Empirical Verification of a Short Coil Correction Factor
(English)Manuscript (preprint) (Other academic)
The magnetic field produced in the air-gap by any particular 'short coil' at a fixed current, is affected by a highly complex interaction of the coil and work piece geometries and changes in frequency. A frequency modified semi-empirical short coil correction factor, based upon the formula published by Vaughan and Williamson in 1945, is presented and experimentally verified. This new equation is shown to predict the total system reactive power and the average magnetic flux at the surface of the work piece with typical differences of less than 2% at 50 Hz AC and to accurately predict work piece heating rates typically within 5% for aluminum billets at 50 Hz to 500 kHz AC. The work piece real and reactive powers, and total system reactive power are compared with both analytic and 2D axial symmetric FEM model solutions, as a function of operating frequencies from 50 Hz to 500 kHz. Measured flux density is compared to FEM and analytical predictions at 50 Hz.
Coils, Induction heating, Magnetic fields
IdentifiersURN: urn:nbn:se:kth:diva-123782OAI: oai:DiVA.org:kth-123782DiVA: diva2:630111
QS 20132013-06-182013-06-182013-06-18Bibliographically approved