Looking for cost effective fans 92mm x 6

[NiHaoMike]

Sine wave ("pure sine") and square wave/modified sine are very general concepts in converting DC to AC. You can either switch it completely on/off and wind up with square waves or modified sine or you can use PWM in order to synthesize a sine wave. (That is not to be confused with the "PWM" variable speed signal, though most variable speed fans are sine wave drive.) The latter costs more but runs smoother. What spotlights the higher end Deltas is DSP based sine wave generation, which the cheap Deltas mentioned don't have.

 

[ATMINSIDE]

Sine wave ("pure sine") and square wave/modified sine are very general concepts in converting DC to AC. You can either switch it completely on/off and wind up with square waves or modified sine or you can use PWM in order to synthesize a sine wave. (That is not to be confused with the "PWM" variable speed signal, though most variable speed fans are sine wave drive.) The latter costs more but runs smoother. What spotlights the higher end Deltas is DSP based sine wave generation, which the cheap Deltas mentioned don't have.

As I mentioned before, I'll be interested in listening when you show some products and technical data LINKS that actually exhibit this technology.

 

[ehume]

Sine wave ("pure sine") and square wave/modified sine are very general concepts in converting DC to AC. You can either switch it completely on/off and wind up with square waves or modified sine or you can use PWM in order to synthesize a sine wave. (That is not to be confused with the "PWM" variable speed signal, though most variable speed fans are sine wave drive.) The latter costs more but runs smoother. What spotlights the higher end Deltas is DSP based sine wave generation, which the cheap Deltas mentioned don't have.

As I mentioned before, I'll be interested in listening when you show some products and technical data LINKS that actually exhibit this technology.

As ATMINSIDE says, it would be helpful to see a list of square wave vs sine wave fans. Perhaps a link to where there is such a listing. Or perhaps a way to break the code -- like AFB vs BFB in the model number, or something like that.

And do other manufacturers produce sine wave fans? Square wave fans? This kind of info would be useful for all of us to have.

 

[NiHaoMike]

Nidec also makes sine wave fans with DSP drive. Sanyo also has sine wave drive, but they use analog circuits to do it instead. End result is similar and the latest ones even have phase advance so they perform just as well as Deltas and Nidecs with digital control.

Apart from that, almost all variable speed ("PWM") fans are sine wave drive since the circuit to do variable speed is almost all of what is needed to do sine wave drive. Single speed fans are almost all square wave/modified sine, except higher powered fans (more than 0.8A or so) where vibration would be a major problem and fans designed specifically for ultra low noise like Noctua (which they call "smooth commutation drive").

I'm not aware of how to decode the part numbers. I know the Deltas listed are square wave since I have some, salvaged from an old HP workstation. That's a moot point for most of us since variable speed is needed to take the most advantage of sine wave drive.