Online UPS

NST-GS Series (20-300 KVA)

NST-GS Series (20-300 KVA)
There Phase In/Three Phase Out
On-Line Double Conversion

QUALITY POWER SUPPLY EPI NST-GS is an On-Line double conversion (VFI) UPS with filtered and stabilized sinusoidal output voltage. NST-GS series is immune to the interferences on the electric power supply line as it has special input and output filters.

The digital control of the appliance considerably improves reliability, since a reduction in electronic components lowers the likelihood of breakdowns. Digital control is provided by the microprocessor that, in the NST-GS series, controls all the internal parameters, thus increasing reliability and performance. In parallel connections, digital control ensures balance of the currents, which generally change over time due to phenomena such as vibrations and temperature, between the UPS units and the exchange of information with no need for manual tuning. NST-GS has been designed so that it can be connected in parallel even after the installation of the first unit. The power availability can be increased thanks to various configurations available such as the parallel configuration, the Dual Bus function and the Dynamic Dual Bus system. Online double conversion mode with an output power factor of 1.0 providing 15% more active power compares to UPS with a power factor of 0.8.

Optimal battery management includes:

  • Periodic battery test,
  • Protection against deep discharge,
  • Recharge temperature compensated.

If required, the unit can work in ECO mode to increase efficiency up to 98% and consequently reduce energy dissipation and costs. In this operating mode the mains is the priority source and the load is switched over to the Inverter only when the mains characteristics exceed the preset limits.


  • In-Built Galvanic Isolation Transformer
  • High-efficient DSP chip
  • Outstanding electric property
  • Good looking and excellent hardware
  • N+X parallel redundancy (compatible to battery share in the parallel mode)
  • Frontal-board operation and maintenance
  • Twin-channel line input
  • Remote monitoring
  • Intelligent management of battery charging and discharging
  • Flexible battery arrangement

The UPS can contains the following hardware interfaces:

  • RS232 serial port,
  • SNMP
  • RJ45,
  • GPRS
  • Dry contacts,
  • EPO (Emergency Power Off)

NST-GS Series (20-300 KVA)
There Phase In/Three Phase Out
On-Line Double Conversion