| I had the opportunity to work at a 1.4 meg hydro plant last summer with my friend Mark who runs the plant.
First the specs
The hydro has 2 diversions, on two seperate creeks, they join in a settling tank, then start thier 2.1 mile journey down the penstock. the penstock begins at 24 inch diameter, necks down to 20 inches, and finally to 18 inches for the bottom .75 mile.
- ft total head.
- 7 Cu Ft/Sec flow.
The alternator is a 8 pole 900 rpm 3000HP 4160 volt 3 phase induction motor made by Cato Engineering. it is inseresting that it only has 8 RPM of slip, at full power it runs at 908 rpm.
That is me standing in front of the generator.
That is the Pelton runner in front of the alternator.
The reason the runner had to be replaced is, there was a grid failure and the deflectors failed to drop into place in front of the nozzles. The nozzles take 3 minutes to close. The resulting overspeeed cracked the runner through the keyway. The cracked runner was run for the rest of the season at reduced power while a new one was cast. The new runner was cast from the wrong alloy, and subsequently work hardened and was shedding entire cups under load after a few months, so the original runner was welded and re-ground and put back into service while a 3rd runner was cast from the right alloy. These pictures are of us replacing the welded runner with the final new one.
Here is my hand inside one of the cups for scale
We had to pound the coupler on to the 5 inch shaft with this white oak log hung from the ceiling, the new shaft was a few thousandths larger than the old one.
It took 3.5 hours to get it all the way on. Heating the coupler didn't help at all.
Dustin |
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