How to Make a Axial Fan Survive 1 Year in 99% Humidity at 25°C? - Page 1
Forum section: electronics / beginners

author: Richard1130
author_rank: Newbie
timestamp: April 24, 2025, 02:25:01 am
content: Hello everyone,I'm currently testing the durability of EC fans in high-humidity environments and I'm looking for advice or suggestions on how to improve performance.Here’s my setup:Fan model: 80x80x38mm, EC 48V, Plastic body, and impellerProtection: Shaft core sealed with waterproof potting compoundTest conditions:Group A: 3 fans in a chamber with 99% humidity, 25°CGroup B: 3 fans in a chamber with 25% humidity, 25°CGoal: Continuous operation for 1 yearResult: The 3 fans in the 99% humidity chamber began to fail one by one after around 200 days of operation.I suspect moisture is still penetrating into critical parts of the motor or bearings despite the waterproof potting. Has anyone dealt with similar conditions? Any tips on structural design changes, coating methods, or material choices to improve long-term humidity resistance?Your suggestions or any shared experience would be greatly appreciated!https://www.hdhfan.com

author: wraper
author_rank: Unknown
timestamp: April 24, 2025, 02:38:23 am
content: I'd avoid using ball bearing fans for this.

author: Richard1130
author_rank: Newbie
timestamp: April 24, 2025, 02:46:35 am
content: Indeed, upon disassembly, we found signs of rust on the ball bearing.

author: thm_w
author_rank: Super Contributor
timestamp: April 24, 2025, 11:42:25 pm
content: What do you mean by "waterproof potting compound"? Its a cured silicone? If so there will still be a gap for the rotating element, you'd need a o-ring seal or something more advanced.But instead of doing that, why not just look at off the shelf IP55, IP65, IP66, etc. rated fans?https://yccfan.en.made-in-china.com/product/WxyUwKAPgYka/China-Waterproof-IP66-24V-120X120X25-Cooling-Fan.htmlThe manufacturer might tell you what kind of tests they run, if the PCB is potted, etc.Another option would be to use a magnetic coupling, but, thats probably only needed for actual water pumps.

author: TERRA Operative
author_rank: Super Contributor
timestamp: April 25, 2025, 04:48:18 am
content: I remember years ago when I was working as an electrician, we would source fans (Papst etc IIRC) from RS Components that were environmentally 'hardened' (I don't remember the actual nomenclature) when we replaced the cooling fans in outdoor kiosks (think things like the security beeper boxes for boom gates and the like).They seemed to last a long time in the humid subtropical climate of Brisbane, Australia.

author: amyk
author_rank: Super Contributor
timestamp: April 25, 2025, 05:15:07 am
content: Pack bearings with grease.

author: Richard1130
author_rank: Newbie
timestamp: April 25, 2025, 08:45:12 am
content: The waterproof potting compounds are materials used to encapsulate electronic components. In fact, the waterproofing is very good, but I don't know how moisture can get in. Thank you for the advice tho.

author: Richard1130
author_rank: Newbie
timestamp: April 25, 2025, 08:47:29 am
content: Thank you for the advice.

author: tooki
author_rank: Super Contributor
timestamp: April 25, 2025, 09:09:14 am
content: Quote from: Richard1130 on April 25, 2025, 08:45:12 amRight. Potting compound is a type of sealant for non-moving parts. But the part that rusted is the ball bearings, which aren’t potted. (And can’t be; if you potted them they wouldn’t be able to move.)Quote from: Richard1130 on April 25, 2025, 08:45:12 amWell clearly the waterproofing isnotvery good.Why not ask a reputable fan manufacturer about fans for a very high-humidity application? This is hardly an unusual situation, all things considered. Just make sure it’s a fan manufacturer that doesn’t only specialize in PC fans. You want a company like Papst that makes fans and motors for all kinds of applications, including refrigeration, HVAC, and industrial stuff.

