Dust flux, Vostok ice core

Dust flux, Vostok ice core
Two dimensional phase space reconstruction of dust flux from the Vostok core over the period 186-4 ka using the time derivative method. Dust flux on the x-axis, rate of change is on the y-axis. From Gipp (2001).

Saturday, November 6, 2010

Close-up with copper

In the back alleyways of SCC, about 50 m north of the main highway out of Accra (to the west) is an unnamed transformer workshop. There, old burnt-out transformers are unwound by hand, and new transformers are built.

Shop owner in foreground. The fellow behind him is unwinding a voltage regulator.
All right--the place doesn't look like much. Maybe you wouldn't feel comfortable buying a transformer from such an establishment in Toronto or wherever.

Isn't that beautiful?

The old copper wire is sent off to be melted down and is drawn out again. I didn't ask if they ever used pennies. They check gauge with a micrometer and their work standard is really good. It just takes awhile to receive a product.

We went to see them about building a three-phase step down transformer. We have this submersible slurry pump which we brought over in 1997 and used from an American vessel--it ran on 208 V 3-phase power. We have a newer pump arriving shortly by sea, and the local generator we picked up for it provides 380 V three-phase power. While waiting, we would like to use the old pump.

Apprentice unwinding the voltage regulator.

We went over the circuit diagrams for the transformer we wanted. He was willing to price and acquire the materials and dielectric oil and seal the whole thing up at a reasonable price. But that hand winding--it would take a week. He was willing to guarantee the work.

Reluctantly we decided to assemble one ourselves using store-bought transformers, stepping down the phases separately and recombining them. We successfully tested the contraption yesterday and are spending the next couple of days getting it field ready for deployment next week.

Three phase transformer. Inelegant, but it worked once we replaced the fuses that came with the transformers with the ones which should have been supplied.

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