Static Frequency Converter ELSTR 75

Static Frequency Converter ELSTR 75

This device is used as a substitution for rotary converters 50 / 75 Hz that are supplying security and protection railway circuits at 75 Hz. It is producing sinusoidal voltage 3 x 380 V / 75 Hz from 3 x 400 V / 50 Hz through static frequency converter.

In comparison with systems that are based on rotary converters, can be several advantages clearly seen:

  • Higher efficiency
  • Lower running costs
  • Lower noise level
  • Dimensions
  • Easy installation
  • Synchronization of two remote converters

For synchronization is device equipped with synchronization module.

The power is 90 kVA (ver. ELSTR 90/75) or by request can be source with higher power used.


Working Principle

Static converter is supplied from 3 x 400 V / 50 Hz - this voltage is rectified, smoothed with capacitor battery and then inverted through Transistor Bridge to 75 Hz. Sinusoidal filter is implemented for the smoothing of output voltage 3 x 380 V. Post-transformation is done at HV level of a substation that does not belong to ELSTR.


Security control, i.e. control of rated voltage and frequency output provides circuit converter control (CCC). For its operation needs ELSTR auxiliary voltage DC 24 V.

ELSTR is controlled by TERM401 panel that is located on the front door of a switchboard. This panel allows complete parameters adjustment. After that is remote control possible - switch on/off, find out in which mode does it work.

Modification of power, voltage and other parameters is possible by request.