KEB-COMBIVERT inverters are frequency converters used in a wide range of industrial applications. Valued for their versatility and reliability, they play a key role in keeping many machines running. Like other advanced devices, KEB inverters feature a comprehensive self-diagnostic system that facilitates problem identification by displaying specific error codes. Below is a practical overview of selected common error messages for the popular B6 and F5 series, along with their possible causes.
Error E. EF - External Input
E. EF - Possible cause of the KEB-COMBIVERT inverter error
The inverter reports error E. EF when a trigger signal appears on one of the programmed digital inputs set as an “external error input.” This means that an external system has sent an emergency stop signal or reported a fault directly to the inverter.
If the problem persists, contact a professional service provider: inverter repair.
Error E. Pu - Power Module
E. Pu - Possible cause of the KEB-COMBIVERT inverter error
The E. Pu message indicates a general fault in the inverter’s power module circuit. The most common cause of this error is a failure of the internal cooling system, specifically a damaged or blocked fan, which leads to disruptions in heat dissipation from the power circuits.
If the problem persists, contact a professional service provider: inverter repair.
Error E. br - Brake control
E. br - Possible cause of the KEB-COMBIVERT inverter error
Error E. br occurs when the mechanical brake control function is enabled. It can occur in several scenarios when attempting to release the brake: when a missing motor phase is detected, when the load reaches the system’s hardware current limit, or when the load during startup is below the defined minimum level.
If the problem persists, contact a professional service provider: inverter repair.
Error E.buS - Watchdog
E.buS - possible cause of the KEB-COMBIVERT inverter error
The inverter registers an E.buS error when the set communication check time (the so-called Watchdog) is exceeded. This indicates an interruption or loss of stable communication between the inverter and the master device.
If the problem persists, contact a professional service provider: inverter repair.
Error E.Cdd - Drive data calculation
E.Cdd - possible cause of the KEB-COMBIVERT inverter error
The E.Cdd message is displayed when an error occurs during the inverter’s automatic measurement of the motor stator resistance. This prevents the correct calculation of the parameters necessary for optimal drive control.
If the problem persists, contact a professional service provider: inverter repair.
Error E.dOH - Motor Overheating
E.dOH - Possible cause of the KEB-COMBIVERT inverter error
Error E.dOH indicates that the motor's thermal protection has tripped (e.g., the PTC thermistor connected to terminals T1/T2). The cause may be an actual motor overload, a break in the wire connecting the temperature sensor to the inverter, or resistance at the terminals exceeding the trip threshold (often >1650 Ohms).
If the problem persists, contact a professional service provider: inverter repair.
Error E.dri - Power supply circuit relay
E.dri - possible cause of the KEB-COMBIVERT inverter error
The inverter reports error E.dri when it detects a malfunction in the voltage control relay in the power module. This occurs when the relay fails to engage despite a start enable signal being issued, or when it fails to disengage after the signal ceases.
If the problem persists, contact a professional service provider: inverter repair.
E.EEP error - Faulty EEPROM
E.EEP - possible cause of the KEB-COMBIVERT inverter error
The E.EEP message indicates a fault in the inverter’s internal EEPROM memory, where configuration parameters are stored. The device cannot permanently save new settings. Although operation may be possible after resetting the device, changes to the parameters will not be retained after power is turned off.
If the problem persists, contact a professional service provider: inverter repair.
Error E.iEd - NPN/PNP Switching
E.iEd - Possible cause of the KEB-COMBIVERT inverter error
Error E.iEd occurs due to physical damage to the digital input or a hardware error during the process of switching the control input logic between NPN and PNP standards.
If the problem persists, contact a professional service provider: inverter repair.
Error E.InI - MFC failed to boot
E.InI - Possible cause of the KEB-COMBIVERT inverter error
The inverter displays the E.InI error in the event of problems with the initialization and startup of the MFC (Multi-Function Control) card, which prevents the entire device from operating properly.
If the problem persists, contact a professional service provider: inverter repair.
Error E.LSF - Charging circuit
E.LSF - possible cause of the KEB-COMBIVERT inverter error
Error E.LSF indicates that the charging circuit relay did not operate correctly during the device’s startup phase. This may be caused by insufficient or incorrect input voltage, high losses in the power supply circuit, a damaged braking resistor, or a malfunction of the charging circuit shunt itself.
If the problem persists, contact a professional service provider: inverter repair.
Error E. OC - Overcurrent
E. OC - Possible cause of the KEB-COMBIVERT inverter error
The E. OC message appears immediately when the inverter's defined permissible peak current is exceeded. This may be caused by an output short circuit, a ground fault in the motor circuit, an excessively long motor cable, or acceleration/deceleration ramp settings that are too aggressive relative to the mechanical load.
If the problem persists, contact a professional service provider: inverter repair.
Error E. OH - Excessive cooling element temperature
E. OH - possible cause of the KEB-COMBIVERT inverter error
The inverter registers E. OH when the temperature of the power circuit heat sink exceeds the safe threshold. The most common causes are a dirty or blocked fan, excessively high ambient temperature in the control cabinet, or installation of the device without observing the required ventilation clearances.
