The fluxes [[PHI].sub.12](x, [x.sub.1], t) and [[PHI].sub.21](x, [x.sub.1], t) are the mutual magnetic fluxes of the two

induction coils in one TCR antenna and can be expressed as [25]

Figure 1 shows part of the molten metal pool and part of the

induction coil, distributed in relation to the vertical axis of symmetry.

With the

induction coil open (digital voltmeter, or DVM, very high impedance), there is virtually no current flow, and thus, no significant term for energy lost to resistive heating.

The ring-shaped multi-turn

induction coil was produced from copper pipe in the form of a spiral.

Using the developed simulation model, the initial computations were performed applying the operation frequency of 25 kHz with the aim to define the current density in

induction coil necessary for the formation of a good joint.

The fundamental operational difference between the two is the rate at which each applies power to the

induction coil under varying conditions.

Conventional methods of surge protection--like an

induction coil in a line, for example--exact power losses.

The topics discussed included induction heating basics, power supply choices,

induction coil designs and applications, induction heating problems and solutions, quench process and distortion control, unique applications, and many others.

This calibration step incorporates a high quality voltage reference (in practice a Josephson voltage standard), and uses the force coil as an

induction coil. If the force coil of an ampere balance is moved at constant speed v through the magnetic flux gradient produced by the second coil, then a voltage V is induced across it.

The

induction coil can be shaped to match the contours of the cavity, and the nature of induction heating--it is effective mainly for heating surface layers as the electromagnetic wave decays as it penetrates the conductor--suits it particularly to cavity surface heating.

Both the energy input and necessary impeder cross-section can be reduced by one of the following setup changes reduced vee angle (a 1.5[degrees] reduction in Vee angle equals a 100 kHz step down in frequency (Asperheim & Grande, 2009), less spring-back, shorter distance from

induction coil to weld point.