Industrial Applications


FRIEM designs, manufactures and delivers Worldwide all types of Diode, Thyristor and IGBT Power Converters for:
– Electrochemistry
– Metal Refining
– DC Arc Furnaces
– Plasma Torch
– Graphite Refining
– Heating

Thanks to the experience matured in more than fifty years of activity FRIEM is now capable to supply air, water and deionized water cooled Rectifiers and Converters giving to the customer a complete Conversion System tailored on his application and complying with IEC or ANSI/IEEE Standards.

This ability also allows FRIEM to design and supply Interphase Reactors, Smoothing Reactors, Power Factor Correction and Harmonic Filter systems and to support the rectifier transformer manufacturer in designing reliable and efficient machinery. FRIEM can also provide Worldwide erection and commissioning services together with a reliable full after-sale assistance and supplying of spare parts.

FRIEM’s Rectifiers advantages

The special design of the Power Section (semiconductors’ heatsink and current conductors), proprietary of FRIEM, grants:

  • High Efficiency thanks to the reduced losses
  • Short circuit high withstand capacity through to the robust structure
  • Production continuity and long operation life achieved with the low operating temperature of the power components
  • Reliability thanks to many years of experience
  • Simplified design of the Transformer’s secondary terminals

The dedicated Digital Regulator, FRIEM DRP type, based on the last generation digital technology, provides:

  • High accuracy and regulating performances
  • Easy, fast setting and adjustment of the main parameters
  • Reading and recording of all the main measures
  • Oscillographic Recording of current and voltage waveforms

Technical Characteristics

Operating Characteristics
  • Connection: Bridge - Double Bridge (Series or Parallel) - Double Star - 2x Double Star - Step-down Chopper
  • Type: Thyristor, Diode, IGBT
  • Cooling: Air, Water, Deionized Water
  • AC Input Voltage: From 350V-3 Ph. up to 220kV-3 Ph., 50 or 60Hz.
  • DC Output Voltage: Up to 1500V
  • DC Output Current: Up to 150kA in only one rectifier cubicle; up to 450kA with more units in parallel
  • DC Output Power: Up to more than 60MW with only one rectifier cubicle
  • Control: Current, Voltage and Power regulation thyristor phase firing control on load tap changer and saturable reactors for diode rectifier
  • IGBT switching control
  • Pulses: 6, 12, 18, 24 or more
  • Standards: IEC 60146 - ANSI/IEE
Designing and Manufacturing Characteristics
  • Exclusive aluminium extruded bars
  • High efficiency and reduced losses
  • High Dynamic Stress Withstand
  • Low operating temperatures
  • Non-Magnetic Material Rectifier Cubicle
  • Up to NEMA4x Protection degree (standard IP41)
  • High Accuracy metering Systems
  • Interphase Reactor for 12 Pulses Double Bridges in Parallel
  • High Current Smoothing Reactors for special application (DC-Arc Furnaces)
  • Control combining PLC, digital regulator and electronic boards
  • Transformer operation control and signals acquisition
  • Local and/or remote control
  • Serial Communication for interface with DCS (Modbus, Profibus DP, Ethernet, FMS or Datahighway Plus protocols)
  • Alarm and trip messages history
Regulation, Protection and Measurement Features
  • Dedicated Digital Regulator, FRIEM DRP Type, allowing high accuracy (15 kHz sampling frequency)
  • Electrical parameters easy and fast setting through local membrane keyboard or PC
  • Main parameters and events (Trip and Alarms) recording, including Oscillographic recording (voltage and current waveforms)
  • O/C, O/V, U/V, Phase Sequence Protection
  • Semiconductor Protection and Alarm devices (n-1) or (n-2) Semiconductor Redundancy
  • Supervision and Control of Current sharing between electrolysis cell lines in parallel (Chloralkali)
  • Automatic Protection against Output Circuit Opening (Metal Refining)
  • Control of the by-pass of electrolysis cell for process maintenance purpose (Chloralkali and Metal Refining)
  • DC Earth Fault Protection
  • Full Temperature Monitoring and Thermal Protection
  • Cooling Circuit Monitoring (Pressure, Flow, Conductivity)
  • Cooling System Redundancy