What size cooling fan?

[chromian]

I want to replace a cooling fan that is making a racket.
Can I measure the size accurately without taking it out and closing down the
computer? How are fans measured? Do I measure the screw head separation,
horizontal or diagonally?
Presumably the external dimensions are unimportant, it's the mounting screws
that need to be right.
Sorry for the dumb question, but I don't want to order the wrong thing.

Thanks

Ian

 

[w_tom]

Sizing is industry standard. For example, 80 mm fans will
have screw holes in same place. Go to professional suppliers
catalogs for further details www.digikey.com,
www.alliedelec.com, www.mouser.com, www.newark.com . Or
visit the technical websites for those fan manufacturers.
Notice a quieter fan of same size moves less CFM. You are
concerned both with dB and CFM parameters.

 

[kony]

I want to replace a cooling fan that is making a racket.
Can I measure the size accurately without taking it out and closing down the
computer? How are fans measured? Do I measure the screw head separation,
horizontal or diagonally?
Presumably the external dimensions are unimportant, it's the mounting screws
that need to be right.
Sorry for the dumb question, but I don't want to order the wrong thing.

Thanks

Ian

They're measured by width (or length, they're square) and thickness,
not screw hole spacing, which is standard for a given width.

Typical size depends on the application. Video cards or really old
486 or Pentium CPUs might use 40-60mm x 10-15 mm thick fans, and newer
CPUs usually 40-60mm, even newer CPUs 60-80mm, and cases & power
supplies generally use 80mm, though some are 60-92mm, x 25mm thick.
Rarely a case or power supply will use a thinner, 10-20mm thick
instead of 25mm.

If it's on a video card also consider the voltage- some video cards
use 5V fans, even though 12V are more common, though most other
applications are likely 12V.

So for a concise list, it's probably one of these:

40, 50, 60, 70, 80, or 92 mm wide
10, 15, 20, or 25 mm thick.

12V... 5V not so common but it should be listed on the label or check
the connector, what it plugs into

Also consider current draw, which might also be on the label... choose
similar current for similar airflow, or lower for less airflow &
noise, if the application will tolerate the lower airflow. Name-brand
fans are worth the extra expense, last longer and might be quieter.

If your current fan is a sleeve-bearing model you might be able to
quiet it down, keep it working temporarily by adding a drop of oil to
the bearing (peel back the sticker).

 

[chromian]

Many thanks. That's a great help. I have 4 fans in the case, 2 on the PSU, 1
on the video and one on the CPU. Altogether they make a racket and it's
getting worse. Woodsmoke I think.
I'll do them one at a time, but the worst one is on the input of the 500W
power supply. It moans.

Thanks again,

Ian

 

[ric]

I want to replace a cooling fan that is making a racket.
Can I measure the size accurately without taking it out and closing down the
computer? How are fans measured? Do I measure the screw head separation,
horizontal or diagonally?
Presumably the external dimensions are unimportant, it's the mounting screws
that need to be right.
Sorry for the dumb question, but I don't want to order the wrong thing.

For dimension drawings, see:

http://www.pcpowercooling.com/products/alarmandaccesories/silencerfan/index_diagram.htm
http://www.pcpowercooling.com/products/alarmandaccesories/silencerfan/index_diagram92mm.htm