OK, for you boat geeks here’s a story about a repair of our hydro-generator. It’s the thingy that we tow behind the boat that generates electricity to augment our solar panel and keep us from having to turn on the engine to charge the batteries.
It all came apart allright. The trick was getting it back together again!
I didn’t honestly think I would be able to repair this thing. I know nothing about even how to open the darn thing up. The company, Ferris Hamilton makes an OK product but my two major complaints are: they have terrible documentation-nothing on how to repair problems and the build quality is mediocre at best. After only two years, this thing looks like it’s twenty years old. It’s incredibly rusty-they used minimal paint to coat it which seems pound foolish for a product destined for a marine environment. I’m going to have to do a proper paint job when we’re back in NZ later this year.
OK, with that said, the thing has been really useful in terms of helping to maintain our battery charge while underway. It tows a propeller behind about fify feet of torque rope in the water behind Charisma that spins a generator that is connected into the batteries. Simple and it allows us to run stuff that we normally couldn’t if it’s cloudy and the solar panels are not charging. But-the generator started turning “hard” a while back and the last passage it just plain almost didn’t turn and make a huge racket. I likened it to a British sports car in low gear. Lots of grinding noise.
I originally thought I would take it to an alternator shop for repair, but several boats here in Savusavu reported such terrible experiences with the local alternator repair guy I decided I would give it a try. If it didn’t work, the thing is heavy enough it would make a great dinghy anchor!
The first step in any project is always unscrew the screws. 😉 There were six of them on the face of the unit. Now remember, Ferris Hamilton has zero documentation on this unit so I had no clue what four of them did. Two held the bracket on, so these came first. Two don’t seem to do anything and the final two actually hold the face plate to the whole thing on. The problem is everything is held on (as it turns out) by the bearings inside the beast that are pressed onto the shaft AND the inside of the face plate. Ouch. The solution: put the bracket back on and hit it with a hammer. The face plate came off and the whole thing was now accessible.
Turns out the problem was; one of the four large magnets inside the main housing had broken loose. Instead of “sticking” to the housing, it was “sticking” to the armature-which is supposed to freely rotate inside the case. Hence the really bad noise.
I cleaned the housing, and the magnet so I could glue them (hopefully) back together and then cleaned up the whatchmacallit that the brushes rub on. They were kinda dirty too. Then I mixed up some epoxy, glued the large magnet back in and crossed my fingers. Actually, I was being very precise about this part. The armature and the magnets have very tight tolerances and if I didn’t glue the magnet back in right it would rub on the armature and voila, a new dinghy anchor would be born!
After sitting overnight to allow the epoxy to dry, I reassembled the whole thing. The other thing I did was add some dielectric grease to some of the screws and the bracket. The factory didn’t do this and there was some electrolysis from different metals contacting each other. They should know better! I also sealed the case with silicone to keep saltwater out. The big trick was getting the bearings inside to reseat properly so I could screw the thing back together. But-somehow it came together and I tested it with my voltmeter. Voltage! It’s also running quieter and more smoothly than it has in a while so I’m guessing this has been in “breakdown” mode for a while.
Oh and the other “I never would have figured this out before” item. There’s a last bit that completes the whole thing. You have to put a brass bushing back on the stainless steel shaft that the torque rope screws onto. This brass piece is pressed on (in my case a hammer is my tool of convenience-this being a boat and not a machine shop). The problem is there are two set screws that hold it on and this piece is what attaches to the torque rope that spins the whole deal. There is no way to align the set screws well enough to screw them through the brass bushing into the steel shaft when you reassemble the thing. After much head scratching I finally got out my die and tap set and re-threaded the whole thing. It worked. The set screws went in.
There’s something about being in-essentially-the middle of nowhere where either you do it or no-one does, that brings out the solutions. I never would have gotten this far on the project back “in the world”, but would have taken it to experts to fix. None here? OK, I guess I’ll have to do it myself. Chalk up another project I’ve never done before.
To paraphrase Mark McClellan from Blue Rodeo has said; “Many of us have now joined the Society of Reluctant Tropical Diesel Mechanics” for lack of more expertise out here in the wilderness.
