I still haven't got the top of the penstock to where it should eventually go, but I decided to stick the end of the pipe in the stream where it is and see what would happen.
got about 33psi static on the gauge and tried spinning it up - didn't generate anything except a phenomenal amount of noise - like a foghorn - could here it from 200yds away, but I noticed that if I stuck my finger slightly over then end of the nozzle (to deflect the water in toward the center of the wheel) it was much quieter, so readjusted nozzle for minimum noise.
still no power but initially I thought the motor was turning too slow (I got carried away greasing the bearings - so there was a noticeable resistance in the rotor when turning by hand). Left it running for 10 mins and the rear bearing got slightly warm - so there was too much grease.
Had a bit of a think and felt my initial guess of the speed was out and that it should be generating after all - went back to the house and back fed the motor with 4amps d.c. for about 30 secs and went down an tried again - motor picked up then suddenly dropped in speed like it was loaded - plugged in a lamp and it lit up!
Success!!
I've got a couple of DPDT switches between the 3 100uF caps and the motor:- one swaps the 2C of the C-2C between leading or following the C phase - sure enough the lamp was brighter on one setting. The other switch swaps one of the 100uF caps so it's either in parallel with one cap (100uF/200uF) or in series with the other (50uF/100uF) - the lamp was brighter with the 50/100 setting so stuck with that.
So I went back to the house to check my meters:- with a (230v) 120W lamp plugged in I was getting 150v, 27Hz.
the light was going so I has to go and see to the animals - got back 40mins later and it was now showing 38Hz but the same voltage - not sure why it's changed but maybe some of the grease has melted out of the bearings.
After a while I noticed the frequency had dropped a little and decided to go down the the genny and check things out. Got down there and I could smell something was cooking - genny was OK, but the metal box with the caps in was HOT! as I stood there the genny speed went up like it wasn't loaded anymore and the glow had gone from the window in the house
.
turns out those cheap chinese motor run caps weren't a good bargain after all
even though with a rating of 450v 60Hz they should've been OK).
Oh-well, at lease I know the system is viable, so I can justify the cost of some decent caps and some more pipe to extend the penstock (and some bits n bobs to make another two nozzles)
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