KEB Combivert F4 Inverter
KEB Combivert F4 inverter overview:
The power circuit of a frequency inverter consists basically of a mains rectifier. The DC-link and an inverter at the output. The mains rectifier consists of an uncontrolled single or three-phase bridge connection, the single-phase design restricted to small powers. It converts the AC-voltage of the mains into a DC-voltage, which smooth by the DC-link capacitor. Thus in the ideal case (inverter unloaded) the DC-link charged with a voltage of UZK = √2 .UN.
Since during the charging of the DC-link capacitor very high currents flow for a short time which would lead to the tripping of the input fuses or even to the destruction of the mains rectifier, the charging current must limit to a permissible level. This achieved by using an inrush current limiting resistor in series to the capacitor. After the charging of the capacitor completed the limiting resistor bridged, for example, by a relay and therefore only active at the switch-on of the inverter. As the smoothing of the DC-link voltage requires a large capacity, the capacitor still has a high voltage for some time after the disconnection of the inverter from the mains.
The actual task of the frequency inverter, to produce an output voltage variable in frequency and amplitude for the control of the three-phase AC motor, is taken over by the converter at the output. It makes available a 3-phase output voltage according to the principle of the pulse-width modulation, which generates a sinusoidal current at the three-phase asynchronous motor
Specification:
- Type: Inverter
- Power Rating: 11kW
- Supply Voltage: 440V
- Number of phase: 3