If the problem persists, contact a professional service provider: inverter repair.
Error E.OH2 - Motor protection function
E.OH2 - Possible cause of the KEB-COMBIVERT inverter error
Error E.OH2 indicates that the programmed motor overload protection function has been triggered. Based on an algorithm, the inverter determined that the motor was operating under conditions that could lead to overheating and cut off the power supply to protect it.
If the problem persists, contact a professional service provider: inverter repair.
Error E.OHI - Excessive internal temperature
E.OHI - Possible cause of the KEB-COMBIVERT inverter error
The E.OHI message appears when the sensors detect an excessively high temperature inside the inverter housing (in the area of the electronic control circuits), regardless of the temperature of the power module heat sink itself.
If the problem persists, contact a professional service provider: inverter repair.
Error E. OL - Overload
E. OL - possible cause of a KEB-COMBIVERT inverter error
Error E. OL (Ixt overload) indicates that the inverter operated at a current exceeding the rated current for a longer period than its overload characteristics allow. Possible causes include mechanical faults, poor controller compensation, incorrect motor wiring, or simply an inverter that is undersized for the application.
If the problem persists, contact a professional service provider: inverter repair.
Error E.OL2 - Overload in the standstill phase
E.OL2 - possible cause of the KEB-COMBIVERT inverter error
The inverter reports E.OL2 when the permissible continuous current is exceeded while the motor shaft is at rest. As with E.OL, this usually indicates mechanical resistance or incorrect power selection for the device.
If the problem persists, contact a professional service provider: inverter repair.
Error E. OP - Overvoltage
E. OP - Possible cause of the KEB-COMBIVERT inverter error
Error E. OP indicates that the voltage in the inverter’s intermediate circuit has risen dangerously above the permissible limit. This most often occurs during sudden braking of heavy loads, in the absence of or damage to the braking resistor, or due to excessively high voltage in the power supply network.
If the problem persists, contact a professional service provider: inverter repair.
Error E.OS - Overspeed
E.OS - Possible cause of the KEB-COMBIVERT inverter error
The inverter displays error E.OS when a signal is received from the measurement system indicating that the actual rotational speed of the motor shaft has exceeded the maximum safe output speed defined in the parameters.
If the problem persists, contact a professional service provider: inverter repair.
Error E.Puch - Power module changed
E.Puch - possible cause of KEB-COMBIVERT inverter error
The E.Puch error occurs when the control card detects a change in the power module identifier. This usually requires a software procedure to initialize parameters dependent on the new power module.
If the problem persists, contact a professional service provider: inverter repair.
E.Puci error - Power supply not recognized
E.Puci - Possible cause of the KEB-COMBIVERT inverter error
The E.Puci message is an initialization error. The control card is unable to correctly recognize the connected power module, or the module is reporting an identifier that is considered invalid in this configuration.
If the problem persists, contact a professional service provider: inverter repair.
Error E.PUCO - Communication with the power module
E.PUCO - Possible cause of the KEB-COMBIVERT inverter error
The inverter reports error E.PUCO when an internal communication failure occurs and the control card does not receive an acknowledgment while attempting to write a parameter value directly to the power module.
If the problem persists, contact a professional service provider: inverter repair.
Error E.SbuS - Bus synchronization
E.SbuS - Possible cause of the KEB-COMBIVERT inverter error
The E.SbuS error indicates a problem on the system bus, preventing proper synchronization of data exchange between devices in the communication network.
If the problem persists, contact a professional service provider: inverter repair.
Error E.SEt - Parameter set selection
E.SEt - Possible cause of the KEB-COMBIVERT inverter error
The E.SEt message appears when the system attempts to read or write data to a parameter set that has been locked or is unavailable in the current configuration.
If the problem persists, contact a professional service provider: inverter repair.
Error E. UP - Undervoltage
E. UP - Possible cause of the KEB-COMBIVERT inverter error
The inverter registers error E. UP when the voltage in the intermediate circuit drops below the permissible minimum value. The cause may be too low or unstable supply voltage from the power grid, a faulty mains contactor/fuse, large voltage drops resulting from poor wiring, or a loss of power supply during rapid acceleration of the machine.
If the problem persists, contact a professional service provider: inverter repair.
Error E.UPh - Current Phase
E.UPh - possible cause of the KEB-COMBIVERT inverter error
The E.UPh message indicates that the detection system has detected the absence of one of the phases in the supply voltage from the mains.
If the problem persists, contact a professional service provider: inverter repair.
PUIn / E.PUIN Error - Power Module Firmware
PUIn / E.PUIN - Possible Cause of KEB-COMBIVERT Inverter Error
The PUIn error indicates a system hardware incompatibility. The software versions installed on the control card and in its dedicated power module are not compatible with each other and prevent the two components from working together properly.
If the problem persists, contact a professional service provider: inverter repair.
