Question Replacing Tripp Lite SMART1000RM1U Cooling Fan

[weeklyCoupons]

I have a SMART1000RM1U and am wanting to swap out the stock fan. The stock fan is an Adda AD0424MS-C50 which is rated at DC24v 1.68W 0.07A.

The fan is loud as hell. I assumed that based on the rating of the fan that the voltage supplied to the fan was 24v.

I want to replace it with a Noctua NF-A4x20 FLX which is rated for DC12v 0.6W 0.05A. So, I removed the stock fan and began.

Assuming a 24v supply voltage, I added a 240ohm 1W resistor in series with the red lead of the Noctua fan.

I re-connected the battery and plugged the UPS in and noted strange behavior. The Noctua fan would run for a few seconds and then stop for a few seconds. This was while the UPS was on utility power, batteries were charging and not any under load.

So, it seemed there was not enough voltage to power the Noctua with the resistor.

I removed the fan and resistor and set up everything to test true output voltage of the fan leads with the multimeter.

After measuring, the voltage supplied to the fan leads from the circuit board is 13.8v max.

So it seems Tripp Lite a) over spec'd the stock fan for whatever reason or b) the UPS supplies more than 13.8v to the stock fan at certain, undefined points so that the RPM of the fan increases, etc.

After reading around the Internet, however, it appears Tripp Lite commonly installs over spec'd fans that operate at a consistent speed (i.e., constant voltage to the fan itself).

Any thoughts?

 

[Aeacus]

Any thoughts?

1. You have voided your UPS warranty.
2. It's rack mount UPS, in a server rack. I fail to understand why it's operating noise is an issue for you.
3. To be safe, install a fan that can operate up to 24V, while also capable of operating at 12V. The consumer grade Noctua fan, most likely would be blown, once the voltage increases. So, better look towards Delta industrial fans.

There are plethora of Delta fans to choose from, that operate up to 24V and are 40mm in size,
link: https://www.delta-fan.com/catalogse...1&voltage_rated=5700&size_dimension=5648&sku=

 

[bill001g]

Are you sure that the voltage does not change when the UPS is on battery or maybe based on temp. I know the fans in my UPS are running but you can't hear them but when it switches to battery under load the fans ramp the speed up. It is very common to change the speed of a fan with a voltage change.

If you beleive the specs on the fan you posted it is only 27.5db which is very low.

 

[Aeacus]

If you beleive the specs on the fan you posted it is only 27.5db which is very low.

UPS specs say it's noise output to be 45 dB(A) from 1m distance, which sounds about right for a rack mounted UPS.

27.5 dB(A) for 40mm fan also sounds right, since there are 24V 40mm fans that fall into the same ballpark (just look some Delta fans i linked above).

Are you sure that the voltage does not change when the UPS is on battery or maybe based on temp. I know the fans in my UPS are running but you can't hear them but when it switches to battery under load the fans ramp the speed up. It is very common to change the speed of a fan with a voltage change.

I 2nd that. My CyberPower CP1300EPFCLCD UPS also kicks it's fan on, once power changes from battery delivery. But when running off from mains, fan inside my UPS doesn't spin (since it doesn't need to), making my UPS output noise 0 dB(A).

 

[weeklyCoupons]

The fan noise is louder than anything I have in my 37U rack. It's a fluttering high pitched noise generated by the fan. It sounds like it is off balance and that the blades are rubbing against something or it just the bearings. I've never heard anything like it. It is instantly noticeable over anything in the rack.

Of note, I replaced the fans in all of the switches and routers in my rack with Noctua and the noise coming out of my AV closet is bearable and hardly noticeable.

 

[weeklyCoupons]

Here is a recording of the fan. The thump is me putting my finger on the center of the fan to stop it, then releasing my finger.

https://fastupload.io/V7fZPb78bKoOGBj/file

 

[weeklyCoupons]

So after some testing it appears that the fan does spin at different speeds. I'll need to check out that Delta fan to see if there is a difference in sound.

 

[weeklyCoupons]

1. It's rack mount UPS, in a server rack. I fail to understand why it's operating noise is an issue for you.

It's the loudest fan in the entire 37U rack (I posted a sound clip below). The fan sounds horrid.

1. To be safe, install a fan that can operate up to 24V, while also capable of operating at 12V. The consumer grade Noctua fan, most likely would be blown, once the voltage increases. So, better look towards Delta industrial fans.

There are plethora of Delta fans to choose from, that operate up to 24V and are 40mm in size,
link: https://www.delta-fan.com/catalogse...1&voltage_rated=5700&size_dimension=5648&sku=

Thanks, I'll check these out. Anyone comment on noise levels from these fans?

 

[Paperdoc]

Have you considered the possibility that this fan is old enough to have badly worn bearings, causing all the excess noise? IF that were the case, merely replacing it with the SAME fan would reduce noise while maintaining as-built performance.

 

[weeklyCoupons]

Have you considered the possibility that this fan is old enough to have badly worn bearings, causing all the excess noise? IF that were the case, merely replacing it with the SAME fan would reduce noise while maintaining as-built performance.

This is a brand new UPS. I just thing there is no consideration for fan types when they build/spec these units.

I found a couple of Delta fans that I am going to try out:

https://www.delta-fan.com/AFB0424LB.html

https://www.delta-fan.com/AFB0424MB.html

 

[Aeacus]

This is a brand new UPS.

Brand new, as in you just bought it. But how about the manufacturing date of the UPS? Since it very well could've sat years in store's storage.

Here is a recording of the fan. The thump is me putting my finger on the center of the fan to stop it, then releasing my finger.

https://fastupload.io/V7fZPb78bKoOGBj/file

That link doesn't load for me. Tried with FF and Chrome. Nothing. Perhaps use different file host site?

It's a fluttering high pitched noise generated by the fan. It sounds like it is off balance and that the blades are rubbing against something or it just the bearings.

Could be bad bearing, since stock fan uses sleeve bearing. And if the bearing lubrication flows out of the bearing, it will screech like a pig stuck on a fence. Could be even defective fan without lubrication in the first place.

 

[weeklyCoupons]

Could be even defective fan without lubrication in the first place.

Interesting. How would I go about lubricating it if at all?

 

[bill001g]

Most the ones you try to do this with are fluid bearings which means they use oil. The one you have is a sleeve bearing. It uses some kind of lubricant but it is much less than fluid bearings.

Most are factory sealed and you can't get into them but there are some that have a small cap you can pry off and put oil it in. It tends to be not worth it. I drilled a hole in the hub on one and then patched it with a epoxy. It worked for about a year but it was a strange fan that nobody sold including the manufacture.

 

[weeklyCoupons]

Lovely. I'll just wait for the Delta fans to arrive and will test out a swap at that time.

 

[weeklyCoupons]

Awesome... Finally received the Delta fan, AFB0424LB and swapped out the stock UPS fan.

WOW... Huge difference in sound profile. AV room is now as quiet as it was before I installed this Tripp Lite UPS.

Same level of cooling as well, as referenced by UPS temperature logs.

 

[Paperdoc]

Glad you have a good solution to your problem.

 

[weeklyCoupons]

Thanks for the help.