With more than 60 years experience FRIEM is World Leader in the design and manufacturing of Special Rectifiers and Power Converters. Reliability, availability and efficiency are granted by our dedicated solutions for the power section and for the control. Moreover we can test the Rectifiers up to more than 50kA and the Power Converters up to 1 MVA in our Test Rooms. FRIEM is capable of supplying air, water and deionizedwater cooled Rectifiers and Converters giving the
customera complete Conversion System tailored on his application and complying with IEC or ANSI/ IEEE Standards.

Advantages and Protection Features 
Reliability and Availability

• N+1 Semiconductors redundancy: standard
• Cooling System redundancy: standard
• Control System self-diagnostic: standard
Efficiency Short Delivery and Start-Up Time
• Proprietary Internal Busbar design with  reduced losses
• Simplified design of Transformer-Rectifier  Connection
• Optimised design for phases and thyristors  balancing 

Short Delivery and Start-Up Time
• Reduced delivery time thanks to Modular design
• Reduced installation and commissioning time
• Fast Start-up and operation turning with the 
 dedicated Digital Regulator

• Latest IEC and ANSI/IEEE Standards
• FRIEM design protection devices
Protection Features
• O/C, O/V, U/V, Phase Sequence Protection
• Overcurrent and Short circuit protection  at the Rectifier Input
• Semiconductor Protection and Alarm devices
• (N+1) or (N+2) Semiconductor redundancy
• Automatic Protection against Output Circuit  Opening
• Supervision and control of current sharing  between Electrolysis Cell Lines in parallel
• DC Earth Fault protection
• Arc Flash Protection
• Free Wheeling System
• Full Temperature monitoring and Thermal  protection
• Thyristors/Fuses temperature monitor
• Cooling Circuit monitoring (Pressure, Flow Rate,  Conductivity)

Design and Manufacturing
Power Section

• Exclusive Aluminium extruded Busbars
• High efficiency and high dynamic stress withstand
• High reliability and long life operation due to  reduced operating temperatures
• Optimised Nr. of Semiconductors and N+1  Valves redundancy as standard
• Non-Magnetic material Rectifier Cubicle
• Simplified design of Transformer’s Phases  Connections
• Optimised Design for Thyristors balancing
• Easy maintenance
Cooling Section
• Deionised to raw water Cooling System (dWFWF)
• Deionised water to forced air Cooling System  (dWFAF)
• Monitoring of temperature, under pressure,  min flow, min and max level, high conductivity  of deionised water
• 50% or 100% redundancy
• Open or enclosed section
• Easy maintenance

Control Section
• Digital regulation (FRIEM DRP) for Diodes,  Thyristor and IGBT
• Original FRIEM electronic boards
• Thyristors electronic balance
• PLC and OP control and automation (different  brands available)
• Hot and warm PLC redundancy
• Fiber Optics Thyristors and Control connection
• Redundant DC Current measure
• All PLC brands available
• Local, Remote and Master control
• Remote control via Modem/Internet DRP Digital Regulation
• 15kHz Sampling Frequency
• High accuracy regulation of current, voltage  and power
• Reading and recording of all main   measurements and events
• Current and Voltage Oscillographic recording  and Load Profile
• Easy and fast setting of the Regulation  and Protection Parameters
• Reduced commissioning and start-up time