Re: DC fans versus AC fans (System Saver IIGS)

[Wayne Stewart <waynes@intergate.bc.ca>]

I've always thought some brands were just quiter designs but
even some units among the same make & model can be a lot
quieter than others. Newer designs seem a lot lighter & quieter.

I'd assume the 120v AC fan is a lot cheaper than a 12V DC
fan along with all the parts necessary to supply 12volt DC
currant, also adding steps to the assembly process increases
costs too.

Supertimer wrote:

> Picked up a System Saver for my backup IIGS and the
> first thing I noticed was how loud the fan was.  When
> I opened the case, I found a huge AC fan.  Are AC fans
> just more noisy than DC fans?
>
> Since the tower unit of my flagship IIGS has two fans, I
> took one and installed in in the System Saver in place
> of the AC fan.  For 12V DC power, I found the power
> supply board from an old junk hard disk case I had and
> mounted it inside the System Saver.  From the System
> Saver's 120V AC leads for the AC fan, I connected the
> power leads to the power supply board from the junk HD
> case.  Then from the fan leads of that power supply board
> (12V DC), I connected the leads to the 12V DC fan from
> the tower case.
>
> The DC fan seems to move the same volume of air but is
> much quieter.  Why is that?  Are DC fans inherently
> quieter?  The AC fan seems to have a huge core and
> stubby fan blades.  The DC fan has wide fan blades and
> a slender core.  Could this be the cause?
>
> With the AC fan gone, the System Saver is much lighter
> too.  Why didn't Kensington use DC fans in the first place?