Grenada - Transformer #4

[Kevin's Post]It's been a while since we've talked about our electricity woes, so here's a quick recap: The power supply at the marina is 220 volts (actually closer to 200, but I'll get to that) and 50 Hz, our boat is American and needs 120 volts 60 Hz. So, after our first week having no power, the marina cannibalized a 3 kw transformer (Transformer #1) from the laundry room and gave it to us. This transformer was too small and couldn't provide enough current to start our air conditioning compressor. So we gave it back. Then they gave us a 15 kw transformer (Transformer #2) and life was good. For a few days, anyway. Then they took it away from us and gave it to a bigger boat (which by the way is now unoccupied). Then they gave us another 3 kw transformer (Transformer #3) which can provide enough current to start our air conditioners. Unfortunately transformer #3 only produces 92-96 volts under load, which is bad for the compressors (at 50 hz, the nominal voltage is 100). After learning that these transformers only cost about $150 in the states we decided to just buy our own (transformer #4). We had it shipped from the states to Grenada which cost $250. By the time it arrived it had so many broken parts inside that it sounded like a 30 pound maraca. Needless to say, it didn't work and we filed a claim with FedEx.

The reason we ordered this particular transformer is because it has an automatic voltage regulation circuit in it and can take any voltage input from 160 volts - 250 volts and produce the correct output. You can even adjust the output +/- 10 volts. So, if it worked it would have compensated for low input voltage automatically. But it didn't work. After starting the claims process with FedEx, it was clear that they weren't interested in owning a broken transformer, so I decided I had nothing to lose by trying to fix it. Hey, I've been using electricity all my life, right? How hard could it be? So I took the whole thing apart, sketched out a wiring diagram, fixed the broken pieces, bypassed a broken switch, and managed to put the whole thing back together. I hardly had any parts leftover. I cautiously plugged it in, half expecting it to explode or at least burst into flames. Anyway, it didn't and now I believe it is working like it is supposed to. It has two output sockets, one for 110 and one for 220. On the 110 socket I am getting 110 volts between hot and neutral which is good. However I am also getting 110 volts between neutral and ground which the boat's electrical panel interprets as reversed polarity and so it won't let me flip on the breaker. So the 110 socket is useless. The 220 socket works great though, even with a 200 volt input I can adjust the output to be anywhere from 210 - 230. So I am running the regulated 220 output from transformer #4 into transformer #3 to step it down to get a steady 100 volts, exactly what the air conditioning specs call for at 50hz.

After all this, today the marina owner told us that starting tomorrow he is converting the marina power to 3-phase in order to solve the low voltage problem, thus making our new transformer nothing more than a $400 sacrifice to the transformer gods.