The mutual inductance and induced currents between a single turn primary and twenty turn secondary coil in a concentric coplanar arrangement is computed using a frequency domain model. The secondary coil is modeled using a homogenized approach which does not explicitly consider each turn of the coil. The results are compared against analytic predictions.
A capacitor with an applied sinusoidally time-varying voltage difference is modeled. A wide frequency range is considered and the impedance of the device is computed. Solver accuracy is addressed. The relationship between the frequency domain impedance and the steady-state capacitance and resistance of the device is discussed.
The induced currents in a copper cylinder produce heat that in turn change the electrical conductivity. This means that the field propagation has to be solved simultaneously with the heat transfer through the cylinder and surrounding system. This model shows this coupling between eddy currents and heat transfer as a tutorial example.
This model shows how to combine an electric circuit simulation with a finite element simulation. The finite element model is an inductor with a nonlinear magnetic core and 1000 turns, where the number of turns is modeled using a distributed current technique. The circuit is imported into COMSOL Multiphysics as a SPICE netlist, which merges the inductor model and the circuit elements as ODEs.
This is a tutorial how to set up electric machinery in 3D using a combination of the magnetic fields and magnetic fields no currents interfaces.
A cylindrical magnet falling through a copper tube induces eddy currents on the tube walls, which in turn, create a magnetic field that opposes the magnetic field of the magnet and induces a braking force that opposes the motion of the magnet. This model computes the velocity of the magnet after it is dropped, as it reaches its terminal velocity at which the magnetic braking force equals the ...
A magnetic brake consists of a permanent magnet, which induces currents in a rotating copper disk. The resulting eddy currents interact with the magnetic flux to produce Lorentz forces and subsequently a braking torque. This 3D problem is solved using a stationary formulation for the electromagnetic field coupled to an ordinary differential equation for the rotational rigid body dynamics. ...
This model considers a square inductor that is used for LC bandpass filters in MEMS systems. The simulation calculates the self-inductance. The first step in the modeling is to compute the currents in the inductor. These currents are the source for the magnetic flux computations, carried out in a second step.
This model shows a setup of two parallel wires with a constant current running through both. Their cross-sections are successively reduced until a set force per unit length is reached.
A transient model of a capacitor is solved in combination with an external electrical circuit. The finite element model of the capacitor is combined with a circuit model of a voltage source and a resistor. A step change in voltage is applied, and the transient current through the capacitor is computed and compared to the analytic result.