc, and have the fan come on only when necessary. Is this a big risk? I have a case fan too, so there's still airflow in the case.
 
 Since the temp I'm monitoring on the PSU is somewhat 'arbitrary' (I just glued the sensor where it was convenient; I'm sure if I pick different locations, it would give different readings), I can't read too much into the value (39C). But assuming that value with fan on full, what would be a good 'limit' to watch for with the fan off or on very low speed?
 
 
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Post by **MikeC** » Mon Aug 12, 2002 2:32 pm

Most PSUs are specified for operation at 0 - 50C. Arbitrarily, if the sensor location is close to the hottest spot in the PSU, 50C is *probably* a good safe maximum.
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