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gmat · 12-30-2005, 10:04 AM

yes this is not a linear relation

Here is an example of flow vs pressure curve - for instance the graph for the papst 4212 NGML (38 dBA @12V)

and the 4212 L (28dBA @12V)

And more interesting they have "variofans" so they publish speed vs pressure/flow curves:

this is for a 80x25 variofan, controlled by a thermistor, so it's temperature which varies, but basically the thermistor (with its control circuitry) varies the voltage between 8V and 12V. The only problem is the thermistor response to temperature linear ? Like billbartuska said we are a special population - when engineering products for the industry the provided graphs are enough, you just want to know temperature vs flow, the actual voltage / rpm is not relevant.

12-30-2005, 10:04 AM	#40
gmat Thermophile Join Date: Mar 2001 Location: France Posts: 1,221	Re: How to choose the optimal 120mm fan? yes this is not a linear relation Here is an example of flow vs pressure curve - for instance the graph for the papst 4212 NGML (38 dBA @12V) and the 4212 L (28dBA @12V) And more interesting they have "variofans" so they publish speed vs pressure/flow curves: this is for a 80x25 variofan, controlled by a thermistor, so it's temperature which varies, but basically the thermistor (with its control circuitry) varies the voltage between 8V and 12V. The only problem is the thermistor response to temperature linear ? Like billbartuska said we are a special population - when engineering products for the industry the provided graphs are enough, you just want to know temperature vs flow, the actual voltage / rpm is not relevant.