Sheared Flywheel Bolts on Generator 2

[IOC-AUS]

Hello All,
We recently had a Generator Failure - High Tensile Flywheel Bolts were sheared on the AC Generator.

The Generator Set has been in operation and we understand the system includes Solar.

My question is could this Generator Failure be caused from incorrect Synchronisation.

I would like to understand the Failure and have it explained with logical possibilities.

Any help and advice much appreciated.
Regards, Ian.

 

[TugboatEng]

What the heck is going on in your coupling? It appears to be a keyed shaft that someone has drilled for a flange. Can you please explain?

 

[IOC-AUS]

It is a bit of a strange looking Coupling arrangement- this came from supplier and it seems they use a Rotor with Keyed Shaft (possibly from the 2 Bearing Bare Shaft version) and provide SAE Discs for Direct Couple to Engine Flywheel/Housing.

 

[FacEngrPE]

I suspect bolts were assembled a bit loose, which makes fatigue failure more likely. This is a location where I would only use factory bolts.
Tugboat I have seen this crankshaft arrangement, it is not uncommon, as it costs the OEM less than making two versions of the engine.

 

[desertfox]

From what I can see of the bolts they look like they have sheared, the broken threaded parts look angled which makes me think there was an installation problem, had they failed from a heavy overload then I would expect the broken surface t be more or less flat and at right angles to the bolt axis the bit that’s baffling me is that the keyway doesn’t appear damaged and I would of expected that to have some distortion unless of course there was no key used in which case the load would be directly on the bolts, there does appear to be some circumferential marks on the disc which might indicate some rotational movement until it engaged on the bolt shank.
If the bolts failed in fatigue then I would expect a flat fractured surface with possible beach marks on them but without some close up pictures of the bolts it’s impossible to tell for sure.
We need more information about the failure and how long this thing ran before it failed.

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