Tuesday, November 6, 2007

Tesla's Trauma and Alternating Current

Nikola Tesla began his univesity education at the Graz Polytechnic Institute, pursuing studies of the subject that fascinated him above all others: electricity.

Tesla was an extraordinary student who frequently enraged his professors, questioning the technological status quo. He rebelled against the generally accepted belief that direct current (DC) was the sole means of delivering electrical power.

It was obvious to Tesla that DC was inefficient and incapable of adequately transmitting power over long distances. There had to be a better way. At the time, an “alternating current system” was nothing more than a theory.

In the middle of Tesla's second year at Graz, his father was felled by a stroke. Nikola returned home, and his father died soon after. Lacking funds for tuition, he took a job at a government telegraph office.

Tesla was upset that his education had been interrupted, but held on to his dream of becoming an electrical pioneer.

It was at this time that Tesla endured an ordeal with hypersensitivity that reduced him to a bedridden invalid. Considering the depressing turns his life had just taken, the bizarre affliction could possibly have been psychosomatic in origin. Whatever its cause, when Tesla finally emerged from the prolonged fugue state, he was armed with a powerful new insight on how AC could be successfully attained.

Sunday, November 4, 2007

The Tesla: SI Unit of Magnetic Field

The tesla (symbol T) is the SI derived unit of magnetic field.

The tesla is equal to one weber per square metre and was defined in 1960 in honor of inventor, scientist and electrical engineer Nikola Tesla.

Some examples for perspective:

A modern neodymium-iron-boron (NIB) rare earth magnet has a strength of about 1.25 T.

A coin-sized neodymium magnet can lift more than 9 kg, and can pinch skin and erase credit cards.

Medical magnetic resonance imaging systems utilize fields from 1.5 to 3 T in practice, experimentally up to 7 T.

To levitate a frog, 16 T is required.

The strongest continuous magnetic field yet produced in a laboratory (Florida State University's National High Magnetic Field Laboratory in Tallahassee, USA), was 45 T.

The strongest (pulsed) magnetic field yet obtained non-destructively in a laboratory (Los Alamos National Laboratory) was 100 T.

The strongest (pulsed) magnetic field ever obtained (with explosives) in a laboratory (VNIIEF in Sarov, Russia, 1998) was 2.8 kT.