Wednesday, January 9, 2013

Wire Exciters Are Awesome


This morning I woke up feeling like a million bucks.  I set up my hammock outside to escape Mike's snoring, and even though I was woken up by a squawking peahen it was probably one of the best nights of sleep I've ever had in Africa.  Not one mosquito bite, either!

Sleeping Easy
We discovered that our generator had been broken while we were out of country.  This was mildly frustrating, but considering our drill is locked away where we can't reach it, the generator wouldn't be much use anyway.  We put these issues aside, and dived headlong into addressing the electrical system issues we had diagnosed yesterday.

One of the biggest problems I anticipated was that we only had a foggy idea of where the wires running from the ferrocement tank float switches back to the wet well controllers were located.  I had spent many hours helping my dad locate breaks in the invisible dog fence around my parents' yard, and it was never fun.  With roughly 4km of underground wire in Cameroon, I was even more apprehensive.  I recently picked up an underground wire exciter for $50 from Brackmann Engineering.  While something much fancier would have been nice, we have a limited budget, and I was fairly confident it would do the trick.  It basically works by sending an AM radio signal down the wire, and then you can use a portable AM radio to locate the wire to within a 5 feet or so.  It's not super precise, but it's good enough for wire finding, and great for determining if there are breaks in the line.  It was pretty fantastic Christmas present for my dad which I immediately confiscated and took to Cameroon.  Dad, if you're reading this, I promise to bring it home and help you fix the dog fence again.  It should be easy this time.

While Felix the plumber, repaired a leak in some of the plumbing at the top of hill, I repaired a break in one of the float switch lines.  Most wires, are not designed to be exposed to the elements, and unfortunately, this wire had not been properly sealed/waterproofed in conduit and buried.  Because it wasn't buried, it was a fairly straight-forward repair.  Before completely sealing the lines, I also used the wire exciter to determine if there were any other breaks in float switch wires, and was very happy to find that they were functioning as expected.  With the help of Mike and Erica, we have already GPS mapped the path of one of the wires, and given time and a machete we hope to map the other two lines.

After completing the repairs to the float switch wires, we turned our attention to repairing the faulty controllers.  At Bakang 2 wet well we swapped in a brand new controller and determined that the pump was functioning perfectly and that the controller was indeed faulty.  Since the old controller seemed to have limited functionality we decided we put it back in place and took the new controller to Balatsit 2 to replace the controller that was seemed to be completely non-functioning.  After making the replacement though, the CU-200 presented an F3 error, indicating no connection to the pump.  Some diagnosis using both the wire exciter and a wire toner indicated that there were connections all the way to the bottom of the pump (where the wire enters the pump housing).  Measurements of the resistance through the pump indicated that there was still a connection through a motor coil in the pump.  It's a perplexing problem that may require us to pull the pump from the wet well to check all connections.

While we did this work Dr Steve and Felix went around installing the new push taps at all the tap stands.  The new taps are wonderfully simple, and should prevent water waste, while also preventing the spread of germs from the tap to the water.  Almost every tap stand we visited on Tuesday had dripping, leaking, or left-open taps.  The new taps should really prevent this.  Even the youngest kids were quickly able to understand and use the taps.

We ended up heading back to the Mayor's house relatively early at 4PM, so that we could test a broken pump.  I had done this previously back in the DE so the process was fairly straight-forward, but as always some in-country ingenuity was required so that we could plug in the pump directly to mains power and submerge it in a make-shift wet well.  Resistance measurements of the pump indicated an open circuit, and it wasn't much of a surprise that when we did hook up the pump it didn't work.  Little Guy (one of the little boys who lives at the Mayor's house) seemed somewhat disappointed we were unable to soak him with water.
Using local materials to make a VERY leaky testing wet well.
Dr. Steve left us to test the pump while he tried to use the local internet cafe (again).  We have some exciting guests expected for the hand-off ceremony on Monday, and Dr Steve is busy orchestrating things as best as possible with limited internet.

As I write this post, Mike and Erica are busy cutting aluminum to replace some parts of a couple racks, and Dr Steve is reviewing video and photos we've been taking.

Tomorrow the metal man (welder) will be helping us remount the float switches while most of the team plans to attack the Balatsit wet well.  Assuming the pump is not completely broken and we can get it pumping again, the entire 6 pump system will be working and we will be leaving the system to the community in working condition.  It will be no small feat, and has taken 10 trips, 6 years, and a lot of hard work by many dedicated people to make it happen.  Crossing our fingers!

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