Why do large drum fans only come in 2 or 3 speeds?

[Blue98GT]

Wondering why Direct Drive drum fans only come in 2 speeds and Belt Drive some in 2 or 3 speeds.

I'm looking for more speeds so it's not so loud in the garage but don't want to use a box fan.

This is the one I have but it's really loud on the low setting.

http://www.globalindustrial.com/p/h...y-portable-air-circulator-bf30dd-red-5500-cfm

 

[Bondo]

Ayuh,.... How much air ya tryin' to move,..??

I have a few squirrel cage fans, taken from hot air furnaces,...

Donno the Cfm's of 'em, but they move alota air,...
Originally used to blow heat through whole houses,....

Wire in the right switch, 'n ya might be able to run infinite speeds,....

 

[Radix2]

The reason is that these types of fans use PSC motors - the speed is determined by tapping into the windings at various spots. It is difficult and costly to create much more than two or three taps, plus the required switch and wiring. Many of these large fans use standardized motors and that is how they come.

 

[ewang]

You could probably retrofit a ECM motor on it and that would give you infinite variability....

But would also be expensive!

 

[LS6 Tommy]

About the only way you get quieter wihout giving up CFM is to go for a HUGE diameter blade with a steep pitch angle runing at a low RPM...

Tommy

 

[Blue98GT]

About the only way you get quieter wihout giving up CFM is to go for a HUGE diameter blade with a steep pitch angle runing at a low RPM...

Tommy

And that is exactly what I'm after. I have a 30" Direct Drive drum/barrel fan and want to slow it down. Some for the noise factor but it would be nice to have a lower flow rate when higher flow isn't necessarily needed.

 

[LS6 Tommy]

If you had a belt drive fan you could increase the driven pulley diameter or decrease the drive pulley diameter (or both) to reduce blade RPM.

Tommy

 

[csp]

The intended use of these fans is to move lots of air, so why would they incorporate a low speed? There are other types of fans for low volume.

Not saying your idea isn't valid, it just doesn't follow what these fans are made for.

 

[Farmall450]

The intended use of these fans is to move lots of air, so why would they incorporate a low speed? There are other types of fans for low volume.

Not saying your idea isn't valid, it just doesn't follow what these fans are made for.

Exactly. Got my dad the 36" or 38" Maxxair for his birthday and its two speeds is more than sufficient. Wouldn't buy that big of fan to do what a box fan can

 

[Muzzy]

Have you tried a dimmer switch?