Hydroelectric rotor inspection - how often?
Hydroelectric rotor inspection - how often?
(OP)
Hello again.
A little hydro-electric power station with a 1.5 MW synchronous generator has a routine where they take the whole unit apart every year to inspect it. They lift the rotor to see if anything has happened and they also do some cleaning.
I asked them if they ever found anything wrong during these inspections or if the rotor was very dirty? No. Never found anything, never adjusted anything, never changed anything. But they were a bit worried about the bolt-heads. They were getting worn round from these 12 month inspection intervals.
My question: How often would you recommend that the rotor is lifted out of the generator for inspection? Each year? Every fifth year? Never?
Is there any difference between vertical and horizontal machines in this respect? What could happen between inspection intervals?
A little hydro-electric power station with a 1.5 MW synchronous generator has a routine where they take the whole unit apart every year to inspect it. They lift the rotor to see if anything has happened and they also do some cleaning.
I asked them if they ever found anything wrong during these inspections or if the rotor was very dirty? No. Never found anything, never adjusted anything, never changed anything. But they were a bit worried about the bolt-heads. They were getting worn round from these 12 month inspection intervals.
My question: How often would you recommend that the rotor is lifted out of the generator for inspection? Each year? Every fifth year? Never?
Is there any difference between vertical and horizontal machines in this respect? What could happen between inspection intervals?






RE: Hydroelectric rotor inspection - how often?
If nothing is ever found and they really enjoy pulling the rotor, why not make it a 5 year event? I'd be more worried about the wear and tear on the bolts, especially if they are torqued to any appreciable load. The threads could be getting stretched and reducing the holding.
On my vertical units, the rotors obviously come out when the runner needs to come out. At that time, we will inspect and clean.
RE: Hydroelectric rotor inspection - how often?
Any other opinions on this? Is environment a factor?
RE: Hydroelectric rotor inspection - how often?
RE: Hydroelectric rotor inspection - how often?
It would make more sense to check the turbine and bearings on an annual basis. Don't monkey with the generator.
RE: Hydroelectric rotor inspection - how often?
The monitoring system could include shaft displacement, acoustic and accelerometer for cavitation concerns. There is also many suitable pressure transducers available and many on-line generator sensors available to help determine electrical condition in addition to the mechanical and hydraulic concerns.
Skip Hartman
http://www.machinerywatch.com