Hydro Power 11

Time for some unscheduled maintenance. Last week, I went out and turned on the plant at dusk in preparation for the evening's lighting. About nine o'clock, I noticed that the plant wasn't putting out any power, as indicated by the dedicated ammeter inside the Housetruck. "Great" I thought, "the spring has quit again, I'll have to trudge up the hill again tomorrow and get it put back into shape", and got on a coat to go out and switch the house and truck over to the backup water supply.

When I got outside, I could hear that the water was running full on at the plant, but it didn't sound quite "right". Looking at the plant revealed that although the water was blasting the pelton cups, they weren't rotating. I reached underneath the plant and gave them a twist. It was stiff, then started spinning of it's own accord. I just assumed that since the weather was below freezing, I just had some ice buildup somewhere that prevented the plant from starting up, and I just hadn't noticed.

This morning, I went out to shut the plant down when the batteries looked like they would get filled by the PV array, and found the plant stalled again. This time I know it was running, because I had checked for charge current when I got up. Obviously, something was binding inside the generator, and putting enough load on the shaft that the pelton had been unable to supply enough power to keep it turning. Time to investigate.

Just at dark tonight, I went out to turn the plant on, and decided it was the right time to find out what was going on. I removed the plant using the pipe unions, unplugged the electrical wiring, and took it into the garage. I was afraid that it would be a rusted-solid block of corrosion, but amazingly, it all came apart easily. I attribute this to all the lithium CV joint grease that I slathered on all the exposed surfaces, motor shaft, etc before I assembled it last time.

Inside the motor/generator, I found that the brushes were worn almost all the way down (no surprise), and that the motor case was well filled with carbon from the brushes. The front (shaft) end of the motor seemed to be very stiff in the sleeve bearing, so I completely disassembled the armature and end plates, cleaned everything up, and relubricated the bearings. I also chucked the armature up in the drill press and used some emery cloth to polish up the commutator.

Nothing to do about the worn brushes, they still had a few hours left on them, so I reassembled the motor, put it all back into the housing and reassembled the pelton runner, etc. After it was done, the motor shaft turned freely and had no sticky spots.

Putting it back online brought it up to full output, and it runs quieter than ever. Next time I go to the city, I'll have to stop by the motor shop and see if they have any brushes that can fit this motor, or something that can be modified to fit. If I can replace the brushes, I think I can get another year and a half out of this thing.