Reliable power for a sustainable world

  Riello Connect   


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Power Range: 100 - 800 kVA


  • 95.5% operating efficiency (Online mode) reduces energy waste 
  • Ideal for systems powered by generators or MV/LV transformers 
  • Parallel up to 8 (distributed) or up to 7 (centralised) for extra capacity or redundancy 
  • Efficiency Control System optimises efficiency in parallel installations 
  • Galvanic isolation  


Master HE (MHE) is a UPS that combines maximum protection with exceptional efficiency in mission-critical applications such as data centres, electro-medical devices, telecoms networks and security systems. Can operate with or without a neutral connection. 

Delivers high-quality unity power (kW = kVA) and incorporates an output isolation transformer to ensure galvanic isolation. Hot System Expansion means you can add units for extra capacity or redundancy without requiring the UPS to transfer to bypass. 

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Delivering outstanding performance at lower operating costs, the Master HE range of super-efficient UPS systems is the perfect option for protecting mission-critical and industrial loads. 

With a power range of 100-800 kVA, up to 8 units can be installed in parallel to increase capacity or redundancy depending on the requirements. 

Using advanced online double conversion technologies, the Master HE is designed to protect data centres, IT and telecommunications networks, electro-medical devices, security systems, and industrial loads from blackouts and other damaging power disturbances. 

Its IGBT-based rectifier produces far greater operational efficiency compared against the more conventional thyristor-based systems. In online mode, operational efficiency of 95.5% stands comparison with transformerless UPS power supplies. 

Providing a unity power factor, it includes an output isolation transformer which offers better load protection, enables the UPS to be supplied from two independent lines, and guarantees higher immunity to any harmonics generated by the load. 

Users can manually select or programme a variety of operating modes that improve system performance or efficiency: 

  • Online Mode: maximum load protection and output voltage quality 
  • Eco Mode: maximum efficiency up to 99% as the load is powered by the mains only 
  • Smart Active Mode: UPS automatically decides what mode to run depending on the stability of the incoming supply 
  • Standby Off Mode: for loads such as emergency lighting, which don’t need power until the mains supply fails 
  • Frequency Converter Mode: enables the output frequency to be different to the UPS input frequency 

Delivering high power in a compact footprint, for example, a 250 kVA model can be installed in 0.85m2 space, the Master HE can be configured in a variety of ways, such as: 

  • UPS Group Synchroniser (UGS): enables 2 or more non-parallel UPS devices to remain synchronised even during mains power failure. UGS also enables a Riello UPS to synchronise with another independent power source, even one with a different power rating. 
  • Parallel Systems Joiner (PSJ): this connects 2 groups of UPS in parallel using a power coupling switch. If one of the UPS in the group fails, it is automatically excluded and the PSJ links the remaining UPS to the other group through an external bypass. 

Quick maintenance and service access is available thanks to a removable front panel, which also incorporates an advanced LCD display panel showcasing UPS status and alarms, input and output voltage, battery levels, and other measurements that can be used to monitor performance and calculate data centre power usage effectiveness (PUE). 

Integrates with Riello UPS’s full suite of monitoring and networking communications software such as PowerNetGuard and PowerShield3.

  • Operational efficiency up to 95.5%
  • Up to 8 Master HE can be installed in parallel for extra capacity or redundancy
  • Delivers quality power in mission-critical environments like data centres, telecoms networks, security systems, electro-medical devices, and industrial applications

Brochures and data sheets

Master HE

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Technical specifications of the model