The KEB COMBIVERT is a frequency inverter with DC-voltage link. The unit is exclusively designed as stepless speed control of three-phase AC motors. Its functionality is based on PWM (pulse-width modulation).

The internal circuit of a frequency inverter contains basically only three stages:

•  a mains rectifier;
• the DC-link;
• an inverter at the output.

The mains rectifier takes the single or three-phase main power supply and via a rectifying bridge converts the AC-voltage into a DC-voltage.

The DC-link role is to smooth the DC voltage via large capacitors. It also contains the inrush current limiting resistor in series to the capacitor to limit the very high currents flow for a short time when the capacitors are empty.

The actual task of the frequency inverter is to produce an output voltage variable in frequency and amplitude for the control of the three-phase AC motor, and this job is taken over by the converter at the output. It creates a 3-phase output voltage using PWM.

The  KEB COMBIVERT, apart of the usual functionality as frequency inverter, is equipped with a very complex control unit, offering  the following features:

•  Autoboost;
• Electronic motor protection;
• Slip compensation;
• Energy saving function;
• Power-Off function;
• Hardware current limit;
• Speed search;
• DC-braking;
• Programmable filter for analog and digital inputs;
• Inputs/Outputs both Analog and Digital;
• Programmable Operator menu.

One of the mid-range unit of the KEB COMBIVERT series is KEB 09.F4.C1D-3420/1.4. The electrical characteristics of the unit are:

• Output nominal power: 2,8 kVA;
• Max. rated motor power: 1,5 kW;
• Output nominal current: 7 A;
• Nominal input current: 14 A;
• Rated operating frequency: 8 kHz ;
• Power loss at nominal operating : 70 W;
• Max. braking current: 7 A;
• Mains voltage:  180…260 V;
• Phases:  1 or 3;
• Mains frequency: 50 / 60 Hz;
• Output voltage:  0…Mains Voltage V
• Output frequency: 0-1600 Hz

Our laboratory offer free diagnosis for all types of electronic boards. We consider that unless we have identified the root cause of the malfunction we cannot estimate the appropriate repair cost. Usually, repairing costs do not exceed 30% of the price for a new motherboard or equipment.

Repair

Our service department ensures complex repairing processes for electronic components. The tasks are professionally administered and executed by well-trained engineers who can perform correct diagnosis and repairing from simple boards to multi-layer PCB (Printed Circuit Boards).

The repairing procedure includes:

• in-depth cleaning of boards
• rebuilding damaged circuits
• building work schemes partly or fully, if necessary
• circuit analysis in order to uncover flaws
• replacing damaged components
• preventive replacement for components that could cause further damage
• software/firmware/bios backup
• delivery towards testing area

Components inventory

The components are being replaced with spare parts belonging to our inventories, but there are cases when it is necessary to import several spare parts directly from the manufacturer/distributor. Our past experience has given us the possibility to build up good communication means with European, Asian and American manufacturers; therefore we also give you the benefit that, in accordance with our contract, we can cover any need of component required by the repair process.

Optional services

On demand, we also provide the following services:

•  Delivering the equipments from/to your address
•  Transportation can be made possible by using any of the following companies: DHL, UPS.