Hydro Power 12

Catching up on some of the background on this project.

Since last time, when I was concerned about how long the little permanent magnet motor and castoff pelton wheel were going to last, the system has evolved, and continues to change, however slowly.

Every time the motor/generator would show signs of wear or have a failure, I would manage to get it up and running once again. I cobbled carbon brushes purchased from the hardware store to replace the originals when they wore too small to be usable. The bottom bearing, which supported the armature thrust, was wearing steadily. I would disassemble the motor regularly and lubricate the bearings, clean out the carbon dust and insert shim washers to compensate for the bearing wear, which would cause the armature to ride lower in the casing that it was designed to. This also caused the commutator to wear in a cone-shaped pattern. At one point the armature was running so low in the motor casing that the windings on the armature wore away on the end plate. I dutifully picked apart the damaged windings and soldered in jumper wires to reconnect the windings, making the plant function again, potting that end of the armature in epoxy to hod it together.

It was increasingly obvious that I was going to have to replace this motor at some point, and it would make sense to use something more heavy duty. I purchased a "blue spoon" turgo runner from Hartvigsen Hydro with the intention of getting an upgrade underway. I also purchased a variety of small nozzles to feed water into the runner and a steel arbor that the runner would mount on to allow it to be connected to the shaft of an automotive alternator.

The new runner was going to require a turbine box to mount the generator and nozzle. Turgo runners require that the stream of water be applied at an angle, coming down from the top of the runner, rather than the side, as a pelton runner does. I decided to throw together a small box made of cedar and redwood for a trial, using brass wood screws to hold the parts and pieces in place. I figured that it would be temporary, and I'd build something more sturdy and rot-resistant after I earned more about the runner and the process.

For a dynamo, I had never intended on using a car alternator for such a small amount of power that I could make on the amount of water I had to work with. Instead, I pulled the permanent magnet alternator off of a Southwest Wind Power AIR403 wind generator that I had. It had never proven to be useful in the climates that I had lived in, so putting it to experimental use made some sense.

This is one of the early trials at the house. I'm running the output of the alternator through a random transformer in an attempt to step the voltage up or down to see the effect on the total power output. By the look of the ammeter, I'm putting around 10 Watts into the 24 volt battery bank, a bit less than the PM brush motor, but not bad for a first attempt. A dual Schottky diode assembly is rectifying the output to feed the batteries.

One attractive feature of an AC alternator was the possibility of using transformers or even variable transformers to"tune" the speed of the runner for best efficiency.

Closeup of the turgo runner. The side of the turbine box has been removed to get a close-in look and to help align the nozzle in relation to the runner spoons.

I did end up running a similar plant configuration using this alternator and runner combination for a time down at the lower garden, where the water pressure is better, making around 30 Watts and running the power back to the house through a long wire.

The problem associated with having the plant at the garden was that the water pressure at the house was very low due to the use lower on the line. Gathering some cast-off parts from my storage locker, I built a motorized valve, using the windshield wiper motor from a VW Rabbit (what else?). A controller regulated the speed of the motor, and limit switches told the controller when the valve was either fully open or closed. The intention was to be able to remotely control the valve, so I didn't have to keep running up and down the hill to have enough water pressure for laundry and showering.

In the end I didn't get around to installing the valve before a conservation project to restore salmon habitat on the creek relocated my gravel driveway between the old garden and the house. Without an easy way to get wiring between the two locations, and the fact that the tail water from the hydro plant would make the ground around my new driveway soggy, I shut the plant down and went back to just using the small, original hydro apparatus at the house again.