Fan blade (FRP)catastrophic failure and drive shaft bent and broke down in cooling tower. 5

[Apsp]

1 fan blade(frp) in A336" diameter fan assembly has been found in catastrophic failure condition and drive shaft(metal) also found in bent and broken condition on ground.
What are the possible root causes??

 

[3DDave]

Based on the extensive detail, I'm starting with Fire ants.

 

[desertfox]

Yep
There isn’t even a picture of the ground it fell on, however how about the Op answer my problem.
I have a 10” diameter frying pan and the handle just fell off what might be the possible causes?

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[Pud]

Oh dear...


Politicians like to panic, they need activity. It is their substitute for achievement.

 

[Artisi]

3DDave is opting for fire ants, I'm suggesting termites.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[MintJulep]

Failures like this often happen when stress exceeds strength.

 

[Jboggs]

Root cause: It broke.


Sorry. I couldn't help jumping on.

 

[MacGyverS2000]

His other thread may provide more detail of the initial situation...

https://www.eng-tips.com/viewthread.cfm?qid=489403

Dan - Owner

http://www.Hi-TecDesigns.com

 

[electricpete]

Good detective work, Dan. That's a little more to go on.

op - do you have a picture of the failed parts? That would be a good start.


=====================================
(2B)+(2B)' ?

 

[MJCronin]

These are the little bastards (Solenopsis invicta) that have a taste for fan blades ...

MJCronin
Sr. Process Engineer

 

[electricpete]

Interesting. At first I thought the fire ants comment was a joke (referencing the lack of information). I knew fire ants could be a nasty hazard to my feet in the backyard, or maybe to electrical equipment, but I would never have guessed they might be a real hazard to machinery (although if it's the same fan that was causing the high vibration in the other post, that vibration did not appear to represent unbalance from fan degradation, based on the oddball frequency recorded).

=====================================
(2B)+(2B)' ?

 

[3DDave]

The most typical effect for fire ants is they have a taste for electrical insulation and they like getting into the gaps of relays. So they end up being part of an electrical circuit and soon become part of a fire. They are low on the list, but given the previous difficulty in gaining information ...

I'm now legitimately wondering if there is a failing VFD that is feeding a really poor quality waveform into the motor and causing the vibration. I can see that leading to fatigue failure of the blade and the imbalance then bending the shaft.

 

[Tmoose]

Is this cell 3 that on or before Nov 18 had "Fan blades already have replaced with new blades.
Drive shaft also has been replaced with coupling and rebalancing has been performed also. But no effect on vibration."
.....................

https://www.eng-tips.com/viewthread.cfm?qid=489403.....................

If so, the workmanship of the repairs AND the possibility of defective new parts must be tossed into the more-than-half-full bucket of possible "root causes".

Seriously, the broken parts and all mating parts and systems have critically important stories to tell.
They speak in pictures, not words (spoken or written).

 

[drawoh]

3DDave,

You silly person. It had to have been space aliens!

--
JHG