Crane failures 8

[enginesrus]

https://www.youtube.com/watch?v=nvQuFBMUko4

At the 3:22 area, what sort of material does that look like?
I wonder how many such failures have happened due to the use of the wrong size and type of materials used to construct the crane system?

 

[TugboatEng]

Enginesrus, the coupling did not cause the load to drop. Its construction is irrelevant.

 

[SwinnyGG]

Sigh.

Here we go again.

Will this forum ever stop feeding the troll? I have my doubts.

 

[FacEngrPE]

The coupling broke. There are broken parts not part of the coupling in frame. Without knowing more we can not guess what broke first.
[ul]
[li]I concur with the opinion that a cast iron coupling can be selected correctly for this application (at least per the OEM selection data). (Edit - it looks like a brittle fracture, not all cast irons are created equal)[/li]
[li]I am of the opinion that the use of a cast iron jaw coupling in a hoist, is unwise due to the lack of ductility.[/li]
[/ul]

 

[Cool_Controls]

For what it's worth GGG spheroidal cast iron is pretty ductile Link. But I would also add most hoist designs account for the possibility of coupling and gearbox failures.

 

[TugboatEng]

The incident happens in Harculo. There really isn't much information out there other than lots of speculation. Some observers noticed the crane is rated for 60 tonnes and comments say the rotor is 70-75 tons. I would be surprised a turbine hall would have a crane that wasn't rated to lift the turbine.

 

[FacEngrPE]

This accident ?? October 17th of 2003 at the Harculo Power Plant Netherlands.

http://overheadmaterialhandlingregulation.blogspot.com/2011/09/harculo-crane-accident.html

https://www.reddit.com/r/ExpensiveA...0/failure_of_overhead_crane_at_the_attempted/

Over capacity lifts are never a good idea. Different location, simalar scenario ,

INVESTIGATION OF THE MARCH 31, 2013 TEMPORARY
OVERHEAD CRANE COLLAPSE AT ARKANSAS NUCLEAR
ONE POWER PLANT IN LONDON/RUSSELLVILLE, AR
____________________________________________________
U.S. Department of Labor
Occupational Safety and Health Administration
Directorate of Construction
August 2013 LINK

 

[spsalso]

This video, referenced in one of the links above:

https://www.youtube.com/watch?v=axjmK_vjYCM

shows a bit more information(and more clearly). At 3:01, there's a shot of a "void", up in the crane structure. On the left, there appears to be a motor, and the remnants of a brake. On the right, a gearbox. And nothing in between. The span distance between the two elements is interestingly long. Maybe two feet.

One could wonder if there was a brake on the gearbox output.


The crane capacity is clearly shown in another shot: 60000 kg.

I suspect the weight of the rotor was known, since it had to be transported; and the transporting entity would be very interested in that number.


spsalso

 

[TugboatEng]

It looks like the spreader bar capacity is 60kkgs. Perhaps the crane really was overloaded.

 

[spsalso]

Ah, yes. At 2:55, there is a photo of the spreader bar, and up towards the top; there appears to be that tag I saw earlier. And mistook for a tag from the crane, itself.

"werklast 60000 kg" = workload 60000 kg

"eigen gew 9000 kg" = own weight 9000 kg


So there's the weight of the rotor plus the weight of the spreader. And we don't know the crane capacity.

However, it doesn't appear the spreader bar failed. "Falled". But not failed.

The turbine blades, at least in one picture, appear to be single units. So only the damaged ones need replacing. Save a few bucks, there.



spsalso

 

[LittleInch]

There is remarkably little info out there, but I guess it was 2003.

Brake failure is mentioned in passing in one report, but no details I can find on anything technical.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LionelHutz]

I wonder how many such failures have happened due to the use of the wrong size and type of materials used to construct the crane system?

Do you have any clue at all why this one failed, or is this just more of your random "everyone builds everything wrong" crap?

 

[SwinnyGG]

@LionelHutz: It's the second one

 

[Cool_Controls]

At 3:01 on the left side is definitely the remains of a thruster actuated drum brake, clearly the the gearbox shaft failed. So was there a backup brake on the output side of the gearbox? The intresting thing about hoist brakes is that 99% of the time they are only a holding brake, the motor does the braking. It's only e-stops and other faults that would result in the brakes having to perform dynamic braking, which means if your brakes are not well maintained you can get yourself into a situation where the brakes hold just fine but fail in a dynamic situation (when you really need them to perform)

 

[Brian Malone]

Cool Controls and Spalso, does this screen grab show the area you are describing as the remains of the drum brake?

 

[Cool_Controls]

Yes

 

[Brian Malone]

Cool Controls - so there is a good possibility failure of the braking system which would have been in use by the crane operator as the rotor was being eased into place changed an uneventful installation into a major loss. In one of the links in the comments it is mentioned the facility was being unmothballed so there is a possibility the braking system had not been receiving regular maintenance - thus being in line with the cause for failure you have described. The lovejoy-type coupling shown with damage was collateral.

 

[spsalso]

The crane was likely used to remove the old rotor, not terribly much earlier.

I don't see how that brake failing would cause the coupling shaft to disappear.



spsalso

 

[TugboatEng]

One thing strange, the video shows every moment of the lift except for the moment the crane fails. When the video cuts back in the load is already dropping.

 

[spsalso]

I think it DID show the "moment". Starting at 1:48 (of the new and improved video that I linked), the rotor is being lowered. A second later, there's loud noise, and the rotor falls.

That's the "moment". A few seconds before and after would have indeed been nice.

Interesting that the Dutch/Euros feel no need to inform the public about how this happened. Move along folks; nothing to see here.


spsalso

 

[TugboatEng]

Listen to the sound. When the video cuts in the sound is already very different than any other part of the lowering. That is why I believe the failure began before the video.