Theoretical Modeling for a Kind of Electric-magnetic Drive System

AC current-carrying coil has a repulsive force produced to which a metal plate approaches. But how to calculate the force magnitude and what’s the primary cause for the repulsive force is not very clear nowadays. Besides complex existing methods, the paper provides another newer effective way to solve the problem. That’s both suitable for low-frequency and high-frequency wave coil and its nearby metal plate. It can also interpret why the electric-magnetic drive system generate force in the space. That is an enormous progress over the deceptive electric-magnetic drive system.