cmindustrysupply cmindustrysupply

Leading Industrial Automation Solution Provider

Servo Drive & Motor Expert | VFD AC Drive Repair

Posted on 9th Aug 2023

Comparison of KEB G6 VFD and Lenze i550 VFD


According to CM Industry Supply Automation, the automation industry offers a wide range of possibilities when looking for an open-loop VFD for your application. The KEB Combivert G6 and the Lenze i550 are thoroughly compared in this blog post. Find out how the two devices compare and contrast in terms of communication capabilities, input and output power options, functional safety, and more.

Application Targets

Both the G6 and the i550 are open-loop VFDs, allowing them to operate three-phase induction motors without the need for an encoder or other feedback mechanism. They accomplish this by controlling the motor's velocity using sensorless vector control and V/Hz. For high-efficiency fan and pump applications, the G6 additionally supports SCL (synchronous-sensorless control), which operates AC PM (permanent magnet) servo motors without providing feedback.

Food manufacturing, packaging, conveyor and storage technologies, pumps, and compressors are examples of common open-loop uses.

Choices for Communication

The kind of fieldbus protocol you use to interact with the PLC or HMI is another important factor.   

EtherCAT, VARAN, IO Link, and CANopen are some of the available G6 VFD connection possibilities. KEB supports this protocol in our S6 VFD series, despite the fact that it is incompatible with EtherNET/IP.

A wide range of communication options are covered by the Lenze Drive i550 VFD. It uses the CANopen, EtherCAT, EtherNET/IP, IO-Link, Modbus RTU, Modbus TCP, Powerlink, Profibus, and Profinet fieldbus protocols for communication.

Options for Input and Output Power

When selecting an open-loop VFD for your application, the input power is crucial.  To avoid problems during the first installation, make sure the end user's facility has the appropriate power source available to run the VFD.

Both 230V single-phase and 400/480V three-phase power are available for the KEB G6 drive's input power. The G6 runs motors up to 2 HP in the 230V single-phase class. The G6 can, however, operate 40 HP motors with a 400/480V three-phase power source. Any open-loop applications requiring motors greater than 40 HP and up to 600 HP must be run with a drive from the KEB Drive F6 series.

The input power options are more varied on the Lenze i550. It differs from the G6 in that it can control motors with a power range of 1/3 HP to 1 1/2 HP using 120V, single-phase power.  The i550 accepts a 230V power source in one or three phases when it offers 230V power. It can run motors using 230V single-phase power from 1/3rd HP to 3 HP and 230V three-phase power from 1/3rd HP to 7.5 HP. The Lenze i550 can control motors with a power range of 1/2 HP to 150 HP using a power supply of 400/480V three-phase power.

Available I/O

A wide range of I/O options are available on both the G6 and the i550. The number of programmable analogue inputs and outputs, digital inputs and outputs, and relays on each drive are displayed in the table below.

The G6's extra digital inputs and relay are a benefit. For instance, the additional digital inputs may cause a jog function or error reset, or the two relays could be configured to control a brake and alert the VFD to a malfunction.

Effective Safety  

Functional safety is necessary in some situations. It's critical that the VFD you select for your application adheres to the necessary safety regulations.   

According to category 3, EN ISO 13849-1 PL e/ IEC EN 62061, SIL 3, Safe Torque Off (STO), an integrated 2-channel safety function, is a standard feature of KEB's G6 VFDs. These inputs are made to allow the connection of safety switchgear units with test pulses (OSSD signals). The first channel turns off the control CPU's pulse pattern, while the second channel turns off the power to the driver's IGBTs' gate control supply.


In almost all open-loop applications, the Lenze i550 can be replaced by KEB's G6 VFD.  To talk about your application and a KEB solution, get in touch with a KEB engineer now.