AC Magnetic Analysis

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AC, or alternating current, Magnetic, is the study of magnetic fields due to alternating, or time harmonic, currents. Similar to Magnetostatic, Maxwell's displacement current that couples the electric and magnetic fields is assumed to be null.


In AC Magnetic analysis, the Gauss's law for magnetism, i.e. divergence of magnetic flux density is null, and Faraday's law,, i.e. the induced electromotive force (emf) in any closed circuit is equal to the time rate of change of the magnetic flux through the circuit, are invoked to compute the magnetic field and its related quantities due to alternating electric currents and voltages. It has many practical applications, including:

  • AC Motors and generators
  • Sensors
  • Coils and transformers
  • Inverters
  • Converters
  • Bus bars
  • Inductors
  • NDT and NDE
  • Inductive heating and hardening
  • Eddy current meters
  • Induction motors
  • Eddy current brakes


The AC Magnetic module outputs the following results for each study at each frequency:

  • Magnetic field
  • Magnetic flux density
  • Current density
  • Eddy current
  • Force density
  • Inductance matrix
  • Flux linkage
  • Resistance
  • Impedance
  • Core loss
  • Eddy loss
  • Hysteresis loss
  • Ohmic loss
  • Current
  • Voltage
  • Force
  • Torque
  • Stored energy
  • Temperature
  • Temperature gradient
  • Heat flux

Examples of design issues

The AC Magnetic module can help study a large number of devices and address numerous magnetic and eddy current effects. Below is just a partial list:

  • Minimize eddy current losses and preserve efficiency of many devices that use changing magnetic fields such as iron core transformers and alternating current motors such synchronous motors, 3-phase Induction motors, single phase induction motors, switched reluctance motors, and synchronous generators.
  • Optimize the Non-Destructive Testing (NDT) and Non-Destructive Evaluation (NDE) equipment to better detect cracks and flaws in metallic parts. This technology is typically used in pipe inspection for the oil and gas industries. The aerospace industry also makes use of the NDT and NDE technologies.
  • Optimize the coils design of metal detector to better detect metallic objects such mines, weapons, treasures, etc.
  • Minimize the flux leakage and leakage inductance in transformers.
  • Make sure that heat generated by the power transformer is within the regulatory bodies' requirements.
  • Minimize the skin effect in solid coils.
  • Optimize the force for linear solenoids and the torque for rotary solenoids without overheating the winding.