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Thyristor power modules

The Thyro-C thyristor power modules for PQ low-voltage power capacitors is the plug-and-go solution for dynamic reactive power compensation systems.
Due to its characteristics, using a Thyro-C instead of conventional control elements, such as capacitor air contactors, results in the following advantages:

  • Long service life due to virtually unlimited switching frequency
  • Soft switching of the capacitors during the current zero point
  • Short switching time delay
  • Suitable for installation in dynamic realtime compensation systems
  • DC or AC voltage control
  • Complete and compact module consisting of two switching units with cooling element, power section and control electronics
  • No additional supply voltage required
  • No noise emissions
  • Simple to install

Fields of application

The Thyro-C thyristor power modules can be used in combination with:

  • Programmable logic controllers PLC
  • Reactive power controllers or process controllers
  • Computer systems or process control technologies

in particular for:

  • rapid and
  • Wear-free switching

Typical fields of application are e. g.:

  • crane systems
  • lift systems
  • spot welding machines

Mode of operation

The Thyro-C is suitable for switching capacitive loads, i.e. capacitors with or without reactor protection. Due to the high reverse charging currents, parallel operation of Thyro-C modules in combination with capacitor contactors in one low-voltage distribution is only allowed with reactor-protected units.
Please ask our advice if there are already compensation devices installed in the supply network.

Functional principle

The adjuster consist of two thyristor modules, which switch the phases L1 and L3. Phase L2 is not switched. Alternatively the thyristor module can be used for single-phase operation.

Control input

The Thyro-C has control inputs that are galvanically isolated from the network (terminal X1).
The control signal “ON” is indicated by “ON” on LED display on the front plate.

Discharge of the capacitors

Power capacitors must be equipped with non-switched discharge devices in compliance with EN 60831.  As standard practice only resistors for the discharge of the capacitors may be used, because the capacitors are continuously recharged at peak supply voltage while switched off.
Important: Even when the thyristor modules are not carrying current, the capacitors are still charged with voltage!  Discharge of the capacitors is not effected until the circuit stage is completely disconnected from the supply network, i.e., for example that the disconnectors are open.