Control concepts for transformer annealer

In principle, the following methods are available:

  • Voltage control
  • Power control

Common, as with the resistance annealing is the voltage control. For fine-tuning, a program with the following approach has proven itself:

U = U0 + kU ⋅ √v; Uc = U c0 + kUc ⋅ √v

This approach can be used both for the annealing voltage U and for the control voltage Uc. No scaling is required so that the pulse width modulation can be used over a wide speed range. In the voltage regulation, there is almost no diameter dependence.

The power control requires more measuring effort and an additional card and it has diameter dependence. It is also possible to map this control via power in intermediate circle.