author: Tina wang
author_rank: Newbie
timestamp: April 27, 2025, 03:36:32 am
content: Your test requirements are very similar to those of one of our German customers. You can choose a more professional fan from HDHFAN.https://www.hdhfan.com/

author: wraper
author_rank: Unknown
timestamp: April 27, 2025, 03:46:58 am
content: At 25oC you don't even need ball bearings for long life. Sleeve bearings will last a long time at such temperature, not to say there are other longer life variants such as Sunon Vapo/Maglev, FDB bearing and similar which prevent lubricant loss and have similar or even longer lifetime than ball bearings unless operated in hot environment.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 27, 2025, 04:08:29 am
content: While I agree that ball bearings probably aren't required in this application, many rust resistant versions of ball bearings are available. Stainless steel, plastic and ceramics with variants in each of those major categories. One thing that is overlooked is that rust resistance must be built into all components. Things like retainers, shields and seals, not just the balls and races. This will also apply to bushed bearings. The bushing can be rust resistant, but if the shaft is not also resistant failure can come more quickly than expected.Another thing which tends to limit life in hot humid environments is mold. The usual approach to controlling that is sealing as you are doing, and fungicidal additives to materials. I don't know if or how that is done these days, but suspect it involves some very cautious navigation between environmental regulations and effectiveness.

author: Tina wang
author_rank: Newbie
timestamp: April 28, 2025, 01:27:46 am
content: Good idea

author: BrianHG
author_rank: Super Contributor
timestamp: April 28, 2025, 01:34:05 am
content: Thick water-resistant lithium based grease.However, only expect around 1-2years if you run the fan continuously in that 99% humidity environment.

author: coromonadalix
author_rank: Super Contributor
timestamp: April 28, 2025, 06:01:08 am
content: you have ceramic / diamond strength based bearings

author: Coordonnée_chromatique
author_rank: Frequent Contributor
timestamp: April 28, 2025, 07:19:56 am
content: Quote from: Richard1130 on April 24, 2025, 02:25:01 amHello, you haven't say what failed !

author: Jeroen3
author_rank: Super Contributor
timestamp: April 28, 2025, 08:38:26 am
content: Are you using the fans in their intended orientation? Not all fans can be used in any orientation.

author: SteveThackery
author_rank: Super Contributor
timestamp: April 28, 2025, 10:28:13 am
content: Quote from: Richard1130 on April 24, 2025, 02:25:01 amQuote from: Tina wang on April 27, 2025, 03:36:32 amIs there something weird going on here? Advertising for HDHFAN? Or just a mistake?

author: CaptDon
author_rank: Super Contributor
timestamp: April 28, 2025, 12:48:56 pm
content: You buy a fan with a completely sealed motor which drives the fan through a magnetic coupling similar to pumps made for toxic or hazardous materials. The support bearings for the fan are also completely sealed. Look at the typical old style car air conditioning compressor which has a shaft to the outside world but contains freon internally to an idle pressure of at least 40PSI. The magnetic coupling is in common use in chemical stirrers and fish aquarium filters but is also available for fans used in explosive environments. Price you ask, about the same as a used car!

author: amyk
author_rank: Super Contributor
timestamp: April 28, 2025, 07:37:00 pm
content: Quote from: SteveThackery on April 28, 2025, 10:28:13 amIf it's advertising they are doing it badly, as they are implying that their fans fail quickly and need help from others to try to fix it...

author: SteveThackery
author_rank: Super Contributor
timestamp: April 28, 2025, 11:29:13 pm
content: Quote from: amyk on April 28, 2025, 07:37:00 pmYeah, I agree. I think @Tina wang didn’t realise the OP hadhttps://www.hdhfan.comas his sig.

author: alpher
author_rank: Frequent Contributor
timestamp: April 29, 2025, 12:17:08 am
content: In my experience (beit at a little higher temperatures ~35C and humidities of 90%+) no axial fan will last more that a couple of years at best. Just use what's proper at these conditions, a proper stainless steel blower (or moisture resistant plastic) with motor being outside of airflow.

author: jh15
author_rank: Frequent Contributor
timestamp: April 29, 2025, 12:21:26 am
content: Only a year? another to be thrown away or subscription serviced device?