Replacing SSL E/G computer fans

[njm]

So the time has come for me to replace the 6 fans on another E/G computer.

For those of you who have done this before you will know that the fans are at the top of the computer with the fan frames facing upwards and the fan rotors facing downwards, drawing heat up through the chassis. Mechanically the fans are upside down, when the rotor is spinning the weight and friction wears down the bearings/washers prematurely.

In standard fans the air flows from the open end of the frame towards the back of the frame when the motor support struts are. Is it possible to get fans that flow in the opposite direction? Attached pic might explain better....

 

[sodderboy]

Yes. That's what I did. I kept the flow direction the same but had the rotor sitting rather than hanging. You will have to dome the cage screens so that they do not scrape the rotors.  Just make sure that you get high quality ball bearing fan. That used to be comair rotron but they were gone the last time I re-fanned. I got a Chinese brand because the client did not want to pay for Pabst.
You should look to get 10 years life span from a good fan.
Mike

 

[njm]

Cheers sodderboy

I've looked through the papst and comair websites, couldn't see anything that runs in the reverse direction. Will give papst a call tomorrow.

I have seen the rotors fall out of these before where the bearings have worn down. Took the lid off one computer and 3 of the rotors were just sitting on top of the card rack.

 

[sodderboy]

I would have had those fans long gone before they had a chance to drop.  When they start groaning they are gonzo.

I checked Newark here which has ties to Farnell.  They have NMB fans, which are what I used in place of the Pabst, in 230 volts which I imagine are in your rack?  Check the specs for the direction you want.  If you do the computer and one supply you get to a qty 10 discount.
Mike

 

[njm]

Farnell have some NMB fans, but all DC and standard air direction. The search term we are looking for is "air intake over struts" !

I'm going for Papst 4656N (230VAC, 19W, 160m3/h, ball bearing) RS code 272-0396, £40 each!! These things aren't cheap....
The Papst 4650N has the same specs but sleeve bearing, RS 101-0396 at £26 each

Interestingly SSL used 115V fans on 230V computers, wired them in series pairs. I'm gonna scrap that though, can't get any of these "air intake over struts" fans in 115V

Cheers for your help Mike!