1 Early uninterruptible power system is divided into on-line (ON-LINE) and offline (OFF-LINE) two categories, manufacturers have recently launched an online interactive (LINE INTERACTIVE), its characteristics between on-line and off-line between, but in its operating characteristics and power supply, it should be classified as off-line.
  (2) according to the input / output phase and single-phase input voltage can be divided into single-phase output (used 10KVA less off-line, line-interactive, on-line and other small capacity), three-phase input and single phase output (used 10KVA These on-line), three-phase input three phase output (used in more than 20KVA line capacity).