There is described a power circuit (10) to supply and control at least one heating element (5), having a single-phase resistive load in alternating voltage, the circuit (10) having a three-phase alternating voltage source (6) comprising: a rectifier (3) suitable to transform the alternating voltage of the three-phase source into a single-phase direct voltage; a frequency converter (4) suitable to transform the single-phase direct voltage into single-phase alternating voltage for the heating element (5); a PLC suitable to control said frequency converter (4), according to a periodic sequence of alternating active phases and recirculation phases such that the effective voltage output from said converter (4) can be regulated by varying the duration of said phases.
The power converter transforms the alternating voltage of the three-phase source into a continuous single-phase voltage downstream of the diode rectifier bridges (3), at the working frequency of the furnace. The single-phase continuous voltage, through a special frequency converter (inverter) (4), is transformed into a alternating single-phase voltage suitable for feeding the induction furnace (7). The circuit further comprises a control unit, not shown in the figure, capable of controlling the inverter in such a way as to provide a desired frequency and single-phase voltage value, downstream of the converter.
GMS designs and manufactures IGBT converters with frequency ranges from 50 to 4000Hz and power output up to 15MW designed for powering MF, BF and CH channel inductors in single or multiple configurations. The same technology is also applied for induction heating, single-zone or multi-zone.
GMS converters are designed to guarantee to the client:
- Variable frequency and electrical power feeding through IGBT converter set.
- Very good value of the cosphì during all the condition of the working cycle.
- Current Harmonic Index.
- 12/24 Pulses Converter Configuration.
- Power sharing capability.
- Optical Fiber data transmission.
- Remote control of the machine by Internet.
- Low investment costs.