Siemens micromaster 420 frequency inverters siemens 6se6420 2ad22 2ba1 this universal frequency inverter is from the micromaster 420 series and are designed for use with 3 phase networks the unit has a modular design and the extensive standard functions can be supplemented with a variety of options quickly and simply the inverter is easy to set up and use and the compact design and screwless control terminals means that it is easy to integrate wherever required typically used in conveyor