Line-interactive UPS (VI) UPS topologies

“Voltage independent” UPS in compliance with IEC 62040-3, also known as line interactive, protects against the most common power problems experienced in a network. Here the UPS also monitors the voltage level and balances under and over voltages. The VI technology offers a good compromise between reasonable security and moderate operating costs.
UPS topologies - line-interactive UPS VI


  • Extremely wide input voltage window
  • Rugged design
  • High efficiency
  • Low operating costs



  • Transfer gap (some ms) AVR control rage/inverter transfer
  • load is fed by unfiltered voltage (no correction by the inverter)
Diagram of a line-interactive UPS
Diagram of a line-interactive UPS


  • Protect Alpha Line-inactive UPS

    VI (Line-interactive)

    450 VA
    600 VA
    800 VA
    1200 VA
  • Protect B.PRO line-interactive UPS, Tower-Rack

    line-interactive (VI)
    750 VA1800 VA
    1000 VA2300 VA
    1400 VA3000 VA
  • Protect A line-interactive UPS

    VI (Line-interactive)

    500 VA
    750 VA
    1000 VA
    1400 VA