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An induction furnace uses electromagnetic induction to
Chapter 31, Problem 80(choose chapter or problem)
An induction furnace uses electromagnetic induction to produce eddy currents in a conductor, thereby raising the conductors temperature. Commercial units operate at frequencies ranging from 60 Hz to about 1 MHz and deliver powers from a few watts to several megawatts. Induction heating can be used for warming a metal pan on a kitchen stove. It can be used to avoid oxidation and contamination of the metal when welding in a vacuum enclosure. To explore induction heating, consider a flat conducting disk of radius R, thickness b, and resistivity r. A sinusoidal magnetic field Bmax cos vt is applied perpendicular to the disk. Assume the eddy currents occur in circles concentric with the disk. (a) Calculate the average power delivered to the disk. (b) What If? By what factor does the power change when the amplitude of the field doubles? (c) When the frequency doubles? (d) When the radius of the disk doubles?
Questions & Answers
QUESTION:
An induction furnace uses electromagnetic induction to produce eddy currents in a conductor, thereby raising the conductors temperature. Commercial units operate at frequencies ranging from 60 Hz to about 1 MHz and deliver powers from a few watts to several megawatts. Induction heating can be used for warming a metal pan on a kitchen stove. It can be used to avoid oxidation and contamination of the metal when welding in a vacuum enclosure. To explore induction heating, consider a flat conducting disk of radius R, thickness b, and resistivity r. A sinusoidal magnetic field Bmax cos vt is applied perpendicular to the disk. Assume the eddy currents occur in circles concentric with the disk. (a) Calculate the average power delivered to the disk. (b) What If? By what factor does the power change when the amplitude of the field doubles? (c) When the frequency doubles? (d) When the radius of the disk doubles?
ANSWER:Step 1 of 7
(a)
Let’s assume the radius of the ring be r with width 
The equation for the resistance of the loop around the disk is given as:
For 
