70 Ton Electric Arc Furnace (EAF) at Nucor Steel - Auburn, NY
Three graphite electrodes, one for each AC phase, are lowered into a furnace full of cold scrap. This is the beginning of a "heat", or batch, of steel.
The initial strikes are sudden and deafeningly loud as the arc extinguishes and relights. Electricity tries to find a path phase-to-phase through the conductive steel scrap.
Resistive heating is enough to melt 70 tons of steel to a liquid up to 3,000+ degrees F, depending on alloy, in 30 minutes.
Typical furnace power is 38 megawatts. That's right, MW. Nominal voltage is 720 VAC , and current is measured in kiloamps. This initial phase is very demanding of the local power grid, and many mills, including this one, have on-site capacitor banks to dampen the massive current changes and limit "flicker", or disturbances to local residential and commercial service.
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