UPS systems

UPS systems not only protect against power failures but also against other mains interruptions such as voltage interruptions and frequency fluctuations. In this way, connected systems receive a high-grade current, which clearly increases the service life of the power supply packs.

UPS systems are divided into three classes:

  • VFD (offline UPS) - Voltage + Frequency Dependent
  • VI (line interactive UPS) - Voltage Independent
  • VFI (online UPS) - Voltage + Frequency Independent


    • Because VFD systems cost only slightly less than VI systems, these units are not really deployed in professional operation.
    VI systems (line interactive)
    VI systems (line interactive) Protection against:
    • Network failure
    • Power drops
    • Voltage peaks
    • Voltage surges

    Inexpensive UPS systems for protection against most network failures
    VFI systems (online)
    VFI systems (online) Added protection against:
    • Voltage failure
    • voltage distortion
    • voltage oscillation
    • frequency fluctuation

    VFI (online) UPS systems deliver extensive protection against power failure except in the event of lightning.