ELCA - Electrocolouring Static Power Supplies Unit
A new generation electronic power supplies; for modern Aluminium colouring: Three phase supply. Full solid state control (no moving parts). DC / AC output mode. Programmable AC waveform (also not symmetrical output available). Computerized full digital control.
The colouring process
It is known that in order to colour anodised aluminium it is necessary to use equipment able to supply an alternate waveform , with adjustable amplitude generally up to 25 Vdc. Also a DC phase before colouring can be necessary.
Full solid state suppliers
This kind of power unit offers several advantages in comparison with the single phase electromechanical suppliers.
The full solid state unit is suitable to be supplied by a 3 phase AC line (therefore without any current unbalance)
Thanks to semiconductors and control circuits available nowadays the power control system can now be manufactured assuring good working reliability and without any periodic maintenance.
DC Phase
The three phase supply voltage is lowered to a proper value by means of a power transformer (without mobile contacts). The transformer secondary voltage is rectified to obtain a direct voltage / current. Then the output voltage / current fed to the load is adjusted and properly smoothed by means of a proper smoothing filter.
The direct voltage can be used during the first phase of the process.
AC Phase
During the colouring phase, the polarity is periodically reversed (according to a preset program) in order to obtain an alternate voltage with the requested value and waveform; moreover, the unit is able to adjust independently the duration of positive and negative half waves.