Is the rpm of a fan directily proportional to voltage?

[Fullmetal Chocobo]

Given that the fan has enough voltage to start, are voltage and rpm (and thus cfm) directly proportional? So a Sanyo Denki fan that does 102.5 cfm @ 12 volts, would it do ~59 cfm @ 7 volts?

Just wondering. I'm researching fans to get for the next case...

 

[JAG87]

i dont think thats exactly how it works because a fan does not push 8.54 cfm at 1V. it doesnt move at all at 1V. so you have to find out how many CFM it moves at 5V, and then you can make a linear scale up to 12.

 

[Ayah]

Originally posted by: JAG87
i dont think thats exactly how it works because a fan does not push 8.54 cfm at 1V. it doesnt move at all at 1V. so you have to find out how many CFM it moves at 5V, and then you can make a linear scale up to 12.

Some fans don't even spin at 5v.

 

[Fullmetal Chocobo]

Originally posted by: Ayah

Originally posted by: JAG87
i dont think thats exactly how it works because a fan does not push 8.54 cfm at 1V. it doesnt move at all at 1V. so you have to find out how many CFM it moves at 5V, and then you can make a linear scale up to 12.

Some fans don't even spin at 5v.

Hence the "Given that the fan has enough voltage to start"...

 

[Ayah]

Originally posted by: Fullmetal Chocobo

Originally posted by: Ayah

Originally posted by: JAG87
i dont think thats exactly how it works because a fan does not push 8.54 cfm at 1V. it doesnt move at all at 1V. so you have to find out how many CFM it moves at 5V, and then you can make a linear scale up to 12.

Some fans don't even spin at 5v.

Hence the "Given that the fan has enough voltage to start"...

Usually between their starting voltage and their maximum voltage, it's a linear scale.

 

[Navid]

http://www.maxim-ic.com/appnotes.cfm/appnote_number/809/

 

[GalvanizedYankee]

I KNOW the SD you speak of It does start/run at 4.7V. At 5V it pushes close to 50cfm
in my crude testing.

I do believe that at about 10V the linear increase will start falling off a bit.

If you need some 120x38, quiet fans at 53cfm, look at the Arctic ceramics at Provantage
for < $5.


...Galvanized