The original main transformer, traction motors and pneumatic switches of the travel direction and driving-brake mode remained in place. Traction converters, the traction drive controller and auxiliary drive converters were completely replaced.

Basic characteristics of POLL’s participation in the project:

• Traction converter circuit diagram design
• Design and manufacture of traction converter controllers
• Complete development of programme equipment
• Design and manufacture of AC/DC 230V AC/560V DC converter for powering inverters of auxiliary drives

Each traction converter is used to power one traction motor. Each motor drives one chassis of an electric car. There are a total of four traction converters on one vehicle, usually consisting of two electric cars and four rail cars. The traction converters are based on IGCT thyristors produced by ABB (formerly Semiconductors). In driving mode, the traction motor is powered by a maximum voltage of 800V and a maximum current of 1100A. The input H-bridge of the traction converter optimises the shape of the current drawn from the overhead line. In braking mode, EDB braking to almost a complete stop is ensured thanks to the connection of traction converters. The motors are de-energised continuously in driving and braking modes.

Each traction converter is controlled by its own controller. Two controllers are placed in one common chassis, but they are functionally independent. The controllers regulate the currents and voltages of the traction converters according to the driver’s instructions, control the pneumatic switches of driving – brake mode, control the intensity of traction converter cooling, and prevent wheels from slipping and skidding. Software algorithms are optimised to ensure minimal ripple current from the overhead line and to eliminate interfering reverse currents at the frequencies used by the track circuits of the train protection system. 

The first electric car 560 007-7 was refurbished in Pars Šumperk. The revitalisation and testing took place in DKV Brno.  In 2004, design tests were conducted in ŽZO Cerhenice.  By 2010, six multiple units (12 electric rail cars) of the 560 series were refurbished this way.